WorldWideScience

Sample records for alternating current motors

  1. Speed controller for an alternating - current motor

    International Nuclear Information System (INIS)

    A controller for a multi-phase ac motor that is subject to a large inertial load, e.g. an induction motor driving a heavy spinning rotor of a neutron chopper that must be rotated in phase-locked synchronism with a reference pulse train that is representative of an ac power supply signal Esub(L) having a meandering line frequency, includes a sensor which provides a feedback pulse train representative of the actual speed of the motor which is compared (by counting clock pulses between feedback pulses) with a reference clock signal in a computing unit to provide a motor control signal Esub(c). The motor control signal is a weighted linear sum of a speed error signal, a phase error signal, and a drift error signal, the magnitudes of which are recalculated and updated with each revolution of the motor shaft. The speed error signal is constant for large speed errors but highly sensitive to small speed errors. The stator windings of the motor are driven by variable-frequency power amplifiers which are controlled by the motor control signal Esub(c) via PROMs which store digital representations of sine and cosine waveforms in quadrature. (author)

  2. Alternating-Current Motor Drive for Electric Vehicles

    Science.gov (United States)

    Krauthamer, S.; Rippel, W. E.

    1982-01-01

    New electric drive controls speed of a polyphase as motor by varying frequency of inverter output. Closed-loop current-sensing circuit automatically adjusts frequency of voltage-controlled oscillator that controls inverter frequency, to limit starting and accelerating surges. Efficient inverter and ac motor would give electric vehicles extra miles per battery charge.

  3. A new system of alternating current motors and transformers and other essays

    CERN Document Server

    Tesla, Nikola

    2013-01-01

    Nikola Tesla was a genius who revolutionized how the world looks at electricity. During college his professors explained that it was impossible to design an engine without commutators or brushes. Tesla was unconvinced that such was necessary or even particularly desirable. It was then that Tesla began his work on the rotating field motor that ultimately gave birth to the modern age. In May of 1888, Tesla delivered his lecture ""A New System of Alternating Current Motors and Transformers"" before The American Institute of Electrical Engineers and the world has never been the same.

  4. Phase and Frequency-Dependent Effects of Transcranial Alternating Current Stimulation on Motor Cortical Excitability.

    Science.gov (United States)

    Nakazono, Hisato; Ogata, Katsuya; Kuroda, Tsuyoshi; Tobimatsu, Shozo

    2016-01-01

    Transcranial alternating current stimulation (tACS) can entrain ongoing brain oscillations and modulate the motor system in a frequency-dependent manner. Recent animal studies have demonstrated that the phase of a sinusoidal current also has an important role in modulation of neuronal activity. However, the phase effects of tACS on the human motor system are largely unknown. Here, we systematically investigated the effects of tACS phase and frequency on the primary motor cortex (M1) by using motor evoked potentials (MEPs) with transcranial magnetic stimulation (TMS). First, we compared the phase effects (90°, 180°, 270° or 360°) of 10 and 20 Hz tACS on MEPs. The 20 Hz tACS significantly increased M1 excitability compared with the 10 Hz tACS at 90° phase only. Second, we studied the 90° phase effect on MEPs at different tACS frequencies (5, 10, 20 or 40 Hz). The 20 vs. 10 Hz difference was again observed, but the 90° phase in 5 and 40 Hz tACS did not influence M1 excitability. Third, the 90° phase effects of 10 and 20 Hz tACS were compared with sham stimulation. The 90° phase of 20 Hz tACS enhanced MEP amplitudes compared with sham stimulation, but there was no significant effect of 10 Hz tACS. Taken together, we assume that the differential 90° phase effects on 20 Hz and 10 Hz tACS can be attributed to the neural synchronization modulated by tACS. Our results further underline that phase and frequency are the important factors in the effects of tACS on M1 excitability. PMID:27607431

  5. Research on the variable speed system of large power alternating current motor%Research on the variable speed system of large power alternating current motor

    Institute of Scientific and Technical Information of China (English)

    Li Chongjian

    2012-01-01

    The development status of the variable speed system of large power AC (alternating current) motor drive in China is introduced. The large power AC drive fed by AC-AC converters (cycloconverters) has developed greatly, and some innovations on the theory and engineering technique have been realized. They have been applied to rolling mills, mine hoists, and so on, and remarkable economic and social benefit has been achieved. The development of AC drive fed by large power IGCT (integrated gate commutated thyristors) AC-DC-AC converter is also introduced. It has excellent performance and reliable operation, and has been used in traction.

  6. Digital driver of alternate current motors of the control rods in a nuclear research reactor

    International Nuclear Information System (INIS)

    The updating of the instruments as the operation console of the TRIGA Mark III Salazar Reactor is based on the use of a personal computer that works as data acquisition and control device. The power changes on the reactor have been made through the inserting or extraction of four control rods, that they are operated by mechanisms based in alternate current motors. That is with the object to handling each of the bars and so avoiding too the degradation about the performance of the computer of process. Also it is using four drives of smart kind which do the basic duties for generating the control signals and verifying the sensors state of the limits in continuous form. The computer and drivers are organized as a ring net using the serial port R S-232. The computer of process sends the orders and the identification of destination instrument throughout the net. (Author)

  7. Feedback-Controlled Transcranial Alternating Current Stimulation Reveals a Functional Role of Sleep Spindles in Motor Memory Consolidation.

    Science.gov (United States)

    Lustenberger, Caroline; Boyle, Michael R; Alagapan, Sankaraleengam; Mellin, Juliann M; Vaughn, Bradley V; Fröhlich, Flavio

    2016-08-22

    Transient episodes of brain oscillations are a common feature of both the waking and the sleeping brain. Sleep spindles represent a prominent example of a poorly understood transient brain oscillation that is impaired in disorders such as Alzheimer's disease and schizophrenia. However, the causal role of these bouts of thalamo-cortical oscillations remains unknown. Demonstrating a functional role of sleep spindles in cognitive processes has, so far, been hindered by the lack of a tool to target transient brain oscillations in real time. Here, we show, for the first time, selective enhancement of sleep spindles with non-invasive brain stimulation in humans. We developed a system that detects sleep spindles in real time and applies oscillatory stimulation. Our stimulation selectively enhanced spindle activity as determined by increased sigma activity after transcranial alternating current stimulation (tACS) application. This targeted modulation caused significant enhancement of motor memory consolidation that correlated with the stimulation-induced change in fast spindle activity. Strikingly, we found a similar correlation between motor memory and spindle characteristics during the sham night for the same spindle frequencies and electrode locations. Therefore, our results directly demonstrate a functional relationship between oscillatory spindle activity and cognition. PMID:27476602

  8. Beta band transcranial alternating (tACS and direct current stimulation (tDCS applied after initial learning facilitate retrieval of a motor sequence

    Directory of Open Access Journals (Sweden)

    Vanessa eKrause

    2016-01-01

    Full Text Available The primary motor cortex (M1 contributes to the acquisition and early consolidation of a motor sequence. Although the relevance of M1 excitability for motor learning has been supported, the significance of M1 oscillations remains an open issue. This study aims at investigating to what extent retrieval of a newly learned motor sequence can be differentially affected by motor-cortical transcranial alternating (tACS and direct current stimulation (tDCS. Alpha (10 Hz, beta (20 Hz or sham tACS was applied in 36 right-handers. Anodal or cathodal tDCS was applied in 30 right-handers. Participants learned an eight-digit serial reaction time task (SRTT; sequential vs. random with the right hand. Stimulation was applied to the left M1 after SRTT acquisition at rest for ten minutes. Reaction times were analyzed at baseline, end of acquisition, retrieval immediately after stimulation and reacquisition after eight further sequence repetitions.Reaction times during retrieval were significantly faster following 20 Hz tACS as compared to 10 Hz and sham tACS indicating a facilitation of early consolidation. TDCS yielded faster reaction times, too, independent of polarity. No significant differences between 20 Hz tACS and tDCS effects on retrieval were found suggesting that 20 Hz effects might be associated with altered motor-cortical excitability. Based on the behavioural modulation yielded by tACS and tDCS one might speculate that altered motor-cortical beta oscillations support early motor consolidation possibly associated with neuroplastic reorganization.

  9. Fourth annual report to Congress, Federal Alternative Motor Fuels Programs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-07-01

    This annual report to Congress presents the current status of the alternative fuel vehicle programs being conducted across the country in accordance with the Alternative Motor Fuels Act of 1988. These programs, which represent the most comprehensive data collection effort ever undertaken on alternative fuels, are beginning their fifth year. This report summarizes tests and results from the fourth year.

  10. Bi-modes alternation stepping ultrasonic motors

    Institute of Scientific and Technical Information of China (English)

    Jiamei JIN; Chunsheng ZHAO

    2008-01-01

    Based on the principle of alternative operation of two bending vibration modes in an annular stator, this paper presents a standing-wave stepping ultrasonic motor characterized by no accumulative errors driven by an open-loop control circuitry. The driving forces are generated from the motions of projections on the stator in two modes. The positioning of the motor is achieved by the cooperation between the stator projections and rotor teeth, and the number of the rotors determines the stepping angle of the motor. Two-phase sinusoidal signals corresponding to the two modal frequencies drive the motor bi-direction stepping rotation via a switch unit. The prototype runs steadily without miss-step on trial. The single-step angle displacement of the motor is 2.5°.

  11. Control strategy minimizing the converter-alternating current motor losses: application to electric traction; Strategies de commande minimisant les pertes d'un ensemble convertisseur - machine alternative: application a la traction electrique

    Energy Technology Data Exchange (ETDEWEB)

    Bastiani, Ph.

    2001-02-01

    Improving the efficiency of the converter-alternating current motor system is a major task in electric traction. Global energy optimisation implies a specific approach at system scale. To reach this goal, we have chosen an algebraic method using sub-system models. To start with, a synchronous machine Park model is developed to take account magnetic saturation and iron losses. Then, an averaged model of the voltage inverter is used in order to obtain a simplified model of the losses to be implemented in our optimisation method. This is how the global model is built including losses in the synchronous machine along with the losses of the power converter. Experimental results are there to validate our approach. This study proposes a method based on algebraic formulation of the general laws to control torque. Algorithms take into account magnetic circuits saturation and power losses in both the machine and its converter. Here again, experimental results validate the algorithm on several test benches. Achieved efficiency improvement is important compared to existing usual control strategies. The proposed method can be generalised to other machine-converter systems. As a matter of fact we have extended our study to the induction machine. As a complement ti this study we have looked at the effects natural limitations of voltages and currents in the torque-speed plane. Therefore algebraic formulation of the torque-speed plane and optimisation strategies are proposed including those constraints. (author)

  12. Alternation of Agonists and Antagonists During Turtle Hindlimb Motor Rhythms

    OpenAIRE

    Stein, Paul S.G.

    2010-01-01

    In a variety of vertebrates, including turtle, many classical and contemporary studies of spinal cord neuronal networks generating rhythmic motor behaviors emphasize a Reciprocal Model with alternation of agonists and antagonists, alternation of excitatory and inhibitory postsynaptic potentials, and reciprocal inhibition. Some studies of spinal cord neuronal networks, including those in turtle during scratch motor rhythms, describe a Balanced Model with concurrent excitatory and inhibitory po...

  13. Reducing current reversal time in electric motor control

    Energy Technology Data Exchange (ETDEWEB)

    Bredemann, Michael V

    2014-11-04

    The time required to reverse current flow in an electric motor is reduced by exploiting inductive current that persists in the motor when power is temporarily removed. Energy associated with this inductive current is used to initiate reverse current flow in the motor.

  14. Alternating current for the West

    International Nuclear Information System (INIS)

    In the framework of the reactor EPR construction in the Manche, the authors wonder on the pertinence of this energy choice for the economy and the environment of the West France. They show that there is an alternative to this choice. In a first part a state of the situation concerning the electricity supply and demand in the region is detailed. Then from the local potential of renewable electric power production and the electricity conservation, they propose many concrete actions. (A.L.B.)

  15. Sliding Mode Control of Induction Motor Phase Currents

    DEFF Research Database (Denmark)

    Hansen, R.B.; Hattel, T.; Bork, J;

    1995-01-01

    Sliding mode control of induction motor phase currents are investigated through development of two control concepts.......Sliding mode control of induction motor phase currents are investigated through development of two control concepts....

  16. Experimental Study on Current Decay Characteristics of Persistent Current HTS Magnet by Alternating Magnetic Field

    Science.gov (United States)

    Park, Young Gun; Lee, Chang Young; Hwang, Young Jin; Lee, Woo Seung; Lee, Jiho; Jo, Hyun Chul; Chung, Yoon Do; Ko, Tae Kuk

    This paper deals with a current decay characteristics of a high temperature superconducting (HTS) magnet operated in persistent current mode (PCM). In superconducting synchronous machine applications such as linear synchronous motor (LSM), the superconducting coil is designed to operate in the PCM to obtain steady magnetic field with DC transport current. This superconducting magnet operates on a direct current, but it can be exposed to alternating magnetic field due to the armature winding. When the magnet is subjected to an external time-varying magnetic field, it is possible to result in a decay of the current in PCM system due to AC loss. In this research, a PCM system with armature coil which generates time-varying magnetic field was fabricated to verify current decay characteristics by external alternating magnetic field. The current decay rate was measured by using a hall sensor as functions of amplitude and frequency of armature coil.

  17. An Alternative to Maxwell's Displacement Current

    CERN Document Server

    Wolsky, Alan M

    2014-01-01

    Though sufficient for local conservation of charge, we show that Maxwells displacement current is not necessary. An alternative to the Ampere Maxwell equation is exhibited and the alternative s electric and magnetic fields and scalar and vector potentials are expressed in terms of the charge and current densities. The alternative describes a theory in which action is instantaneous and so may provide a good approximation to Maxwells equations where and when the finite speed of light can be neglected. The result is reminiscent of the Darwin approximation which arose from the study classical charged point particles to order (v/c)2 in the Lagrangian. Unlike Darwin, this approach does not depend on the constitution of the electric current. Instead, this approach grows from a straightforward revision of the Ampere Equation which revision enforces the local conservation of charge.

  18. Current Pharmaceutical Treatments and Alternative Therapies of Parkinson's Disease.

    Science.gov (United States)

    Dong, Jie; Cui, Yanhua; Li, Song; Le, Weidong

    2016-01-01

    Over the decades, pharmaceutical treatments, particularly dopaminergic (DAergic) drugs have been considered as the main therapy against motor symptoms of Parkinson's disease (PD). It is proposed that DAergic drugs in combination with other medications, such as monoamine oxidase type B inhibitors, catechol-O-methyl transferase inhibitors, anticholinergics and other newly developed non-DAergic drugs can make a better control of motor symptoms or alleviate levodopa-induced motor complications. Moreover, non-motor symptoms of PD, such as cognitive, neuropsychiatric, sleep, autonomic and sensory disturbances caused by intrinsic PD pathology or drug-induced side effects, are gaining increasing attention and urgently need to be taken care of due to their impact on quality of life. Currently, neuroprotective therapies have been investigated extensively in pre-clinical studies, and some of them have been subjected to clinical trials. Furthermore, non-pharmaceutical treatments, including deep brain stimulation (DBS), gene therapy, cell replacement therapy and some complementary managements, such as Tai chi, Yoga, traditional herbs and molecular targeted therapies have also been considered as effective alternative therapies to classical pharmaceutics. This review will provide us updated information regarding the current drugs and non-drugs therapies for PD. PMID:26585523

  19. Reactor coolant pump testing using motor current signatures analysis

    Energy Technology Data Exchange (ETDEWEB)

    Burstein, N.; Bellamy, J.

    1996-12-01

    This paper describes reactor coolant pump motor testing carried out at Florida Power Corporation`s Crystal River plant using Framatome Technologies` new EMPATH (Electric Motor Performance Analysis and Trending Hardware) system. EMPATH{trademark} uses an improved form of Motor Current Signature Analysis (MCSA), technology, originally developed at Oak Ridge National Laboratories, for detecting deterioration in the rotors of AC induction motors. Motor Current Signature Analysis (MCSA) is a monitoring tool for motor driven equipment that provides a non-intrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment. The base technology was developed at the Oak Ridge National Laboratory as a means for determining the affects of aging and service wear specifically on motor-operated valves used in nuclear power plant safety systems, but it is applicable to a broad range of electric machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. The motor current variations, resulting from changes in load caused by gears, pulleys, friction, bearings, and other conditions that may change over the life of the motor, are carried by the electrical cables powering the motor and are extracted at any convenient location along the motor lead. These variations modulate the 60 Hz carrier frequency and appear as sidebands in the spectral plot.

  20. Starting characteristics of direct current motors powered by solar cells

    Science.gov (United States)

    Singer, S.; Appelbaum, J.

    1989-01-01

    Direct current motors are used in photovoltaic systems. Important characteristics of electric motors are the starting to rated current and torque ratios. These ratios are dictated by the size of the solar cell array and are different for the various dc motor types. Discussed here is the calculation of the starting to rated current ratio and starting to rated torque ratio of the permanent magnet, and series and shunt excited motors when powered by solar cells for two cases: with and without a maximum-power-point-tracker (MPPT) included in the system. Comparing these two cases, one gets a torque magnification of about 3 for the permanent magnet motor and about 7 for other motor types. The calculation of the torques may assist the PV system designer to determine whether or not to include an MPPT in the system.

  1. Condition monitoring of machinery using motor current signature analysis

    International Nuclear Information System (INIS)

    Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process ''downstream'' of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given. 1 ref., 13 figs

  2. Condition monitoring of machinery using motor current signature analysis

    Science.gov (United States)

    Kryter, R. C.; Haynes, H. D.

    Motor current signature analysis (MCSA) is a powerful monitoring tool for motor-driven equipment that provides a nonintrusive means for detecting the presence of mechanical and electrical abnormalities in the motor and the driven equipment, including altered conditions in the process downstream of the motor-driven equipment. It was developed at the Oak Ridge National Laboratory as a means for determining the effects of aging and service wear systems, but it is applicable to a broad range of machinery. MCSA is based on the recognition that an electric motor (ac or dc) driving a mechanical load acts as an efficient and permanently available transducer by sensing mechanical load variations, large and small, long-term and rapid, and converting them into variations in the induced current generated in the motor windings. These motor current variations are carried by the electrical cables processes as desired. Motor current signatures, obtained in both time and over time to provide early indication of degradation. Successful applications of MCSA technology (patent applied for) include not only motor-operated valves but also pumps of various designs, blowers, and air conditioning systems. Examples are presented briefly, and speculation regarding the applicability of MCSA to a broader range of equipment monitoring and production line testing is also given.

  3. Research on the induction motor current signature for centrifugal pump at cavitation condition

    Directory of Open Access Journals (Sweden)

    Yin Luo

    2015-11-01

    Full Text Available Cavitation is a major undesirable phenomenon for centrifugal pump because it can cause hydraulic performance deterioration, pump damage by pitting and material erosion, and structural vibration and noise. Cavitation can appear within the entire range of the operating conditions; therefore, it must be prevented by all means. Sensorless monitoring technology based on motor current signature analysis is non-intrusive and economic for monitoring motor-driven equipment. Thus, this technology is suitable for centrifugal pump systems. The motor current signature for centrifugal pump load at the cavitation condition is the basis of this technology. However, systematic research is lacking on sensorless monitoring technology based on motor current signature. As a result, the tentative exploration for motor current signature at cavitation load was conducted in this study. The results show that the stator current is still a sinusoidal alternating current strictly to the law of sine. Moreover, the root mean square of the current fluctuates because of different flow regimes in the cavitation progress and decreases because vapor density is smaller than water density when cavitation is fully formed. For the stator current spectrum, the noise level, noise distribution, rotation speed, and vane pass frequency components show features in the cavitation process. These indicator indexes change according to the stage of cavitation development. Thus, the motor current signature analysis is found to be a feasible and cost-effective method for the stages of cavitation condition.

  4. Stability of alternating current gliding arcs

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Salewski, Mirko; Leipold, Frank;

    2014-01-01

    A gliding arc is a quenched plasma that can be operated as a non-thermal plasma at atmospheric pressure and that is thus suitable for large-scale plasma surface treatment. For its practical industrial use the discharge should be extended stably in ambient air. A simple analytical calculation based...... on Ohm’s law indicates that the critical length of alternating current (AC) gliding arc discharge columns can be larger than that of a corresponding direct current (DC) gliding arc. This finding is supported by previously published images of AC and DC gliding arcs. Furthermore, the analysis shows...

  5. Current insights in the development of children's motor imagery ability

    NARCIS (Netherlands)

    Spruijt, S.; Kamp, J. van der; Steenbergen, B.

    2015-01-01

    Over the last two decades, the number of studies on motor imagery in children has witnessed a large expansion. Most studies used the hand laterality judgment paradigm or the mental chronometry paradigm to examine motor imagery ability. The main objective of the current review is to collate these stu

  6. Current insights in the development of children's motor imagery ability.

    NARCIS (Netherlands)

    Spruijt, S.; Kamp, J. van der; Steenbergen, B.

    2015-01-01

    Over the last two decades, the number of studies on motor imagery in children has witnessed a large expansion. Most studies used the hand laterality judgment paradigm or the mental chronometry paradigm to examine motor imagery ability. The main objective of the current review is to collate these stu

  7. Tiling by rectangles and alternating current

    KAUST Repository

    Prasolov, M. V.

    2011-04-01

    This paper is on tilings of polygons by rectangles. A celebrated physical interpretation of such tilings by R.L. Brooks, C.A.B. Smith, A.H. Stone and W.T. Tutte uses direct-current circuits. The new approach of this paper is an application of alternating-current circuits. The following results are obtained: •a necessary condition for a rectangle to be tilable by rectangles of given shapes;•a criterion for a rectangle to be tilable by rectangles similar to it but not all homothetic to it;•a criterion for a "generic" polygon to be tilable by squares. These results generalize those of C. Freiling, R. Kenyon, M. Laczkovich, D. Rinne, and G. Szekeres. © 2010 Elsevier Inc.

  8. The causes and effects of the Alternative Motor Fuels Act

    Science.gov (United States)

    Liu, Yimin

    The corporate average fuel economy (CAFE) standard is the major policy tool to improve the fleet average miles per gallon of automobile manufacturers in the U.S. The Alternative Motor Fuels Act (AMFA) provides special treatment in calculating the fuel economy of alternative fuel vehicles to give manufacturers CAFE incentives to produce more alternative fuel vehicles. AMFA has as its goals an increase in the production of alternative fuel vehicles and a decrease in gasoline consumption and greenhouse gas emissions. This dissertation examines theoretically the effects of the program set up under AMFA. It finds that, under some conditions, this program may actually increase gasoline consumption and greenhouse gas emissions. The dissertation also uses hedonic techniques to examine whether the Alternative Motor Fuels Act (AMFA) has a significant effect on the implicit price of fuel economy and whether the marginal value of vehicle fuel efficiency changes over time. It estimates the change of implicit price in miles per gallon after the production of alternative fuel vehicles (AFVs). Results indicate that every year consumers may evaluate vehicle fuel economy differently, and that since AFVs came to the market, the marginal value of fuel economy from specific companies producing AFVs has decreased. This finding suggests that since the AMFA provides extra Corporate Average Fuel Economy (CAFE) credit for those automakers producing AFVs, the automakers can take advantage of the incentive to produce more profitable conventional vehicles and meet CAFE standards without improving the fleet fuel economy. In this way, manufacturers who produce AFVs are willing to offer a lower price for the fuel economy under the AMFA. Additionally, this paper suggests that the flexible fuel vehicles (FFVs) on the market are not significantly more expensive than comparable conventional vehicles, even if FFVs are also able to run on an alternative fuel and may cost more than conventional vehicles

  9. Motor current signature analysis for determining operational readiness of motor-operated valves (MOVs)

    International Nuclear Information System (INIS)

    Motor current signature analysis (MCSA) is a novel diagnostic process for condition monitoring of electric-motor-driven mechanical equipment (e.g., pumps, motor-operated valves, compressors, and processing machinery). The MCSA process identifies, characterizes, and trends over time the instantaneous load variations of mechanical equipment in order to diagnose changes in the condition of the equipment (e.g., due to degradation or service wear), which, if allowed to continue, may lead to failure. It monitors the instantaneous variations (noise content) in the electric current flowing through the power leads to the electric motor that drives the equipment. The motor itself thereby acts as a transducer, sensing both large and small, long-term and rapid, mechanical load variations and converting them to variations in the induced current generated in the motor windings. This motor current noise signature is detected, amplified, and further processed as needed to examine its time domain and frequency domain (spectral) characteristics. The operational principles of MCSA and the nonintrusive data collection apparatus and procedure used with MOVs will be described. Data collected from MOVs in both laboratory and in-plant environments will also be shown to illustrate the ability of MCSA to ''see'' the detailed inner workings of the valve and operator and thus to detect degraded performance at an incipient stage. (Set of 18 vugraphs)

  10. Advanced analysis technique for the evaluation of linear alternators and linear motors

    Science.gov (United States)

    Holliday, Jeffrey C.

    1995-01-01

    A method for the mathematical analysis of linear alternator and linear motor devices and designs is described, and an example of its use is included. The technique seeks to surpass other methods of analysis by including more rigorous treatment of phenomena normally omitted or coarsely approximated such as eddy braking, non-linear material properties, and power losses generated within structures surrounding the device. The technique is broadly applicable to linear alternators and linear motors involving iron yoke structures and moving permanent magnets. The technique involves the application of Amperian current equivalents to the modeling of the moving permanent magnet components within a finite element formulation. The resulting steady state and transient mode field solutions can simultaneously account for the moving and static field sources within and around the device.

  11. A methodology for assessing the market benefits of alternative motor fuels: The Alternative Fuels Trade Model

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, P.N.

    1993-09-01

    This report describes a modeling methodology for examining the prospective economic benefits of displacing motor gasoline use by alternative fuels. The approach is based on the Alternative Fuels Trade Model (AFTM). AFTM development was undertaken by the US Department of Energy (DOE) as part of a longer term study of alternative fuels issues. The AFTM is intended to assist with evaluating how alternative fuels may be promoted effectively, and what the consequences of substantial alternative fuels use might be. Such an evaluation of policies and consequences of an alternative fuels program is being undertaken by DOE as required by Section 502(b) of the Energy Policy Act of 1992. Interest in alternative fuels is based on the prospective economic, environmental and energy security benefits from the substitution of these fuels for conventional transportation fuels. The transportation sector is heavily dependent on oil. Increased oil use implies increased petroleum imports, with much of the increase coming from OPEC countries. Conversely, displacement of gasoline has the potential to reduce US petroleum imports, thereby reducing reliance on OPEC oil and possibly weakening OPEC`s ability to extract monopoly profits. The magnitude of US petroleum import reduction, the attendant fuel price changes, and the resulting US benefits, depend upon the nature of oil-gas substitution and the supply and demand behavior of other world regions. The methodology applies an integrated model of fuel market interactions to characterize these effects.

  12. Two alternating motor programs drive navigation in Drosophila larva.

    Directory of Open Access Journals (Sweden)

    Subhaneil Lahiri

    Full Text Available When placed on a temperature gradient, a Drosophila larva navigates away from excessive cold or heat by regulating the size, frequency, and direction of reorientation maneuvers between successive periods of forward movement. Forward movement is driven by peristalsis waves that travel from tail to head. During each reorientation maneuver, the larva pauses and sweeps its head from side to side until it picks a new direction for forward movement. Here, we characterized the motor programs that underlie the initiation, execution, and completion of reorientation maneuvers by measuring body segment dynamics of freely moving larvae with fluorescent muscle fibers as they were exposed to temporal changes in temperature. We find that reorientation maneuvers are characterized by highly stereotyped spatiotemporal patterns of segment dynamics. Reorientation maneuvers are initiated with head sweeping movement driven by asymmetric contraction of a portion of anterior body segments. The larva attains a new direction for forward movement after head sweeping movement by using peristalsis waves that gradually push posterior body segments out of alignment with the tail (i.e., the previous direction of forward movement into alignment with the head. Thus, reorientation maneuvers during thermotaxis are carried out by two alternating motor programs: (1 peristalsis for driving forward movement and (2 asymmetric contraction of anterior body segments for driving head sweeping movement.

  13. Alternating Current Influences Anaerobic Electroactive Biofilm Activity.

    Science.gov (United States)

    Wang, Xin; Zhou, Lean; Lu, Lu; Lobo, Fernanda Leite; Li, Nan; Wang, Heming; Park, Jaedo; Ren, Zhiyong Jason

    2016-09-01

    Alternating current (AC) is known to inactivate microbial growth in suspension, but how AC influences anaerobic biofilm activities has not been systematically investigated. Using a Geobacter dominated anaerobic biofilm growing on the electrodes of microbial electrochemical reactors, we found that high frequency AC ranging from 1 MHz to 1 kHz (amplitude of 5 V, 30 min) showed only temporary inhibition to the biofilm activity. However, lower frequency (100 Hz, 1.2 or 5 V) treatment led to 47 ± 19% permanent decrease in limiting current on the same biofilm, which is attributed to the action of electrohydrodynamic force that caused biofilm damage and loss of intercellular electron transfer network. Confocal microscopy images show such inactivation mainly occurred at the interface between the biofilm and the electrode. Reducing the frequency further to 1 Hz led to water electrolysis, which generated gas bubbles that flushed all attached cells out of the electrode. These findings provide new references on understanding and regulating biofilm growth, which has broader implications in biofouling control, anaerobic waste treatment, energy and product recovery, and general understanding of microbial ecology and physiology. PMID:27485403

  14. Brushless DC motor Drive during Speed regulation with Current Controller

    Directory of Open Access Journals (Sweden)

    Bhikshalu Manchala

    2015-04-01

    Full Text Available Brushless DC Motor (BLDC is one of the best electrical drives that have increasing popularity, due to their high efficiency, reliability, good dynamic response and very low maintenance. Due to the increasing demand for compact & reliable motors and the evolution of low cost power semiconductor switches and permanent magnet (PM materials, brushless DC motors become popular in every application from home appliances to aerospace industry. The conventional techniques for controlling the stator phase current in a brushless DC drive are practically effective in low speed and cannot reduce the commutation torque ripple in high speed range. This paper presents the PI controller for speed control of BLDC motor. The output of the PI controllers is summed and is given as the input to the current controller. The BLDC motor is fed from the inverter where the rotor position and current controller is the input. The complete model of the proposed drive system is developed and simulated using MATLAB/Simulink software. The operation principle of using component is analysed and the simulation results are presented in this to verify the theoretical analysis.

  15. Advanced induction motor drive control with single current sensor

    Directory of Open Access Journals (Sweden)

    Adžić Evgenije M.

    2016-01-01

    Full Text Available This paper proposes induction motor drive control method which uses minimal number of sensors, providing only DC-link current as a feedback signal. Improved DC-link current sampling scheme and modified asymmetrical switching pattern cancels characteristic waveform errors which exist in all three reconstructed motor line-currents. Motor linecurrent harmonic content is reduced to an acceptable level, eliminating torque and speed oscillations which were inherent for conventional single sensor drives. Consequently, use of single current sensor and line-current reconstruction technique is no longer acceptable only for low and medium performance drives, but also for drives where priority is obtaining a highly accurate, stable and fast response. Proposed control algorithm is validated using induction motor drive hardware prototype based on TMS320F2812 digital signal processor. [Projekat Ministarstva nauke Republike Srbije, br. III 042004 and by the Provincial Secretariat for Science and Technological Development of AP Vojvodina under contract No. 114-451-3508/2013-04

  16. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well without...... further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as on the actual induction motor, both in open-loop current control and when an outer speed control loop...

  17. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2001-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is then constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well...... without further complications. The synthesis method is applied to the model, yielding an LPV discrete-time controller. Finally, the efficiency of the control scheme is validated via simulations as well as experimentally on the actual induction motor, both in open-loop current control and when an outer...

  18. ESTIMATION OF THE MAIN CHARACTERISTICS OF THE TRACTION BLDC MOTOR ON THE BASIS OF VEHICLE ALTERNATOR

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2014-10-01

    Full Text Available A method of estimation of basic parameters of the BLDC motor based on the vehicle powerful alternator to convert an ordinary vehicle into a hybrid one is offered. The results of estimation of basic characteristics of the electric motor on the basis of the automobile alternator G290 are presented.

  19. Experimental setup for the measurement of induction motor cage currents

    International Nuclear Information System (INIS)

    An experimental setup for measurement of the currents flowing in the rotor bars of induction motors during synchronous no-load tests is described in the paper. The experimental verification of the high-frequency phenomena in the rotor cage is fundamental for a deep insight of the additional loss estimation by numerical methods. The attention is mainly focused on the analysis and design of the transducers developed for the cage current measurement

  20. Discrete-Time LPV Current Control of an Induction Motor

    DEFF Research Database (Denmark)

    Bendtsen, Jan Dimon; Trangbæk, Klaus

    2003-01-01

    In this paper we apply a new method for gain-scheduled output feedback control of nonlinear systems to current control of an induction motor. The method relies on recently developed controller synthesis results for linear parameter-varying (LPV) systems, where the controller synthesis is formulated...... as a set of linear matrix inequalities with full-block multipliers. A standard nonlinear model of the motor is constructed and written on LPV form. We then show that, although originally developed in continuous time, the controller synthesis results can be applied to a discrete-time model as well...

  1. Overview of current and alternative slaughter practices

    Directory of Open Access Journals (Sweden)

    Troeger K.

    2004-01-01

    Full Text Available The conventional cattle slaughtering process includes some critical stages where a dissemination of Specified Risk Material (SRM: brain, spinal cord within or onto the carcass and within the slaughterhouse environment can occur. These processes are captive bolt stunning, removal of the head and first of all carcass splitting (sawing the spine lengthways. Captive bolt (CB stunning results in massive brain tissue damage with bleeding, and in some cases brain tissue also emerges from the CB hole. As the heart is still functioning, there is a risk of brain tissue particles being transferred v i a the blood flow to heart and lungs or even in the whole carcass. This contamination risk is actually assessed to be low, but a continuing leakage of Central Nervous System (CNS material from the captive bolt aperture in the further slaughter process may lead to direct and indirect contamination of carcass, meat and equipment. Therefore alternative stunning methods like electrical stunning or concussion stunning are discussed. A further critical point is the treatment of the head. When the head is removed, the spinal cord is cut with a knife. There is a danger of cross contamination due to spinal protein that may adhere to the knife and because of liquid cerebralis, which leaks from the foramen occipitale magnum. Further head cleaning with hand-held hoses following skinning also includes the danger of cross contamination from cleaning water or aerosol. Therefore measures regarding the safe handling of head and harvesting of head meat are proposed. The most critical point in terms of contamination of the meat surface with SRM is the currently common practise of sawing the spine vertically in the middle with hand-guided belt-type saws. A m i x t u r e of sawing residues and rinsing water (“sawing sludge” collects in the housing of the saw, and if it contains infectious material this leads to contamination of the subsequent carcasses. The most promising

  2. The Use of Current Generators in Electrical Converter Drives for Stepper Motors

    Directory of Open Access Journals (Sweden)

    Emanoil Toma

    2014-09-01

    Full Text Available This paper presents some ways to realize electrical converters for stepper motor drives. The first part analyzes aspects for unipolar stepper motor and use of constant current generators. The second part present current sources based on peak limiting current trough the inductance of motor coil. A complete drive module for bipolar stepper motor was conceived and simulation results confirm their functionability.

  3. Discrete Current Control Strategy of Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Yan Dong

    2013-01-01

    Full Text Available A control strategy of permanent magnet synchronous motors (PMSMs, which is different from the traditional vector control (VC and direct torque control (DTC, is proposed. Firstly, the circular rotating magnetic field is analyzed on the simplified model and discredited into stepping magnetic field. The stepping magnetomotive force will drive the rotor to run as the stepping motor. Secondly, the stator current orientation is used to build the control model instead of rotor flux orientation. Then, the discrete current control strategy is set and adopted in positioning control. Three methods of the strategy are simulated in computer and tested on the experiment platform of PMSM. The control precision is also verified through the experiment.

  4. Development of Rotor Diagnosis Method via Motor Current Signature Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Seok; Huh, Hyung; Kim, Min Hwan; Jeong, Kyeong Hoon; Lee, Gyu Mhan; Park, Jin Ho; Park, Keun Bae; Lee, Cheol Kwon; Hur, S

    2006-01-15

    A study on motor current signature analysis has been performed to monitor a journal bearing fault due to increasing clearance. It was known that the journal bearing clearance produces side band frequencies, the supplied current frequency plus and minus rotational rotor frequency in motor current. But the existence information of the side band frequencies is not sufficient to diagnose whether the journal bearing is safe or not. Four journal bearing sets with different clearances are used to measure the side band frequency amplitude and the rotor vibration amplitude versus the journal bearing clearance. The side band frequency amplitude and the rotor vibration amplitude are increased as the journal bearing clearance is increasing. This trend assures that ASME OM vibration guide line can be applied to estimate the journal bearing clearance size. In this research, 2.5 times the reference side band amplitude is suggested as an indicator of a journal bearing fault. Further study is necessary to make out more specific quantitative relations between the side band frequency amplitude and the journal bearing clearance of a motor.

  5. Method of measuring direct and alternating currents with galvanic decoupling

    Energy Technology Data Exchange (ETDEWEB)

    Provotorov, I.V.; Simakov, S.R.; Che En Un

    1995-09-01

    A method is described for measuring direct and alternating microcurrents with galvanic decoupling. The method is based on the dependence of the current drawn by an operational amplifier circuit on the current measured. The measuring circuit is galvanically decoupled by a transformer which also supplies the power for the electronics. The error of measurement is less than 0.4% for direct current and 0.8% for alternating currents in the frequency band 20 Hz to 10 kHz.

  6. 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.

  7. Application of electric current signature analysis for three-phase induction motors

    International Nuclear Information System (INIS)

    As the motor's supply current changes with the load behavior, it is possible to analyze the motor condition through motor current signal analysis (MCSA). This paper examined the problem of the detection of the mechanical failures of the motor and its connected gear. From the result of the tests, the MCSA method is effective to monitor the dynamic model composed of motors and gear shaft. (author)

  8. Primer on Motor Fuel Excise Taxes and the Role of Alternative Fuels and Energy Efficient Vehicles

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alex [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2015-08-26

    Motor fuel taxes were established to finance our nation’s transportation infrastructure, yet evolving economic, political, and technological influences are constraining this ability. At the federal level, the Highway Trust Fund (HTF), which is primarily funded by motor fuel taxes, has become increasingly dependent on general fund contributions and short-term reauthorizations to prevent insolvency. As a result, there are discussions at both the federal and state levels in which stakeholders are examining the future of motor fuel excise taxes as well as the role of electric and alternative fuel vehicles in that future. On July 1, 2015, six states increased their motor fuel tax rates.

  9. Dynamics of laser-guided alternating current high voltage discharges

    Science.gov (United States)

    Daigle, J.-F.; Théberge, F.; Lassonde, P.; Kieffer, J.-C.; Fujii, T.; Fortin, J.; Châteauneuf, M.; Dubois, J.

    2013-10-01

    The dynamics of laser-guided alternating current high voltage discharges are characterized using a streak camera. Laser filaments were used to trigger and guide the discharges produced by a commercial Tesla coil. The streaking images revealed that the dynamics of the guided alternating current high voltage corona are different from that of a direct current source. The measured effective corona velocity and the absence of leader streamers confirmed that it evolves in a pure leader regime.

  10. Submerged electricity generation plane with marine current-driven motors

    Energy Technology Data Exchange (ETDEWEB)

    Dehlsen, James G.P.; Dehlsen, James B.; Fleming, Alexander

    2014-07-01

    An underwater apparatus for generating electric power from ocean currents and deep water tides. A submersible platform including two or more power pods, each having a rotor with fixed-pitch blades, with drivetrains housed in pressure vessels that are connected by a transverse structure providing buoyancy, which can be a wing depressor, hydrofoil, truss, or faired tube. The platform is connected to anchors on the seafloor by forward mooring lines and a vertical mooring line that restricts the depth of the device in the water column. The platform operates using passive, rather than active, depth control. The wing depressor, along with rotor drag loads, ensures the platform seeks the desired operational current velocity. The rotors are directly coupled to a hydraulic pump that drives at least one constant-speed hydraulic-motor generator set and enables hydraulic braking. A fluidic bearing decouples non-torque rotor loads to the main shaft driving the hydraulic pumps.

  11. 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.

  12. Second interim report of the Interagency Commission on Alternative Motor Fuels

    International Nuclear Information System (INIS)

    This report describes progress the commission and government agencies have made in implementing the provisions of the Alternative Motor Fuels Act of 1988, assessing the role of alternative motor fuels in the US transportation sector, and developing policies to promote the use of alternative fuels. The alternative motor-fuels policies proposed in the National Energy Strategy (NES) are described and shows how they compose an effective long-term plan to encourage the widespread use of alternative motor fuels. The progress to date of the Department of Energy (DOE) and other agencies in implementing the programs required by the AMFA is reported. A detailed scenario of future alternative-fuel use that displaces 2.5 million barrels per day (MMBD) of petroleum and a feasible path of vehicle production and fuel supply leading to that goal is described. An analytical tool for exploring and quantifying the energy market impacts of alternative fuels, the Alternative Fuels Trade Model (AFTM), is described. The AFTM provides a means of investigating the impacts of alternative fuels in interrelated world energy markets for petroleum and natural gas. Several major initiatives have recently been enacted that have important ramifications for alternative-fuels policy. The Clean Air Act Amendments of 1990 contain provisions mandating the use of nonpetroleum oxygenates in reformulated gasoline. Other provisions for much more stringent emissions standards may affect the ability of manufacturers to make and sell conventional-fuel vehicles or, at the very least, affect their cost-effectiveness in comparison to cleaner alternative-fuel vehicles (AFV's). Finally, the key areas in which technological advances could substantially improve the competitiveness of AFV technologies in the marketplace are reviewed

  13. Current insights in the development of children’s motor imagery ability

    Directory of Open Access Journals (Sweden)

    Steffie eSpruijt

    2015-06-01

    Full Text Available Over the last two decades, the number of studies on motor imagery in children has witnessed a large expansion. Most studies used the hand laterality judgment paradigm or the mental chronometry paradigm to examine motor imagery ability. The main objective of the current review is to collate these studies to provide a more comprehensive insight in children’s motor imagery development and its age of onset. Motor imagery is a form of motor cognition and aligns with forward (or predictive models of motor control. Studying age-related differences in motor imagery ability in children therefore provides insight in underlying processes of motor development during childhood. Another motivation for studying age-related differences in motor imagery is that in order to effectively apply motor imagery training in children (with motor impairments, it is pertinent to first establish the age at which children are actually able to perform motor imagery.Overall, performance in the imagery tasks develops between 5 and 12 years of age. The age of motor imagery onset, however, remains equivocal, as some studies indicate that children of 5 to 7 years old can already enlist motor imagery in an implicit motor imagery task, whereas other studies using explicit instructions revealed that children do not use motor imagery before the age of 10. From the findings of the current study, we can conclude that motor imagery training is potentially a feasible method for paediatric rehabilitation in children from 5 years on. We suggest that younger children are most likely to benefit from motor imagery training that is presented in an implicit way. Action observation training might be a beneficial adjunct to implicit motor imagery training. From 10 years of age, more explicit forms of motor imagery training can be effectively used.

  14. Spontaneously Fluctuating Motor Cortex Excitability in Alternating Hemiplegia of Childhood: A Transcranial Magnetic Stimulation Study

    Science.gov (United States)

    Stern, William M.; Desikan, Mahalekshmi; Hoad, Damon; Jaffer, Fatima; Strigaro, Gionata; Sander, Josemir W.; Rothwell, John C.; Sisodiya, Sanjay M.

    2016-01-01

    Background Alternating hemiplegia of childhood is a very rare and serious neurodevelopmental syndrome; its genetic basis has recently been established. Its characteristic features include typically-unprovoked episodes of hemiplegia and other transient or more persistent neurological abnormalities. Methods We used transcranial magnetic stimulation to assess the effect of the condition on motor cortex neurophysiology both during and between attacks of hemiplegia. Nine people with alternating hemiplegia of childhood were recruited; eight were successfully tested using transcranial magnetic stimulation to study motor cortex excitability, using single and paired pulse paradigms. For comparison, data from ten people with epilepsy but not alternating hemiplegia, and ten healthy controls, were used. Results One person with alternating hemiplegia tested during the onset of a hemiplegic attack showed progressively diminishing motor cortex excitability until no response could be evoked; a second person tested during a prolonged bilateral hemiplegic attack showed unusually low excitability. Three people tested between attacks showed asymptomatic variation in cortical excitability, not seen in controls. Paired pulse paradigms, which probe intracortical inhibitory and excitatory circuits, gave results similar to controls. Conclusions We report symptomatic and asymptomatic fluctuations in motor cortex excitability in people with alternating hemiplegia of childhood, not seen in controls. We propose that such fluctuations underlie hemiplegic attacks, and speculate that the asymptomatic fluctuation we detected may be useful as a biomarker for disease activity. PMID:26999520

  15. Modeling and Simulation of Current Source Inverter Fed Synchronous Motor in Complex Frequency Domain Taking the Transition Zone From Induction Motor to Synchronous Motor Mode into Account

    Directory of Open Access Journals (Sweden)

    A.B. Chattopadhyay

    2014-02-01

    Full Text Available Modeling of synchronous motor plays a dominant role in designing complicated drive system for different applications, especially large blower fans etc for steel industries. As synchronous motor has no inherent starting torque generally it is started as an induction motor with the help of a damper winding and it pulls into synchronism under certain conditions. The present paper exactly concentrates on this particular zone of transition from induction motor to synchronous motor mode for a current source inverter fed synchronous motor drive system. Due to complexity of synchronous motor in terms of number of windings and finite amount of air gap saliency, direct modeling of such transition zone in time domain becomes cumbersome at the first instance of modeling. That is why the modeling in complex frequency domain (s-domain has been taken up using small perturbation model. Such a model clearly shows role of induction motor as noise function or disturbance function with respect to the open loop block diagram of synchronous motor. Such finding can be quantized in terms of important results and that is done in the present paper such that the results can help the designer for the successful design of a synchronous motor drive system.

  16. THE FUTURE OF MOTOR TRANSPORT – ALTERNATIVE FUEL AND CANCEROGENIC SAFETY

    Directory of Open Access Journals (Sweden)

    Kanilo, P.

    2012-06-01

    Full Text Available Prospects of application of synthetic hydrocarbonic motor fuels and hydrogen as the basic and additional energy carriers are analysed. It is shown that the use of alternative fuels does not only effectively replaces oil fuel, but also provides essential decrease of environmental contamination by supertoxic substancses, namely cancerogenic and mutagen.

  17. 77 FR 33315 - Protection of Stratospheric Ozone: Alternative for the Motor Vehicle Air Conditioning Sector...

    Science.gov (United States)

    2012-06-06

    ... Air Conditioning Sector Under the Significant New Alternatives Policy (SNAP) Program AGENCY...) within the refrigeration and air-conditioning sector. This final rule only concerns the use of CO 2 in... their suppliers with a refrigerant option subject to use conditions for motor vehicle air...

  18. Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The Brushless Direct Current (BLDC) motor is widely used in aerospace area, CNC machines and servo systems that require the high control accuracy Once the faults occur in the motor, it will cause great damage to the whole system. Mechanical faults are common in electric machines, and account for up to 50%-60% of the faults. Approximately, 80% of the mechanical faults lead to the eccentricity. So it is necessary to monitor the health condition of the motor to ensure the faults can be detected earlier and measures will be taken to imorove the reliability.

  19. Current status of gene therapy for motor neuron disease

    Institute of Scientific and Technical Information of China (English)

    Xingkai An; Rong Peng; Shanshan Zhao

    2006-01-01

    OBJECTIVE: Although the etiology and pathogenesis of motor neuron disease is still unknown, there are many hypotheses on motor neuron mitochondrion, cytoskeleton structure and functional injuries. Thus, gene therapy of motor neuron disease has become a hot topic to apply in viral vector, gene delivery and basic gene techniques.DATA SOURCES: The related articles published between January 2000 and October 2006 were searched in Medline database and ISl database by computer using the keywords "motor neuron disease, gene therapy", and the language is limited to English. Meanwhile, the related references of review were also searched by handiwork. STUDY SELECTION: Original articles and referred articles in review were chosen after first hearing, then the full text which had new ideas were found, and when refer to the similar study in the recent years were considered first.DATA EXTRACTION: Among the 92 related articles, 40 ones were accepted, and 52 were excluded because of repetitive study or reviews.DATA SYNTHESIS: The viral vectors of gene therapy for motor neuron disease include adenoviral, adeno-associated viral vectors, herpes simplex virus type 1 vectors and lentiviral vectors. The delivery of them can be achieved by direct injection into the brain, or by remote delivery after injection vectors into muscle or peripheral nerves, or by ex vivo gene transfer. The viral vectors of gene therapy for motor neuron disease have been successfully developed, but the gene delivery of them is hampered by some difficulties. The RNA interference and neuroprotection are the main technologies for gene-based therapy in motor neuron disease. CONCLUSION : The RNA interference for motor neuron disease has succeeded in animal models, and the neuroprotection also does. But, there are still a lot of questions for gene therapy in the clinical treatment of motor neuron disease.

  20. A Hydraulic Motor-Alternator System for Ocean-Submersible Vehicles

    Science.gov (United States)

    Aintablian, Harry O.; Valdez, Thomas I.; Jones, Jack A.

    2012-01-01

    An ocean-submersible vehicle has been developed at JPL that moves back and forth between sea level and a depth of a few hundred meters. A liquid volumetric change at a pressure of 70 bars is created by means of thermal phase change. During vehicle ascent, the phase-change material (PCM) is melted by the circulation of warm water and thus pressure is increased. During vehicle descent, the PCM is cooled resulting in reduced pressure. This pressure change is used to generate electric power by means of a hydraulic pump that drives a permanent magnet (PM) alternator. The output energy of the alternator is stored in a rechargeable battery that powers an on-board computer, instrumentation and other peripherals.The focus of this paper is the performance evaluation of a specific hydraulic motor-alternator system. Experimental and theoretical efficiency data of the hydraulic motor and the alternator are presented. The results are used to evaluate the optimization of the hydraulic motor-alternator system. The integrated submersible vehicle was successfully operated in the Pacific Ocean near Hawaii. A brief overview of the actual test results is presented.

  1. The Mechanism Study of Alternating Arc(AC)Magnetic Levitation Induction Motor

    OpenAIRE

    Li Zeng; Fan Zhang; Zhida Zhu; Fang Chen

    2015-01-01

    Magnetic levitation (no bearings) motor by using magnetic force to make rotor suspend and drive realize its high or ultra-high speed rotating. The stator’s structure of traditional no bearing magnetic levitation motor is double winding which is polar logarithmic difference 1 of 2 sets of winding (torque winding and suspension winding) and embedded in the stator. Using two inverter respectively for the two sets of winding to go into the same frequency current in order to realize the suspension...

  2. Alternating current organic light emitting diodes based on polymer heterojunction

    Institute of Scientific and Technical Information of China (English)

    Yewen Jiang(蒋业文); Haishu Tan(谭海曙); Jianquan Yao(姚建铨)

    2003-01-01

    Most alternating current (ac) polymer EL (electroluminescent) devices to date are based on symmetricalstructure. Here novel alternating current EL devices with asymmetric structure are successfully fabricatedby using a hole type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and an electrontype polymer PPQ [poly (phenyl quinoxaline)]. We report that performance of polymer devices withheterojunction in ac operation is not so sensitive to thickness of the two polymer layers as in direct current(dc) operation. This new advantage of ac operation mode over dc means easy production and cheapfacilities in large-scale production in the near future. Different emission spectra are obtained when ourac devices operate in ac mode, forward and reverse bias. Emission spectrum at reverse bias includes twoparts: one is from PDDOPV, the other is from PPQ.

  3. Study on Current Sensorless Vector Control Method for Electric Vehicle Drive Motor

    Directory of Open Access Journals (Sweden)

    Xiaoyong Shen

    2013-07-01

    Full Text Available With the aggravation of environment pollution and the reduction of petroleum resources, the development of electric vehicle (EV draws more and more people’s attention. In the EV research field, that seeking for a high efficient and reliable motor control method that suits the operating conditions and characteristics of the vehicle drive motor has become one of the key techniques that need to be broken through urgently. Owing to the problems that the efficient work area is narrow and it leads to over-current phenomenon when traditional motor vector control method is applied to vehicle drive motor, this paper presents a current sensorless vector control technique for electric vehicle drive motor. According to motor speed and command torque which is gained from the speed loop control, this method directly controls the magnitude and phase angle of voltage vector to realize the orientation control of the magnetic field and then achieve the purpose of controlling the motor torque and speed. The feasibility and effectiveness of this method are verified by simulation results and bench test. Moreover, this method can not only improve the efficient work area, but also increase the reliability of motor control system. At the same time, it overcomes the dependence on the current sensor, circumvents the over-current defect caused by traditional motor vector control approach and reduces its cost. So it is a suitable and efficient control method for electric vehicle drive motor.  

  4. ELECTRIC MOTOR DIAGNOSTICS OF SWITCHES BASED ON THE NEURAL NETWORK DATA MODELING THE SPECTRAL DECOMPOSITION OF THE CURRENTS

    Directory of Open Access Journals (Sweden)

    O. M. Shvets

    2009-07-01

    Full Text Available The method of automated diagnostics of electric motors is offered. It uses a neural network revealing the electric motor faults on the basis of analysis of frequency spectrum of current flowing through the motor.

  5. The Mechanism Study of Alternating Arc(ACMagnetic Levitation Induction Motor

    Directory of Open Access Journals (Sweden)

    Li Zeng

    2015-01-01

    Full Text Available Magnetic levitation (no bearings motor by using magnetic force to make rotor suspend and drive realize its high or ultra-high speed rotating. The stator’s structure of traditional no bearing magnetic levitation motor is double winding which is polar logarithmic difference 1 of 2 sets of winding (torque winding and suspension winding and embedded in the stator. Using two inverter respectively for the two sets of winding to go into the same frequency current in order to realize the suspension of the rotor and motor’s driven, small carrying capacity of motor’s structure, controlling complex system. This paper based on the traditional motor technology puts forward a kind of arc principle and respectively decorates two arc motors in horizontal and vertical direction symmetric to rotor according to the electromagnetic bearing suspension technology that is constituted the arc magnetic levitation induction motor. Establishing air-gap transformation regular between rotor and stator (air-gap length motor is under the effect of interference. Based on the electromagnetic theory establishing distribution regular of the air-gap magnetic induction intensity. Virtual displacement principle is used to establish electromagnetism mathematical model and motor electromagnetism levitation. By the finite element analysis carrying on simulation research to the magnetic induction intensity, electric magnetic levitation force and distribution features of electromagnetic torque and so on.

  6. MICROPROCESSOR-BASED PROTECTION DEVICE ELECTRIC MOTORS AGAINST SHORT CIRCUIT CURRENTS

    OpenAIRE

    D. V. Ustymenko

    2010-01-01

    The microprocessor device of protection of electric chains of electric motors from short circuit currents, in which switching-off of a short circuit current is carried out before it achieves a shock value, is presented.

  7. How Transcranial Direct Current Stimulation Can Modulate Implicit Motor Sequence Learning and Consolidation: A Brief Review.

    Science.gov (United States)

    Savic, Branislav; Meier, Beat

    2016-01-01

    The purpose of this review is to investigate how transcranial direct current stimulation (tDCS) can modulate implicit motor sequence learning and consolidation. So far, most of the studies have focused on the modulating effect of tDCS for explicit motor learning. Here, we focus explicitly on implicit motor sequence learning and consolidation in order to improve our understanding about the potential of tDCS to affect this kind of unconscious learning. Specifically, we concentrate on studies with the serial reaction time task (SRTT), the classical paradigm for measuring implicit motor sequence learning. The influence of tDCS has been investigated for the primary motor cortex, the premotor cortex, the prefrontal cortex, and the cerebellum. The results indicate that tDCS above the primary motor cortex gives raise to the most consistent modulating effects for both implicit motor sequence learning and consolidation. PMID:26903837

  8. How transcranial direct current stimulation can modulate implicit motor sequence learning and consolidation: A brief review

    Directory of Open Access Journals (Sweden)

    Branislav eSavic

    2016-02-01

    Full Text Available The purpose of this review is to investigate how transcranial direct current stimulation (tDCS can modulate implicit motor sequence learning and consolidation. So far, most of the studies have focused on the modulating effect of tDCS for explicit motor learning. Here, we focus explicitly on implicit motor sequence learning and consolidation in order to improve our understanding about the potential of tDCS to affect this kind of unconscious learning. Specifically, we concentrate on studies with the serial reaction time task (SRTT, the classical paradigm for measuring implicit motor sequence learning. The influence of tDCS has been investigated for the primary motor cortex, the premotor cortex, the prefrontal cortex, and the cerebellum. The results indicate that tDCS above the primary motor cortex gives raise to the most consistent modulating effects for both implicit motor sequence learning and consolidation.

  9. Alternative communication systems for people with severe motor disabilities: a survey

    Directory of Open Access Journals (Sweden)

    Andrade Adriano O

    2011-04-01

    Full Text Available Abstract We have now sufficient evidence that using electrical biosignals in the field of Alternative and Augmented Communication is feasible. Additionally, they are particularly suitable in the case of people with severe motor impairment, e.g. people with high-level spinal cord injury or with locked-up syndrome. Developing solutions for them implies that we find ways to use sensors that fit the user's needs and limitations, which in turn impacts the specifications of the system translating the user's intentions into commands. After devising solutions for a given user or profile, the system should be evaluated with an appropriate method, allowing a comparison with other solutions. This paper submits a review of the way three bioelectrical signals - electromyographic, electrooculographic and electroencephalographic - have been utilised in alternative communication with patients suffering severe motor restrictions. It also offers a comparative study of the various methods applied to measure the performance of AAC systems.

  10. DSPIC BASED POWER ASSISTED STEERING USING BRUSHLESS DIRECT CURRENT MOTOR

    Directory of Open Access Journals (Sweden)

    G. R.P. Lakshmi

    2013-01-01

    Full Text Available This study illustrates the Electrically Assisted power Steering (EAS using BLDC motor for a vehicle. Earlier the Electrically Assisted power Steering (EAS was implemented with DSP. This study shows the usage of a dsPIC to control the BLDC motor with an encoder. The BLDC motor here is driven by dsPIC through a three phase inverter system. IRAMS type of inverter is used which is cost efficient and space efficient. The dsPIC supplied with the input of the steering. In its higher capacity the vehicles speed controller acts as the assistance level controller for steering effort. At the lower capacity, the torque controller gives the effort level control. In reality this can be realized as torque sensor and vehicle sensor interfaced in the dsPIC. For actual implementation in the system, a dsPIC-based BLDC motor controller with three-phase inverter module is used with Hall-effect sensor feedback. It is designed in such a way that the driver assistance can be varied at any time without any difficulty.

  11. Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

    OpenAIRE

    Huangqiu Zhu; Hui Li

    2015-01-01

    Bearingless permanent magnet synchronous motors (BPMSMs), with all advantages of permanent magnet motors (PMSMs) and magnetic bearings, have become an important research direction in the bearingless motor field. To realize a stable suspension for the BPMSM, accurate decoupling control between the electromagnetic torque and radial suspension force is indispensable. In this paper, a concise and reliable analysis method based on a magnetic field equivalent current is presented. By this analysis ...

  12. Influence of Random Potentials on the Current of the Molecular Motor Model

    Institute of Scientific and Technical Information of China (English)

    贾亚; 李家荣

    2001-01-01

    The current of the molecular motor model disturbed by random potentials, which involve the dichotomous and Ornstein-Uhlenbeck potentials, is studied using a finite-space correlation function. It is found that: (i) the amplitude and the correlation length of random potentials play opposing roles in the transport of the molecular motor model; (ii) a random potential with small amplitude and large correlation length is very useful in the molecular motor system.

  13. Transcranial Alternating Current and Random Noise Stimulation: Possible Mechanisms

    Science.gov (United States)

    Antal, Andrea; Herrmann, Christoph S.

    2016-01-01

    Background. Transcranial alternating current stimulation (tACS) is a relatively recent method suited to noninvasively modulate brain oscillations. Technically the method is similar but not identical to transcranial direct current stimulation (tDCS). While decades of research in animals and humans has revealed the main physiological mechanisms of tDCS, less is known about the physiological mechanisms of tACS. Method. Here, we review recent interdisciplinary research that has furthered our understanding of how tACS affects brain oscillations and by what means transcranial random noise stimulation (tRNS) that is a special form of tACS can modulate cortical functions. Results. Animal experiments have demonstrated in what way neurons react to invasively and transcranially applied alternating currents. Such findings are further supported by neural network simulations and knowledge from physics on entraining physical oscillators in the human brain. As a result, fine-grained models of the human skull and brain allow the prediction of the exact pattern of current flow during tDCS and tACS. Finally, recent studies on human physiology and behavior complete the picture of noninvasive modulation of brain oscillations. Conclusion. In future, the methods may be applicable in therapy of neurological and psychiatric disorders that are due to malfunctioning brain oscillations. PMID:27242932

  14. Conventional alternating-current generators and engine generator sets

    Energy Technology Data Exchange (ETDEWEB)

    Segaser, C.L.

    1978-04-01

    Available data and techniques relevant to the selection and analysis of appropriate electrical generating equipment for application in the ICES program are presented. Of the general classes of commercially available a-c generators, the synchronous, rotating field alternator is most suited to ICES applications, and the focus of this technology evaluation. Conventional 60-Hz, alternating-current generators, with standard ratings ranging from 1.25 kVA to 10,000 kVA at voltages from 125 single-phase to 14,400 volts three-phase and speeds up to 1800 rpm are covered. Technical data for representative diesel engine-generator sets for continuous prime power ratings up to 6445 kW are presented. Approximate 1976 costs of standard electrical generating equipment are given for: (1) standard conventional alternating current generators and (2) packaged engine-generator sets. The data indicate a decrease in unit costs as the power ratings increase, with the cost of the slow-speed units somewhat greater than that of the higher speed units. Maintenance data for a typical total energy plant presently in operation indicate that the average cost of maintenance amounts to 41 cents/kWh. A plot of available data also indicates a trend to decreasing operating costs with increasing unit size.

  15. Filtering and Control of High Speed Motor Current in a Flywheel Energy Storage System

    Science.gov (United States)

    Kenny, Barbara H.; Santiago, Walter

    2004-01-01

    The NASA Glenn Research Center has been developing technology to enable the use of high speed flywheel energy storage units in future spacecraft for the last several years. An integral part of the flywheel unit is the three phase motor/generator that is used to accelerate and decelerate the flywheel. The motor/generator voltage is supplied from a pulse width modulated (PWM) inverter operating from a fixed DC voltage supply. The motor current is regulated through a closed loop current control that commands the necessary voltage from the inverter to achieve the desired current. The current regulation loop is the innermost control loop of the overall flywheel system and, as a result, must be fast and accurate over the entire operating speed range (20,000 to 60,000 rpm) of the flywheel. The voltage applied to the motor is a high frequency PWM version of the DC bus voltage that results in the commanded fundamental value plus higher order harmonics. Most of the harmonic content is at the switching frequency and above. The higher order harmonics cause a rapid change in voltage to be applied to the motor that can result in large voltage stresses across the motor windings. In addition, the high frequency content in the motor causes sensor noise in the magnetic bearings that leads to disturbances for the bearing control. To alleviate these problems, a filter is used to present a more sinusoidal voltage to the motor/generator. However, the filter adds additional dynamics and phase lag to the motor system that can interfere with the performance of the current regulator. This paper will discuss the tuning methodology and results for the motor/generator current regulator and the impact of the filter on the control. Results at speeds up to 50,000 rpm are presented.

  16. Correlation analysis of motor current and chatter vibration in grinding using complex continuous wavelet coherence

    Science.gov (United States)

    Liu, Yao; Wang, Xiufeng; Lin, Jing; Zhao, Wei

    2016-11-01

    Motor current is an emerging and popular signal which can be used to detect machining chatter with its multiple advantages. To achieve accurate and reliable chatter detection using motor current, it is important to make clear the quantitative relationship between motor current and chatter vibration, which has not yet been studied clearly. In this study, complex continuous wavelet coherence, including cross wavelet transform and wavelet coherence, is applied to the correlation analysis of motor current and chatter vibration in grinding. Experimental results show that complex continuous wavelet coherence performs very well in demonstrating and quantifying the intense correlation between these two signals in frequency, amplitude and phase. When chatter occurs, clear correlations in frequency and amplitude in the chatter frequency band appear and the phase difference of current signal to vibration signal turns from random to stable. The phase lead of the most correlated chatter frequency is the largest. With the further development of chatter, the correlation grows up in intensity and expands to higher order chatter frequency band. The analyzing results confirm that there is a consistent correlation between motor current and vibration signals in the grinding chatter process. However, to achieve accurate and reliable chatter detection using motor current, the frequency response bandwidth of current loop of the feed drive system must be wide enough to response chatter effectively.

  17. Analysis of torque-current characteristic of brushless DC motor driven by three-phase H-bridge

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents the simulation and analysis of the steady state characteristic of a brushless DC motor studies the torque-current characteristic of the motor as well and discusses the design of a current-measure circuit for torque controlling.

  18. Thin-film Josephson junctions with alternating critical current density

    Science.gov (United States)

    Moshe, Maayan; Kogan, V. G.; Mints, R. G.

    2009-01-01

    We study the field dependence of the maximum current Im(H) in narrow edge-type thin-film Josephson junctions with alternating critical current density. Im(H) is evaluated within nonlocal Josephson electrodynamics taking into account the stray fields that affect the difference of the order-parameter phases across the junction and therefore the tunneling currents. We find that the phase difference along the junction is proportional to the applied field, depends on the junction geometry, but is independent of the Josephson critical current density gc , i.e., it is universal. An explicit form for this universal function is derived for small currents through junctions of the width W≪Λ , the Pearl length. The result is used to calculate Im(H) . It is shown that the maxima of Im(H)∝1/H and the zeros of Im(H) are equidistant but only in high fields. We find that the spacing between zeros is proportional to 1/W2 . The general approach is applied to calculate Im(H) for a superconducting quantum interference device with two narrow edge-type junctions. If gc changes sign periodically or randomly, as it does in grain boundaries of high- Tc materials and superconductor-ferromagnet-superconductor heterostructures, Im(H) not only acquires the major side peaks, but due to nonlocality the following peaks decay much slower than in bulk junctions.

  19. An Alternating Current Electroosmotic Pump Based on Conical Nanopore Membranes.

    Science.gov (United States)

    Wu, Xiaojian; Ramiah Rajasekaran, Pradeep; Martin, Charles R

    2016-04-26

    Electroosmotic flow (EOF) is used to pump solutions through microfluidic devices and capillary electrophoresis columns. We describe here an EOF pump based on membrane EOF rectification, an electrokinetic phenomenon we recently described. EOF rectification requires membranes with asymmetrically shaped pores, and conical pores in a polymeric membrane were used here. We show here that solution flow through the membrane can be achieved by applying a symmetrical sinusoidal voltage waveform across the membrane. This is possible because the alternating current (AC) carried by ions through the pore is rectified, and we previously showed that rectified currents yield EOF rectification. We have investigated the effect of both the magnitude and frequency of the voltage waveform on flow rate through the membrane, and we have measured the maximum operating pressure. Finally, we show that operating in AC mode offers potential advantages relative to conventional DC-mode EOF pumps. PMID:27046145

  20. A Smart Current Modulation Scheme for Harmonic Reduction in Three- Phase Motor Drive Applications

    DEFF Research Database (Denmark)

    Davari, Pooya; Zare, Firuz; Blaabjerg, Frede

    2015-01-01

    harmonic mitigation methods have been developed over the years, the total cost and complexity has become the main obstacle in employing prior-art methods for motor drive systems. This paper presents a novel current modulation method based on the electronic inductor concept for three-phase ac-dc systems......Electric motor-driven systems consume considerable amount of the global electricity. Majority of three-phase motor drives are equipped with conventional diode rectifier and passive harmonic mitigation, being witnessed as the main source in generating input current harmonics. While many active...

  1. Real-time control for long ohmic alternate current discharges

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Ivo S., E-mail: ivoc@ipfn.ist.utl.pt; Duarte, Paulo; Fernandes, Horácio; Valcárcel, Daniel F.; Carvalho, Pedro J.; Silva, Carlos; Duarte, André S.; Neto, André; Sousa, Jorge; Batista, António J.N.; Hekkert, Tiago; Carvalho, Bernardo B.; Gomes, Rui B.

    2014-05-15

    Highlights: • 40 Alternate plasma current (AC) semi-cycles without loss of ionization, more than 1 s of operation. • AC discharges automatic control: feedback loops, time-windows control strategy, goal oriented time-windows and exception handling. • Energy deposition and Carbon radiation evolution during the AC discharges. - Abstract: The ISTTOK tokamak has a long tradition on alternate plasma current (AC) discharges, but the old control system was limiting and lacked full system integration. In order to improve the AC discharges performance the ISTTOK fast control system was updated. This control system developed on site based on the Advanced Telecommunications Computing Architecture (ATCA) standard now integrates the information gathered by all the tokamak real-time diagnostics to produce an accurate observation of the plasma parameters. The real-time actuators were also integrated, allowing a Multiple Input Multiple Output (MIMO) control environment with several synchronization strategies available. The control system software was developed in C++ on top of a Linux system with the Multi-threaded Application Real-Time executor (MARTe) Framework to synchronize the real-time code execution under a 100μs control cycle. In addition, to simplify the discharge programming, a visual Human–Machine Interface (HMI) was also developed using the BaseLib2 libraries included in the MARTe Framework. This paper presents the ISTTOK control system and the optimizations that extended the AC current discharges duration to more than 1 s, corresponding to 40 semi-cycles without apparent degradation of the plasma parameters. This upgrade allows ISTTOK to be used as a low-cost material testing facility with long time exposures to nuclear fusion relevant plasmas, comparable (in duration) with medium size tokamaks.

  2. Diagnosis of cryogenic pump-motor systems using vibration and current signature analysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byeong Keun; Gu, Dong Sik; Kim, Hyo Jung; Jeong, Han Eul [Gyeongsang National University, Tongyoung (Korea, Republic of); Kim, Hak Eun [Korea Gas Technology Corporation, Tongyoung (Korea, Republic of)

    2006-07-15

    In general, to send out natural gas via a pipeline network across the nation in LNG terminal, high-pressure cryogenic pump supply highly compressed LNG to high-pressure vaporization facilities. The Number of cryogenic pumps determined the send-out amount in LNG receiving terminal. So it is main equipment at LNG production process and should be maintained on best conditions. In this paper, to find out the cause of high vibration at cryogenic pumps-motor system in LNG terminal, vibration spectrum analysis and motor current signature analysis have been performed together. Through the analysis, motor rotor bar problems are estimated by the vibration analysis and confirmed by the current analysis. So, it is demonstrated through the case study in this paper, how performing vibration analysis and current signature analysis together can reliable diagnosis rotor bar problems in pump-motor system.

  3. Alternatives to animal testing: current status and future perspectives.

    Science.gov (United States)

    Liebsch, Manfred; Grune, Barbara; Seiler, Andrea; Butzke, Daniel; Oelgeschläger, Michael; Pirow, Ralph; Adler, Sarah; Riebeling, Christian; Luch, Andreas

    2011-08-01

    On the occasion of the 20th anniversary of the Center for Alternative Methods to Animal Experiments (ZEBET), an international symposium was held at the German Federal Institute for Risk Assessment (BfR) in Berlin. At the same time, this symposium was meant to celebrate the 50th anniversary of the publication of the book "The Principles of Humane Experimental Technique" by Russell and Burch in 1959 in which the 3Rs principle (that is, Replacement, Reduction, and Refinement) has been coined and introduced to foster the development of alternative methods to animal testing. Another topic addressed by the symposium was the new vision on "Toxicology in the twenty-first Century", as proposed by the US-National Research Council, which aims at using human cells and tissues for toxicity testing in vitro rather than live animals. An overview of the achievements and current tasks, as well as a vision of the future to be addressed by ZEBET@BfR in the years to come is outlined in the present paper. PMID:21607681

  4. Alternating-current relaxation of a rotating metallic particle

    Science.gov (United States)

    Guo-Xi, Nie; Wen-Jia, Tian; Ji-Ping, Huang; Guo-Qing, Gu

    2016-06-01

    Based on a first-principles approach, we establish an alternating-current (AC) relaxation theory for a rotating metallic particle with complex dielectric constant . Here is the real part, the conductivity, ω 0 the angular frequency of an AC electric field, and . Our theory yields an accurate interparticle force, which is in good agreement with the existing experiment. The agreement helps to show that the relaxations of two kinds of charges, namely, surface polarized charges (described by ) and free charges (corresponding to ), contribute to the unusually large reduction in the attracting interparticle force. This theory can be adopted to determine the relaxation time of dynamic particles in various fields. Project supported by the National Natural Science Foundation of China (Grant No. 11222544), the Fok Ying Tung Education Foundation (Grant No. 131008), the Program for New Century Excellent Talents in University, China (Grant No. NCET-12-0121), and the National Key Basic Research Program of China (Grant No. 2011CB922004).

  5. The double-temperature ratchet model and current reversal of coupled Brownian motors

    CERN Document Server

    Li, Chen-pu; Zheng, Zhi-gang

    2016-01-01

    Based on the transport features and experimental phenomena observed in studies of molecular motors, we proposed the double-temperature ratchet model of coupled motors to reveal the dynamical mechanism of cooperative transport of motors with two heads, where the interactions and the asynchronous between two motor heads are taken into account. We investigated the collective unidirectional transport of coupled system, and find that the direction of motion can be inversed under certain conditions. Inverse motion can be achieved by modulating the coupling strength, the coupling free length and the asymmetric efficient of the periodic potential, which is understood in terms of the effective-potential theory. The dependence of directed current on various parameters is studied systematically. Directed transport of coupled Brownian motors can be manipulated and optimized by adjusting pulsating period or the phase shift of the pulsating temperature.

  6. Enhanced motor learning following task-concurrent dual transcranial direct current stimulation.

    Directory of Open Access Journals (Sweden)

    Sophia Karok

    Full Text Available OBJECTIVE: Transcranial direct current stimulation (tDCS of the primary motor cortex (M1 has beneficial effects on motor performance and motor learning in healthy subjects and is emerging as a promising tool for motor neurorehabilitation. Applying tDCS concurrently with a motor task has recently been found to be more effective than applying stimulation before the motor task. This study extends this finding to examine whether such task-concurrent stimulation further enhances motor learning on a dual M1 montage. METHOD: Twenty healthy, right-handed subjects received anodal tDCS to the right M1, dual tDCS (anodal current over right M1 and cathodal over left M1 and sham tDCS in a repeated-measures design. Stimulation was applied for 10 mins at 1.5 mA during an explicit motor learning task. Response times (RT and accuracy were measured at baseline, during, directly after and 15 mins after stimulation. Motor cortical excitability was recorded from both hemispheres before and after stimulation using single-pulse transcranial magnetic stimulation. RESULTS: Task-concurrent stimulation with a dual M1 montage significantly reduced RTs by 23% as early as with the onset of stimulation (p<0.01 with this effect increasing to 30% at the final measurement. Polarity-specific changes in cortical excitability were observed with MEPs significantly reduced by 12% in the left M1 and increased by 69% in the right M1. CONCLUSION: Performance improvement occurred earliest in the dual M1 condition with a stable and lasting effect. Unilateral anodal stimulation resulted only in trendwise improvement when compared to sham. Therefore, task-concurrent dual M1 stimulation is most suited for obtaining the desired neuromodulatory effects of tDCS in explicit motor learning.

  7. Mountain Plains Learning Experience Guide: Electric Motor Repair.

    Science.gov (United States)

    Ziller, T.

    This Electric Motor Repair Course is designed to provide the student with practical information for winding, repairing, and troubleshooting alternating current and direct current motors, and controllers. The course is comprised of eight units: (1) Electric Motor Fundamentals, (2) Rewinding, (3) Split-phase Induction Motors, (4) Capacitor Motors,…

  8. Impairments of motor-cortex responses to unilateral and bilateral direct current stimulation in schizophrenia

    Directory of Open Access Journals (Sweden)

    Alkomiet eHasan

    2013-10-01

    Full Text Available Transcranial direct current stimulation (tDCS is a non-invasive stimulation technique that can be applied to modulate cortical activity through induction of cortical plasticity. Since various neuropsychiatric disorders are characterised by fluctuations in cortical activity levels (e.g. schizophrenia, tDCS is increasingly investigated as a treatment tool. Several studies have shown that the induction of cortical plasticity following classical, unilateral tDCS is reduced or impaired in the stimulated and non-stimulated primary motor cortices (M1 of schizophrenia patients. Moreover, an alternative, bilateral tDCS setup has recently been shown to modulate cortical plasticity in both hemispheres in healthy subjects, highlighting another potential treatment approach. Here we present the first study comparing the efficacy of unilateral tDCS (cathode left M1, anode right supraorbital with simultaneous bilateral tDCS (cathode left M1, anode right M1 in schizophrenia patients. tDCS-induced cortical plasticity was monitored by investigating motor-evoked potentials induced by single-pulse transcranial magnetic stimulation applied to both hemispheres. Healthy subjects showed a reduction of left M1 excitability following unilateral tDCS on the stimulated left hemisphere and an increase in right M1 excitability following bilateral tDCS. In schizophrenia, no plasticity was induced following both stimulation paradigms. The pattern of these results indicates a complex interplay between plasticity and connectivity that is impaired in schizophrenia patients. Further studies are needed to clarify the biological underpinnings and clinical impact of these findings.

  9. Transient motor current signature analysis via modulus of the continuous complex wavelet: A pattern approach

    International Nuclear Information System (INIS)

    Highlights: • Transient MCSA detects motor faults via time–frequency analysis of the current. • The modulus of the CCWT shows the current harmonics in the time–frequency plane. • The choice of the DOG as mother wavelet is made after a comparative analysis. • Each motor fault harmonics displays a different pattern in the generated image. • A commercial motor with a rotor broken bar has been used to present the method. - Abstract: In this paper a new method to perform Transient Motor Current Signature analysis (TMCSA), based on the Continuous Complex Wavelet Transform (CCWT) of the line current, is presented. TMCSA is a powerful online method for diagnosing motor faults. Unlike traditional MCSA methods, based on the Fourier Transform (FT) of the stator currents in stationary regime, it can identify not only the presence of current harmonics that are characteristic of each motor fault, but also their unique time–frequency evolution pattern. This feature greatly increases its reliability, helping to discard non-fault related harmonics like those generated by periodic loads or voltage unbalances. In the case of a machine with broken bars, the representation in the time–frequency plane of the left sideband harmonic during the startup transient (LSHst) constitutes such a clear fault pattern. Mathematical tools that are able to characterize non-stationary signals are needed in TMCSA, such as the CCWT. It is a highly redundant transformation of the current signal into the time–frequency domain, and its modulus is used in this paper to generate a high resolution graphic pattern of the fault. Experimental results obtained on a 1.1 kW three-phase squirrel-cage induction motor with broken bars are discussed

  10. Inter-individual variability in optimal current direction for transcranial magnetic stimulation of the motor cortex

    DEFF Research Database (Denmark)

    Balslev, Daniela; Braet, Wouter; McAllister, Craig;

    2007-01-01

    We evaluated inter-individual variability in optimal current direction for biphasic transcranial magnetic stimulation (TMS) of the motor cortex. Motor threshold for first dorsal interosseus was detected visually at eight coil orientations in 45 degrees increments. Each participant (n=13) completed...... two experimental sessions. One participant with low test-retest correlation (Pearson's rmotor threshold was compared to EMG detection; motor thresholds were very similar and highly correlated (0.94-0.99). Similar with previous studies...... sample the optimal orientation of current direction was normally distributed around the postero-lateral orientation with a range of 63 degrees (S.D.=13.70 degrees). Whenever the intensity of stimulation at the target site is calculated as a percentage from the motor threshold, in order to minimize...

  11. SIMULATION AND IMPLEMENTATION OF CURRENT CONTROL OF BRUSHLESS DC MOTOR BASED ON A COMMON DC SIGNAL

    Directory of Open Access Journals (Sweden)

    J.Karthikeyan

    2010-06-01

    Full Text Available The objective of this project is to build a simple current controlled modulation technique for brushless dc motors. In electric traction and most other applications, a wide range of speed and torque control of the electric motor is required. The dc machine fulfills these requirements, but the dc machine requires constant maintenance. But the brushless permanent magnet motors do not have brushes and so they require less maintenance only. Brushless dc motors are widely used in applications which require wide range of speed and torque control because of its low inertia, fast response, high reliability and maintenance free. This current controlled technique is based on the generation of quasi- square wave currents using only one controller for the three phases. The current control strategy uses a triangular carrier for the power transistors which is simpler and more accuratethan any other options. The advantages of this technique are: a The stator currents are completely characterized by their maximum amplitude , b The three phases are controlled with the same dc component , and then the phase currents are kept at exactly the same magnitude I max, c The dc link current measurement is not required .d phase currents are kept balanced and phase over currents are eliminated.

  12. Analytical Method of Malculation of the Current and Torque a Reluctance Stepper Motor via Fourier Series

    Directory of Open Access Journals (Sweden)

    Maria Zaskalicka

    2008-01-01

    Full Text Available Reluctance stepper motors are becoming to be very attractive transducer to conversion of electric signal to the mechanical position. Due to its simple construction is reluctance machine considered a very reliable machine which not requiring any maintenance. Present paper proposes a mathematical method of an analytical calculus of a phase current and electromagnetic torque of the motor via Fourier series. Saturation effect and winding reluctance are neglected.

  13. Effects of alternating current stimulation on the healthy and diseased brain

    Directory of Open Access Journals (Sweden)

    Aini Ismafairus eAbd Hamid

    2015-10-01

    Full Text Available Cognitive and neurological dysfunctions can severely impact a patient’s daily activities. In addition to medical treatment, non-invasive transcranial alternating current stimulation (tACS has been proposed as a therapeutic technique to improve the functional state of the brain. Although during the last years tACS was applied in numerous studies to improve motor, somatosensory, visual and higher order cognitive functions, our knowledge is still limited regarding the mechanisms as to which type of ACS can affect cortical functions and altered neuronal oscillations seem to be the key mechanism. Because alternating current send pulses to the brain at predetermined frequencies, the online- and after-effects of ACS strongly depend on the stimulation parameters so that ‘optimal’ ACS paradigms could be achieved. This is of interest not only for neuroscience research but also for clinical practice. In this study, we summarize recent findings on ACS-effects under both normal conditions and in brain diseases.

  14. Investigation of Si(001) stable surfaces in alternating current heating

    Science.gov (United States)

    Doi, T.; Koguchi, M.

    2016-11-01

    The topography of a Si(001) vicinal surface is investigated using reflection electron microscopy (REM) during alternating current (AC) heating of the surface in ultra-high vacuum. The normal direction of the surface is slightly tilted from the [001] direction at θx or θy on the x or y axis (they are orthogonal directions in the Si(001) surface), and the average widths of the terraces (a or b in x or y axis) are determined by θx or θy; the direction perpendicular to the incidence electron beam on the surface is selected as the x (horizontal) axis in each REM image. Alternating current heating changes each initial surface from stable to double-domain (DD), in which 2 × 1 and 1 × 2 terraces are arranged regularly with approximately equal width, at its transition temperature Tc; the dimer rows are parallel to the x or y axis in the 1 × 2 or 2 × 1 terraces. There are two types of stable surfaces in the vicinal surface. At temperatures below its Tc, the surface with horizontally (vertically) long terraces, where b a), changes to a 2 × 1 (1 × 2) surface with wide 2 × 1 (1 × 2) and narrow 1 × 2 (2 × 1) terraces. The terrace, the short side of which is parallel to its dimer row direction, grows to create a stable surface by thermal diffusion of Si atoms at temperatures below Tc. During AC heating, thermal diffusion plays a key role in analyzing the kinetics of the atoms on the surface because the thermal effect acts as the driving force for the atoms that have not yet evaporated from the surface. Then, by evaporating atoms from the vicinal surface, AC heating creates a DD surface at temperatures between its Tc and 1100 °C and a rugged surface consisting of small 2 × 1 and 1 × 2 terraces at temperatures above 1100 °C.

  15. Accelerated test methods for life prediction of hermetic motor insulation systems exposed to alternative refrigerant/lubricant mixtures

    Science.gov (United States)

    Ellis, P. F., II; Ferguson, A. F.

    1995-04-01

    In 1992, the Air-Conditioning and Refrigeration Technology Institute, Inc. (ARTI) contracted Radian Corporation to ascertain whether an improved accelerated test method or procedure could be developed that would allow prediction of the life of motor insulation materials used in hermetic motors for air-conditioning and refrigeration equipment operated with alternative refrigerant/lubricant mixtures. Phase 1 of the project, Conceptual Design of an accelerated test method and apparatus, was successfully completed in June 1993. The culmination of that effort was the concept of the Simulated Stator Unit (SSU) test. The objective of the Phase 2 limited proof-of-concept demonstration was to: answer specific engineering/design questions; design and construct an analog control sequencer and supporting apparatus; and conduct limited tests to determine the viability of the SSU test concept. This report reviews the SSU test concept, and describes the results through the conclusion of the proof-of-concept prototype tests in March 1995. The technical design issues inherent in transforming any conceptual design to working equipment have been resolved, and two test systems and controllers have been constructed. Pilot tests and three prototype tests have been completed, concluding the current phase of work. One prototype unit was tested without thermal stress loads. Twice daily insulation property measurements (IPM's) on this unit demonstrated that the insulation property measurements themselves did not degrade the SSU.

  16. Ground Return Current Behaviour in High Voltage Alternating Current Insulated Cables

    Directory of Open Access Journals (Sweden)

    Roberto Benato

    2014-12-01

    Full Text Available The knowledge of ground return current in fault occurrence plays a key role in the dimensioning of the earthing grid of substations and of cable sealing end compounds, in the computation of rise of earth potential at substation sites and in electromagnetic interference (EMI on neighbouring parallel metallic conductors (pipes, handrails, etc.. Moreover, the ground return current evaluation is also important in steady-state regime since this stray current can be responsible for EMI and also for alternating current (AC corrosion. In fault situations and under some assumptions, the ground return current value at a substation site can be computed by means of k-factors. The paper shows that these simplified and approximated approaches have a lot of limitations and only multiconductor analysis can show the ground return current behaviour along the cable (not only the two end values both in steady-state regime and in short circuit occurrence (e.g., phase-to-ground and phase-to-phase-to-ground. Multiconductor cell analysis (MCA considers the cable system in its real asymmetry without simplified and approximated hypotheses. The sensitivity of ground return current on circuit parameters (cross-bonding box resistances, substation earthing resistances, soil resistivity is presented in the paper.

  17. The effect of 10 Hz transcranial alternating current stimulation (tACS on corticomuscular coherence

    Directory of Open Access Journals (Sweden)

    Claudia eWach

    2013-08-01

    Full Text Available Synchronous oscillatory activity at alpha (8-12 Hz, beta (13-30 Hz, and gamma (30-90 Hz fre-quencies is assumed to play a key role for motor control. Corticomuscular coherence (CMC represents an established measure of the pyramidal system’s integrity. Transcranial alternating current stimulation (tACS offers the possibility to modulate ongoing oscillatory activity. Behaviourally, 20 Hz tACS in healthy subjects has been shown to result in movement slowing. However, the neurophysiological changes underlying these effects are not entirely understood yet. The present study aimed at ascertaining the effects of tACS at 10 and 20 Hz in healthy subjects on CMC and local power of the primary sensorimotor cortex. Neuromagnetic activity was recorded during isometric contraction before and at two time points (2-10 min and 30-38 min after tACS of the left primary motor cortex (M1, using a 306 channel whole head magnetoencephalo-graphy (MEG system. Additionally, electromyography (EMG of the right extensor digitorum communis (EDC muscle was measured. TACS was applied at 10 and 20 Hz, respectively, for 10 min at 1 mA. Sham stimulation served as control condition. The data suggest that 10 Hz tACS significantly reduced low gamma band CMC during isometric contraction. This implies that tACS does not necessarily cause effects at stimulation frequency. Rather, the findings suggest cross-frequency interplay between alpha and low gamma band activity modulating functional interaction between motor cortex and muscle.

  18. Characteristics of alternating current hopping conductivity in DNA sequences

    Institute of Scientific and Technical Information of China (English)

    Ma Song-Shan; Xu Hui; Wang Huan-You; Guo Rui

    2009-01-01

    This paper presents a model to describe alternating current (AC) conductivity of DNA sequences,in which DNA is considered as a one-dimensional (1D) disordered system,and electrons transport via hopping between localized states.It finds that AC conductivity in DNA sequences increases as the frequency of the external electric field rises,and it takes the form of σac(ω)~ω2 ln2(1/ω).Also AC conductivity of DNA sequences increases with the increase of temperature,this phenomenon presents characteristics of weak temperature-dependence.Meanwhile,the AC conductivity in an off diagonally correlated case is much larger than that in the uncorrelated case of the Anderson limit in low temperatures,which indicates that the off-diagonal correlations in DNA sequences have a great effect on the AC conductivity,while at high temperature the off-diagonal correlations no longer play a vital role in electric transport. In addition,the proportion of nucleotide pairs p also plays an important role in AC electron transport of DNA sequences.For p<0.5,the conductivity of DNA sequence decreases with the increase of p,while for p > 0.5,the conductivity increases with the increase of p.

  19. Inflammatory bowel diseases: an update of current treatment alternatives.

    Directory of Open Access Journals (Sweden)

    Lucrecia Suárez

    2009-11-01

    Full Text Available Inflammatory bowel diseases (IBD are characterized for having an unpredictable clinical course with periods of inactivity alternating with relapses, a very variable response to treatment and the constant threat of diverse complications. Management of IBD in children may be of particular complexity, added to the fact that published clinical trials are limited, and scientific evidence seems contradictory, explain in part why to current date there is no international consensus regarding treatment in this age group. A suitable therapy should aim at inducing and maintaining remission for as long as possible, encourage adequate growth and preventing potential complications from appearing. In more recent years, development of new therapeutic agents has allowed a more integrative approach which takes in consideration other aspects of the disease such as nutritional status, psychological welfare and general quality of life. One must also keep in mind that none of these therapeutic resources is exempt of side effects on short and long term basis, consequently, it is imperative to be thoughtful of individual features in order to make accurate clinical decisions and offer a tailored management plan which should be able to modify the disease evolution.

  20. Depolarization of a piezoelectric film under an alternating current field

    Science.gov (United States)

    Kwok, K. W.; Cheung, M. K.; Chan, H. L. W.; Choy, C. L.

    2007-03-01

    In this article, we demonstrate that a sol-gel-derived niobium-doped lead zirconate titanate film can be depolarized by the application of alternating current (ac) fields of diminishing amplitude and we explain the phenomenon based on the concept of the Preisach model. The amplitude of the ac fields is decreased from 20 to 2 MV/m in ten steps. The observed piezoelectric coefficient of the film decreases after each ac field step. Depending on the initial polarization and the direction of the ac fields, the piezoelectric coefficient can decrease to a very small value indicating the complete depolarization of the film. Our results reveal the existence of a distribution of the switching fields in the microdomains (Preisach dipolar units), and that because of mutual interactions the magnitudes of the switch-up and switch-down fields for each microdomain are not necessarily the same. Our results also suggest that the sputter deposition of the top electrode can induce more "down-state" microdomains, thus giving rise to an initial polarization in the film. Because of interactions with other microdomains or other effects, part of these microdomains exhibit very high switching fields.

  1. Electrical Motor Current Signal Analysis using a Dynamic Time Warping Method for Fault Diagnosis

    International Nuclear Information System (INIS)

    This paper presents the analysis of phase current signals to identify and quantify common faults from an electrical motor based on dynamic time warping (DTW) algorithm. In condition monitoring, measurements are often taken when the motor undertakes varying loads and speeds. The signals acquired in these conditions show similar profiles but have phase shifts, which do not line up in the time-axis for adequate comparison to discriminate the small changes in machine health conditions. In this study, DTW algorithms are exploited to align the signals to an ideal current signal constructed based on average operating conditions. In this way, comparisons between the signals can be made directly in the time domain to obtain residual signals. These residual signals are then based on to extract features for detecting and diagnosing the faults of the motor and components operating under different loads and speeds. This study provides a novel approach to the analysis of electrical current signal for diagnosis of motor faults. Experimental data sets of electrical motor current signals have been studied using DTW algorithms. Results show that DTW based residual signals highlights more the modulations due to the compressor process. And hence can obtain better fault detection and diagnosis results.

  2. Bearingless motor's radial suspension force control based on flux equivalent with virtual winding current analysis method

    Institute of Scientific and Technical Information of China (English)

    ZHU HuangQiu; CHENG OiuLiang

    2009-01-01

    A bearingless motor has two sets of intercoupling stator windings, namely torque windings and sus-pension force windings. The decoupling control of the two sets is difficult and a key technology to stable operation for a bearingless motor. In this paper, a simple, reliable and accurate analysis method is put forward using the concept of flux equivalent with virtual winding currents. By this method, the suspension operation condition PB=PM±1 for bearingless motors is testified, and under the rotation condition of the motor, it is also proved that currents in suspension force windings must have the same phase sequence and frequency as torque windings to generate a stable single direction radial force in the rotor's whole circumference. On this basis, the control strategy of realizing the suspension opera-tion of the bearingless motor is presented, and a prototype of the bearingless surface-mounted per-manent magnet synchronous motor is tested. The research results have indicated that the experimen-tal results correspond with theoretical analysis adopting this method, a stable and reliable radial sus-pension force can be generated, and the validity and feasibility of this control strategy are confirmed.

  3. Transcranial direct current stimulation over the supplementary motor area modulates the preparatory activation level in the human motor system

    Science.gov (United States)

    Carlsen, Anthony N.; Eagles, Jeremy S.; MacKinnon, Colum D.

    2016-01-01

    Transcranial direct current stimulation (tDCS) is a non-invasive stimulation method that can induce transient polarity-specific neuroplastic changes in cortical excitability lasting up to 1 h post-stimulation. While excitability changes with stimulation over the primary motor cortex have been well documented, the functional effects of stimulation over premotor regions are less well understood. In the present experiment, we tested how cathodal and anodal tDCS applied over the region of the supplementary motor area (SMA) affected preparation and initiation of a voluntary movement. Participants performed a simple reaction time (RT) task requiring a targeted wrist-extension in response to a go-signal. In 20% of RT trials a startling acoustic stimulus (SAS) was presented 500 ms prior to the “go” signal in order to probe the state of motor preparation. Following the application of cathodal, anodal, or sham tDCS (separate days) over SMA for 10 min, participants performed blocks of RT trials at 10 min intervals. While sham stimulation did not affect RT or incidence of early release by the SAS, cathodal tDCS led to a significant slowing of RT that peaked 10 min after the end of stimulation and was associated with a marked decrease in the incidence of movement release by the SAS. In contrast, anodal tDCS resulted in faster RTs, but the incidence of release was unchanged. These results are consistent with the SMA playing a role in the pre-planning of movements and that modulating its activity with tDCS can lead to polarity-specific changes in motor behavior. PMID:25446764

  4. Alternate propellants for the space shuttle solid rocket booster motors. [for reducing environmental impact of launches

    Science.gov (United States)

    1973-01-01

    As part of the Shuttle Exhaust Effects Panel (SEEP) program for fiscal year 1973, a limited study was performed to determine the feasibility of minimizing the environmental impact associated with the operation of the solid rocket booster motors (SRBMs) in projected space shuttle launches. Eleven hypothetical and two existing limited-experience propellants were evaluated as possible alternates to a well-proven state-of-the-art reference propellant with respect to reducing emissions of primary concern: namely, hydrogen chloride (HCl) and aluminum oxide (Al2O3). The study showed that it would be possible to develop a new propellant to effect a considerable reduction of HCl or Al2O3 emissions. At the one extreme, a 23% reduction of HCl is possible along with a ll% reduction in Al2O3, whereas, at the other extreme, a 75% reduction of Al2O3 is possible, but with a resultant 5% increase in HCl.

  5. PROTECTION OF HOUSEHOLD APPLIANCES INDUCTION MOTORS AGAINST OVERCURRENT TAKING INTO ACCOUNT NONLINEAR DISTORTION OF PHASE CURRENT

    Directory of Open Access Journals (Sweden)

    A.G. Sereda

    2015-06-01

    Full Text Available Purpose. Theoretical justification and engineering of induction motors heat protection method from overload currents taking into account nonlinear distortion of the phase current and implementation as a microprocessor device functioning algorithm. Methodology. To solve the problem used the theory of the representing complex harmonic oscillations analog signals expansion into the oscillation spectrum forming elementary harmonic components in order to compare their properties by applying the theory of discrete signals and systems, as well as methods of spectral analysis and discrete signals filtering. The harmonic analysis versatility is that any periodic signal may be synthesized from harmonic oscillation of certain amplitude, frequency and initial phase. A mathematical model for determining the phase current harmonic content of power supply networks with isolated neutral and non-linear loads types and, as a consequence, the distortion of sinusoidal phase current change is developed by multiplying the analog current in time dependency on the grate delta-function with different sampling intervals, in which the use of simple and widely used in relay protection units, in particular electronic overcurrent relays, mathematical operations of integration squares instantaneous current allows the most in harmony with the mathematical tools to build other network protection types. Findings. The necessity to increase the sensitivity of the induction motors heat protection from overload currents taking into account nonlinear distortion of the phase currents is proved. By nonlinear distortion harmonic analysis of the phase currents the motor protection reliability increasing provided by taking into account the higher harmonic components of the phase currents, which causes to additional losses and heating of the stator winding. It uses the simplest and widely used in protective relaying mathematical apparatus determining of most significant higher harmonics

  6. Bearing fault detection using motor current signal analysis based on wavelet packet decomposition and Hilbert envelope

    Directory of Open Access Journals (Sweden)

    Imaouchen Yacine

    2015-01-01

    Full Text Available To detect rolling element bearing defects, many researches have been focused on Motor Current Signal Analysis (MCSA using spectral analysis and wavelet transform. This paper presents a new approach for rolling element bearings diagnosis without slip estimation, based on the wavelet packet decomposition (WPD and the Hilbert transform. Specifically, the Hilbert transform first extracts the envelope of the motor current signal, which contains bearings fault-related frequency information. Subsequently, the envelope signal is adaptively decomposed into a number of frequency bands by the WPD algorithm. Two criteria based on the energy and correlation analyses have been investigated to automate the frequency band selection. Experimental studies have confirmed that the proposed approach is effective in diagnosing rolling element bearing faults for improved induction motor condition monitoring and damage assessment.

  7. Detection of outer raceway bearing defects in small induction motors using stator current analysis

    Indian Academy of Sciences (India)

    İzzet Y Önel; K Burak Dalci; İbrahim Senol

    2005-12-01

    We investigate the application of induction motor stator current spectral analysis (MCSA) for detection of rolling element bearing damage from the outer raceway. In this work, MCSA and vibration analysis are applied to induction motor to detect outer raceway defects in faulty bearings. Data acquisition, recording,and fast fourier transform (FFT) algorithms are done by using the LabVIEW programming language. Experimental results verify the relationship between vibration analysis and MCSA, and identify the presence of outer raceway bearing defects in induction machines. This work also indicates that detecting fault frequencies by motor currents is more difficult than detecting them by vibration analysis. The use of intensive resolution FFT is recommended in MCSA for detecting faults easily. Reinstalling a faulty bearing can alter the characteristic frequencies and it is difficult to compare results from different bearings or even from the same bearing in different installations.

  8. COMPARISON PERFORMANCE OF INDUCTION MOTOR USING SVPWM AND HYSTERESIS CURRENT CONTROLLER

    Directory of Open Access Journals (Sweden)

    FIZATUL AINI PATAKOR

    2011-08-01

    Full Text Available This paper presents the comparative performances of three phase induction motors using space vector pulse width modulation (SVPWM and hysteresis current controller. An indirect field orientation is applied to ensure decoupling control between torque and flux of the induction motor. The hysteresis current controller is built in with PI speed controller and three hysteresis current bands while the SVPWM system is embedded with the two control loops, the inner current control loop and the outer speed control loop using PI controller. Both systems were run and tested using MATLAB/SIMULINK software. The simulation results demonstrate that the SVPWM can improve the quality of the stator current and reduce the torque ripple while maintaining the other performance characteristics of the system.

  9. Simplified Modeling, Analysis and Simulation of Permanent Magnet Brushless Direct Current Motors for Sensorless Operation

    Directory of Open Access Journals (Sweden)

    E. Kaliappan

    2012-01-01

    Full Text Available Problem statement: In this study, a simplified modeling and experimental analysis of Permanent Magnet Brushless DC (PMBLDC motors for Sensorless operation using MATLAB/SIMULINK. This model provides a mechanism for monitoring and controlling the voltage, current, speed and torque response. Approach: BLDC motor is modeled as sub-blocks. The inverter and switching function are implemented as S-function builder block. The Sensorless scheme employs direct back emf based zero crossing detection technique. Results: The proposed model with Sensorless control technique with back emf zero crossing detection is tested in the BLDC Motor and the performance was evaluated. The simulated and experimental results show that the proposed modeling works quite well during starting and running conditions. Conclusion/Recommendation: The developed model consists of several independent sub-blocks, that can be used in the modeling of Permanent Magnet Sinusoidal Motor and induction motor. Hence the developed simulation model is a design tool to study the dynamic behavior of Sensorless Controlled Brushless DC Motor.

  10. Electrical motor current signal analysis using a modified bispectrum for fault diagnosis of downstream mechanical equipment

    Science.gov (United States)

    Gu, F.; Shao, Y.; Hu, N.; Naid, A.; Ball, A. D.

    2011-01-01

    This paper presents the use of the induction motor current to identify and quantify common faults within a two-stage reciprocating compressor based on bispectrum analysis. The theoretical basis is developed to understand the nonlinear characteristics of current signals when the motor undertakes a varying load under different faulty conditions. Although conventional bispectrum representation of current signal allows the inclusion of phase information and the elimination of Gaussian noise, it produces unstable results due to random phase variation of the sideband components in the current signal. A modified bispectrum based on the amplitude modulation feature of the current signal is then adopted to combine both lower sidebands and higher sidebands simultaneously and hence characterise the current signal more accurately. Based on this new bispectrum analysis a more effective diagnostic feature, namely normalised bispectral peak, is developed for fault classification. In association with the kurtosis value of the raw current signal, the bispectrum feature gives rise to reliable fault classification results. In particular, the low feature values can differentiate the belt looseness from the other fault cases and different degrees of discharge valve leakage and inter-cooler leakage can be separated easily using two linear classifiers. This work provides a novel approach to the analysis of stator current for the diagnosis of motor drive faults from downstream driving equipment.

  11. Permanent Magnet Eddy Current Loss Analysis of a Novel Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Zhang, Yuqiu; Lu, Kaiyuan; Ye, Yunyue

    2012-01-01

    In this paper, a new motor integrated permanent magnet gear (MIPMG) is discussed. The focus is on eddy current loss analysis associated to permanent magnets (PMs). A convenient model of MIPMG is provided based on 2-D field-motion coupled time-stepping finite element method for transient eddy...... current analysis. The model takes the eddy current effect of PMs into account in determination of the magnetic field in the air-gap and in the magnet regions. The eddy current losses generated in the magnets are properly interpreted. Design improvements for reducing the eddy current losses are suggested...

  12. Transcranial direct current stimulation of the primary motor cortex improves word-retrieval in older adults.

    Directory of Open Access Journals (Sweden)

    Marcus eMeinzer

    2014-09-01

    Full Text Available Language facilitation by transcranial direct current stimulation (tDCS in healthy individuals has generated hope that tDCS may also allow improving language impairment after stroke (aphasia. However, current stimulation protocols have yielded variable results and may require identification of residual language cortex using functional magnetic resonance imaging (fMRI, which complicates incorporation into clinical practice. Based on previous behavioral studies that demonstrated improved language processing by motor system pre-activation, the present study assessed whether tDCS administered to the primary motor cortex (M1 can enhance language functions.This proof-of-concept study employed a sham-tDCS controlled, cross-over, within-subject design and assessed the impact of unilateral excitatory (anodal and bihemispheric (dual tDCS in eighteen healthy older adults during semantic word-retrieval and motor speech tasks. Simultaneous fMRI scrutinized the neural mechanisms underlying tDCS effects.Both active tDCS conditions significantly improved word-retrieval compared to sham-tDCS. The direct comparison of activity elicited by word-retrieval vs. motor-speech trials revealed bilateral frontal activity increases during both anodal- and dual-tDCS compared to sham-tDCS. This effect was driven by more pronounced deactivation of frontal regions during the motor-speech task, while activity during word-retrieval trials was unaffected by the stimulation. No effects were found in M1 and secondary motor regions.Our results show that tDCS administered to M1 can improve word-retrieval in healthy individuals, thereby providing a rationale to explore whether M1-tDCS may offer a novel approach to improve language functions in aphasia. fMRI revealed neural facilitation specifically during motor speech trials, which may have reduced switching costs between the overlapping neural systems for lexical retrieval and speech processing, thereby resulting in improved

  13. Phase-compensation-based dynamic time warping for fault diagnosis using the motor current signal

    Science.gov (United States)

    Zhen, D.; Zhao, H. L.; Gu, F.; Ball, A. D.

    2012-05-01

    Dynamic time warping (DTW) is a time-domain-based method and widely used in various similar recognition and data mining applications. This paper presents a phase-compensation-based DTW to process the motor current signals for detecting and quantifying various faults in a two-stage reciprocating compressor under different operating conditions. DTW is an effective method to align two signals for dissimilarity analysis. However, it has drawbacks such as singularities and high computational demands that limit its application in processing motor current signals for obtaining modulation characteristics accurately in diagnosing compressor faults. Therefore, a phase compensation approach is developed to reduce the singularity effect and a sliding window is designed to improve computing efficiency. Based on the proposed method, the motor current signals measured from the compressor induced with different common faults are analysed for fault diagnosis. Results show that residual signal analysis using the phase-compensation-based DTW allows the fault-related sideband features to be resolved more accurately for obtaining reliable fault detection and diagnosis. It provides an effective and easy approach to the analysis of motor current signals for better diagnosis in the time domain in comparison with conventional Fourier-transform-based methods.

  14. Experimental Investigations on PV Powered SVM-DTC Induction Motor without AC Phase Current Sensors

    Directory of Open Access Journals (Sweden)

    T. Muthamizhan

    2014-05-01

    Full Text Available The paper presents a low-cost, phase-current reconstruction algorithm for space vector modulated direct torque controlled induction motor using the information obtained from only one shunt resistor which is in series with low side switches in a conventional three-phase inverter. The aim is to develop a low-cost high - performance induction motor drive. It uses the dc-link voltage and dc current to reconstruct the stator currents needed to estimate the motor flux and the electromagnetic torque. Photovoltaic arrays convert solar power to dc electric power; uses chopper and dc-ac inverter to fed three phase Induction Motor. The chopper used here is current fed full bridge boost dc-dc converter, which is preferred and extensively used in high voltage applications and advantageous over voltage fed converters. The inverter switches are controlled by PWM techniques obtained from SVM-DTC of IM. The experimental investigations are given to prove the ability of the proposed scheme of reproducing the performances of a SVM- DTC IM drive.

  15. Phase-compensation-based dynamic time warping for fault diagnosis using the motor current signal

    International Nuclear Information System (INIS)

    Dynamic time warping (DTW) is a time-domain-based method and widely used in various similar recognition and data mining applications. This paper presents a phase-compensation-based DTW to process the motor current signals for detecting and quantifying various faults in a two-stage reciprocating compressor under different operating conditions. DTW is an effective method to align two signals for dissimilarity analysis. However, it has drawbacks such as singularities and high computational demands that limit its application in processing motor current signals for obtaining modulation characteristics accurately in diagnosing compressor faults. Therefore, a phase compensation approach is developed to reduce the singularity effect and a sliding window is designed to improve computing efficiency. Based on the proposed method, the motor current signals measured from the compressor induced with different common faults are analysed for fault diagnosis. Results show that residual signal analysis using the phase-compensation-based DTW allows the fault-related sideband features to be resolved more accurately for obtaining reliable fault detection and diagnosis. It provides an effective and easy approach to the analysis of motor current signals for better diagnosis in the time domain in comparison with conventional Fourier-transform-based methods. (paper)

  16. Current Status of Helium-3 Alternative Technologies for Nuclear Safeguards

    Energy Technology Data Exchange (ETDEWEB)

    Henzlova, Daniela [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kouzes, R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McElroy, R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peerani, P. [European Commission, Ispra (Italy). Joint Research Centre; Aspinall, M. [Hybrid Instruments Ltd., Birmingham (United Kingdom); Baird, K. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Bakel, A. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Borella, M. [SCK.CEN, Mol (Belgium); Bourne, M. [Univ. of Michigan, Ann Arbor, MI (United States); Bourva, L. [Canberra Ltd., Oxford (United Kingdom); Cave, F. [Hybrid Instruments Ltd., Birmingham (United Kingdom); Chandra, R. [Arktis Radiation Detectors Ltd., Zurich (Sweden); Chernikova, D. [Chalmers Univ. of Technology (Sweden); Croft, S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dermody, G. [Symetrica Inc., Maynard, MA (United States); Dougan, A. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Ely, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fanchini, E. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Finocchiaro, P. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Gavron, Victor [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kureta, M. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Ianakiev, Kiril Dimitrov [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ishiyama, K. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Lee, T. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Martin, Ch. [Symetrica Inc., Maynard, MA (United States); McKinny, K. [GE Reuter-Stokes, Twinsburg, OH (United States); Menlove, Howard Olsen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Orton, Ch. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Pappalardo, A. [Istituto Nazionale di Fisica Nucleare (INFN), Milano (Italy); Pedersen, B. [European Commission, Ispra (Italy). Joint Research Centre; Peranteau, D. [National Nuclear Security Administration (NNSA), Washington, DC (United States); Plenteda, R. [Intl Atomic Energy Agency (IAEA), Vienna (Austria); Pozzi, S. [Univ. of Michigan, Ann Arbor, MI (United States); Schear, M. [Symetrica Inc., Maynard, MA (United States); Seya, M. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Siciliano, E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Stave, S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sun, L. [Proportional Technologies Inc., Houston, TX (United States); Swinhoe, Martyn Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tagziria, H. [European Commission, Ispra (Italy). Joint Research Centre; Vaccaro, S. [DG Energy (Luxembourg); Takamine, J. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Weber, A. -L. [Inst. for Radiological Protection and Nuclear Safety (IRSN), Fontenay-aux-Roses (France); Yamaguchi, T. [Japan Atomic Energy Agency (JAEA), Tokai (Japan); Zhu, H. [National Nuclear Security Administration (NNSA), Washington, DC (United States)

    2015-12-01

    International safeguards inspectorates (e.g., International Atomic Energy Agency {IAEA}, or Euratom) rely heavily on neutron assay techniques, and in particular, on coincidence counters for the verification of declared nuclear materials under safeguards and for monitoring purposes. While 3He was readily available, the reliability, safety, ease of use, gamma-ray insensitivity, and high intrinsic thermal neutron detection efficiency of 3He-based detectors obviated the need for alternative detector technologies. However, the recent decline of the 3He gas supply has triggered international efforts to develop and field neutron detectors that make use of alternative materials. In response to this global effort, the U.S. Department of Energy’s (DOE) National Nuclear Security Administration (NNSA) and Euratom launched a joint effort aimed at bringing together international experts, technology users and developers in the field of nuclear safeguards to discuss and evaluate the proposed 3He alternative materials and technologies. The effort involved a series of two workshops focused on detailed overviews and viability assessments of various 3He alternative technologies for use in nuclear safeguards applications. The key objective was to provide a platform for collaborative discussions and technical presentations organized in a compact, workshop-like format to stimulate interactions among the participants. The meetings culminated in a benchmark exercise providing a unique opportunity for the first inter-comparison of several available alternative technologies. This report provides an overview of the alternative technology efforts presented during the two workshops along with a summary of the benchmarking activities and results. The workshop recommendations and key consensus observations are discussed in the report, and used to outline a proposed path forward and future needs foreseeable in the area of 3He-alternative

  17. Compact ASD Topologies for Single-Phase Integrated Motor Drives with Sinusoidal Input Current

    DEFF Research Database (Denmark)

    Klumpner, Christian; Blaabjerg, Frede; Thoegersen, Paul

    2005-01-01

    needed to adjust the speed of the motor. The integrated motor drive concept is a result of merging the two units in order to achieve the following benefits [1-3]: reducing the design and the commissioning time in complex industrial equipments, no need for a cabinet to host the frequency converter......-density integration of the converter caused by the large size of the passive components (electrolytic capacitors and iron chokes) and vibration of the converter enclosure. This paper analyzes the implementation aspects for obtaining a compact and cost effective single-phase ASD with sinusoidal input current......, investigating the physical removal of power inductors from the converter enclosure in conjunction with reducing the number of semiconductor active devices. There are two ways to do that: to integrate the inductors in the unused area of the stator yoke of the motor or to use the leakage inductance...

  18. 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.

  19. Task-specific effect of transcranial direct current stimulation on motor learning

    Directory of Open Access Journals (Sweden)

    Cinthia Maria Saucedo Marquez

    2013-07-01

    Full Text Available Transcranial direct current stimulation (tDCS is a relatively new non-invasive brain stimulation technique that modulates neural processes. When applied to the human primary motor cortex (M1, tDCS has beneficial effects on motor skill learning and consolidation in healthy controls and in patients. However, it remains unclear whether tDCS improves motor learning in a general manner or whether these effects depend on which motor task is acquired. Here we compare whether the effect of tDCS differs when the same individual acquires (1 a Sequential Finger Tapping Task (SEQTAP and (2 a Visual Isometric Pinch Force Task (FORCE. Both tasks have been shown to be sensitive to tDCS applied over M1, however, the underlying processes mediating learning and memory formation might benefit differently from anodal-tDCS. Thirty healthy subjects were randomly assigned to an anodal-tDCS group or sham-group. Using a double-blind, sham-controlled cross-over design, tDCS was applied over M1 while subjects acquired each of the motor tasks over 3 consecutive days, with the order being randomized across subjects. We found that anodal-tDCS affected each task differently: The SEQTAP task benefited from anodal-tDCS during learning, whereas the FORCE task showed improvements only at retention. These findings suggest that anodal tDCS applied over M1 appears to have a task-dependent effect on learning and memory formation.

  20. Experiments with alternate currents of very high frequency

    CERN Document Server

    Tesla, Nikola

    2013-01-01

    Here is one of Nikola Tesla's most important lectures; it brightened the world and everything in it. Of all these phenomena the most important to study' are the current phenomena, on account of the already extensive and evergrowing use of currents for industrial purposes. It is now a century since the first practical source of current was produced, and, ever since, the phenomena which accompany the flow of currents have been diligently studied, and through the untiring efforts of scientific men the simple laws which govern them have been discovered.

  1. A comparison of alternating current and direct current electrospray ionization for mass spectrometry.

    Science.gov (United States)

    Sarver, Scott A; Chetwani, Nishant; Dovichi, Norman J; Go, David B; Gartner, Carlos A

    2014-04-01

    A series of studies comparing the performance of alternating current electrospray ionization (AC ESI) mass spectrometry (MS) and direct current electrospray ionization (DC ESI) MS have been conducted, exploring the absolute signal intensity and signal-to-background ratios produced by both methods using caffeine and a model peptide as targets. Because the high-voltage AC signal was more susceptible to generating gas discharges, the operating voltage range of AC ESI was significantly smaller than that for DC ESI, such that the absolute signal intensities produced by DC ESI at peak voltages were one to two orders of magnitude greater than those for AC ESI. Using an electronegative nebulizing gas, sulfur hexafluoride (SF6), instead of nitrogen (N2) increased the operating range of AC ESI by ~50%, but did not appreciably improve signal intensities. While DC ESI generated far greater signal intensities, both ionization methods produced comparable signal-to-background noise, with AC ESI spectra appearing qualitatively cleaner. A quantitative calibration analysis was performed for two analytes, caffeine and the peptide MRFA. AC ESI utilizing SF6 outperforms all other techniques for the detection of MRFA, producing chromatographic limits of detection nearly one order of magnitude lower than that of DC ESI utilizing N2, and one-half that of DC ESI utilizing SF6. However, DC ESI outperforms AC ESI for the analysis of caffeine, indicating that improvements in spectral quality may benefit certain compounds or classes of compounds, on an individual basis. PMID:24464359

  2. Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

    Energy Technology Data Exchange (ETDEWEB)

    Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

    1997-12-31

    Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

  3. Comparison of Unmodulated Current Control Characteristics of Permanent Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Anwar Muqorobin

    2014-12-01

    Full Text Available This paper discusses comparison of unmodulated current controls in PMSM, more specifically, on-off, sliding mode, predictive and hybrid controls. The purpose of this study is to select the most appropriate control technique to be adopted. The comparison method is preceded by modeling the motor and entering the values of the motor parameters. PI control is used for speed control and zero d-axis current is employed. Furthermore, performing simulation for each type ofthe selected current controls and analyzing their responses in terms of dq and abc currents, q-axis current response with step reference, as well as THD. Simulation results show that the on-off control gives the best overall performance based on its abc-axis current ripple and THD at large load torque. The hybrid control shows the best response occurring only at the fastest transient time of q-axis current but its response exhibits bad qualities compared with other controls. The predictive control yields the best responses offering the smallest d-axis ripple current and THD at small load torque condition. The sliding mode control, however, does not exhibit any prominent performance compared to the others. Results presented in this paper further indicate that for the PMSM used in the simulation the most appropriate control is the predictive control.

  4. Fault diagnosis of motor drives using stator current signal analysis based on dynamic time warping

    Science.gov (United States)

    Zhen, D.; Wang, T.; Gu, F.; Ball, A. D.

    2013-01-01

    Electrical motor stator current signals have been widely used to monitor the condition of induction machines and their downstream mechanical equipment. The key technique used for current signal analysis is based on Fourier transform (FT) to extract weak fault sideband components from signals predominated with supply frequency component and its higher order harmonics. However, the FT based method has limitations such as spectral leakage and aliasing, leading to significant errors in estimating the sideband components. Therefore, this paper presents the use of dynamic time warping (DTW) to process the motor current signals for detecting and quantifying common faults in a downstream two-stage reciprocating compressor. DTW is a time domain based method and its algorithm is simple and easy to be embedded into real-time devices. In this study DTW is used to suppress the supply frequency component and highlight the sideband components based on the introduction of a reference signal which has the same frequency component as that of the supply power. Moreover, a sliding window is designed to process the raw signal using DTW frame by frame for effective calculation. Based on the proposed method, the stator current signals measured from the compressor induced with different common faults and under different loads are analysed for fault diagnosis. Results show that DTW based on residual signal analysis through the introduction of a reference signal allows the supply components to be suppressed well so that the fault related sideband components are highlighted for obtaining accurate fault detection and diagnosis results. In particular, the root mean square (RMS) values of the residual signal can indicate the differences between the healthy case and different faults under varying discharge pressures. It provides an effective and easy approach to the analysis of motor current signals for better fault diagnosis of the downstream mechanical equipment of motor drives in the time

  5. Alternatives to animal testing: current status and future perspectives

    OpenAIRE

    Liebsch, Manfred; Grune, Barbara; Seiler, Andrea; Butzke, Daniel; Oelgeschläger, Michael; Pirow, Ralph; Adler, Sarah; Riebeling, Christian; Luch, Andreas

    2011-01-01

    On the occasion of the 20th anniversary of the Center for Alternative Methods to Animal Experiments (ZEBET), an international symposium was held at the German Federal Institute for Risk Assessment (BfR) in Berlin. At the same time, this symposium was meant to celebrate the 50th anniversary of the publication of the book “The Principles of Humane Experimental Technique” by Russell and Burch in 1959 in which the 3Rs principle (that is, Replacement, Reduction, and Refinement) has been coined and...

  6. Analysis of the dynamic response improvement of a turbocharged diesel engine driven alternating current generating set

    International Nuclear Information System (INIS)

    Reliability of electric supply systems is among the most required necessities of modern society. Turbocharged diesel engine driven alternating current generating sets are often used to prevent electric black outs and/or as prime electric energy suppliers. It is well known that turbocharged diesel engines suffer from an inadequate response to a sudden load increase, this being a consequence of the nature of the energy exchange between the engine and the turbocharger. The dynamic response of turbocharged diesel engines could be improved by electric assisting systems, either by direct energy supply with an integrated starter-generator-booster (ISG) mounted on the engine flywheel, or by an indirect energy supply with an electrically assisted turbocharger. An experimentally verified zero dimensional computer simulation method was used for the analysis of both types of electrical assistance. The paper offers an analysis of the interaction between a turbocharged diesel engine and different electric assisting systems, as well as the requirements for the supporting electric motors that could improve the dynamic response of a diesel engine while driving an AC generating set. When performance class compliance is a concern, it is evident that an integrated starter-generator-booster outperforms an electrically assisted turbocharger for the investigated generating set. However, the electric energy consumption and frequency recovery times are smaller when an electrically assisted turbocharger is applied

  7. Desempenho de um microtrator utilizando-se motores com diferentes alternativas energéticas = Performance of a microtractor using engines with different energetic alternatives

    Directory of Open Access Journals (Sweden)

    Denílson Eduardo Rodrigues

    2006-01-01

    Full Text Available Neste trabalho avaliou-se o desempenho de um microtrator equipado com três diferentes tipos de acionamento. Um mesmo chassi de um microtrator foi instalado, alternadamente, com um motor elétrico trifásico (MCA, um motor elétrico de corrente contínua (MCC e com um motor de combustão interna (MCI. Os ensaios do microtrator com cada um dos motores permitiram a determinação da força de tração máxima, da velocidade de deslocamento, do consumo de combustível e a patinagem dos rodados. O MCC desenvolveu maior força de tração, sendo 22% superior aos demais. O consumo específico de energia para os microtratores decresceu com o aumento da patinagem. This study evaluated the performance of a microtractor implemented in three different operational types. A microtractor chassis was alternately operated with a three-phase electric engine (MCA, a direct-current electric engine (MCC and an internal combustion engine (MCI. The rehearsals of the microtractor implemented in each one of the engines allowed determinations of the maximum tractive force, the forward speed and the fuel consumption in wheel skiddings. The MCC developed greater snatch force, being 22% superior to the others. The specific consumption on energy for the microtractors decreased as the skiddings increased.

  8. Extracting DC bus current information for optimal phase correction and current ripple in sensorless brushless DC motor drive

    Institute of Scientific and Technical Information of China (English)

    Zu-sheng HO; Chii-maw UANG; Ping-chieh WANG

    2014-01-01

    Brushless DC motor (BLDCM) sensorless driving technology is becoming increasingly established. However, op-timal phase correction still relies on complex calculations or algorithms. In finding the correct commutation point, the problem of phase lag is introduced. In this paper, we extract DC bus current information for auto-calibrating the phase shift to obtain the correct commutation point and optimize the control of BLDC sensorless driving. As we capture only DC bus current information, the original shunt resistor is used in the BLDCM driver and there is no need to add further current sensor components. Software processing using only simple arithmetic operations successfully accomplishes the phase correction. Experimental results show that the proposed method can operate accurately and stably at low or high speed, with light or heavy load, and is suitable for practical applications. This approach will not increase cost but will achieve the best performance/cost ratio and meet market expectations.

  9. Current sample size conventions: Flaws, harms, and alternatives

    Directory of Open Access Journals (Sweden)

    Bacchetti Peter

    2010-03-01

    Full Text Available Abstract Background The belief remains widespread that medical research studies must have statistical power of at least 80% in order to be scientifically sound, and peer reviewers often question whether power is high enough. Discussion This requirement and the methods for meeting it have severe flaws. Notably, the true nature of how sample size influences a study's projected scientific or practical value precludes any meaningful blanket designation of value of information methods, simple choices based on cost or feasibility that have recently been justified, sensitivity analyses that examine a meaningful array of possible findings, and following previous analogous studies. To promote more rational approaches, research training should cover the issues presented here, peer reviewers should be extremely careful before raising issues of "inadequate" sample size, and reports of completed studies should not discuss power. Summary Common conventions and expectations concerning sample size are deeply flawed, cause serious harm to the research process, and should be replaced by more rational alternatives.

  10. Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

    Directory of Open Access Journals (Sweden)

    Huangqiu Zhu

    2015-05-01

    Full Text Available Bearingless permanent magnet synchronous motors (BPMSMs, with all advantages of permanent magnet motors (PMSMs and magnetic bearings, have become an important research direction in the bearingless motor field. To realize a stable suspension for the BPMSM, accurate decoupling control between the electromagnetic torque and radial suspension force is indispensable. In this paper, a concise and reliable analysis method based on a magnetic field equivalent current is presented. By this analysis method, the operation principle is analyzed theoretically, and the necessary conditions to produce a stable radial suspension force are confirmed. In addition, mathematical models of the torque and radial suspension force are established which is verified by the finite element analysis (FEA software ANSYS. Finally, an experimental prototype of a 2-4 poles surface-mounted BPMSM is tested with the customized control strategy. The simulation and experimental results have shown that the motor has good rotation and suspension performance, and validated the accuracy of the proposed analysis method and the feasibility of the control strategy.

  11. Modulation of mu rhythm desynchronization during motor imagery by transcranial direct current stimulation

    Directory of Open Access Journals (Sweden)

    Kimura Akio

    2010-06-01

    Full Text Available Abstract Background The mu event-related desynchronization (ERD is supposed to reflect motor preparation and appear during motor imagery. The aim of this study is to examine the modulation of ERD with transcranial direct current stimulation (tDCS. Methods Six healthy subjects were asked to imagine their right hand grasping something after receiving a visual cue. Electroencephalograms (EEGs were recorded near the left M1. ERD of the mu rhythm (mu ERD by right hand motor imagery was measured. tDCS (10 min, 1 mA was used to modulate the cortical excitability of M1. Anodal, cathodal, and sham tDCS were tested in each subject with a randomized sequence on different days. Each condition was separated from the preceding one by more than 1 week in the same subject. Before and after tDCS, mu ERD was assessed. The motor thresholds (MT of the left M1 were also measured with transcranial magnetic stimulation. Results Mu ERD significantly increased after anodal stimulation, whereas it significantly decreased after cathodal stimulation. There was a significant correlation between mu ERD and MT. Conclusions Opposing effects on mu ERD based on the orientation of the stimulation suggest that mu ERD is affected by cortical excitability.

  12. Taxation of Fringe Benefits: Alternative Approaches to Current Problems.

    Science.gov (United States)

    Cohen, Anita E.

    1979-01-01

    The current IRS tax treatment of fringe benefits is seen as inadequate, and the judicial precept confusing, because groups of employee benefits are inappropriately excluded from taxation as perquisites. A tax equalization approach is proposed. Available from Suffolk University Law Review Office, 41 Temple St., Boston, MA 02114. (MSE)

  13. Teaching Electrical Energy, Voltage and Current: An Alternative Approach.

    Science.gov (United States)

    Licht, Pieter

    1991-01-01

    A program for teaching the concepts of electric energy, voltage, and current is proposed. The ideas and concepts are introduced in a sequence that places more emphasis on some aspects that are normally treated very briefly. A phenomenological orientation, qualitative and quantitative micro- and macroscopic treatments, and the inclusion of the…

  14. A novel current vector decomposition controller design for six-phase permanent magnet synchronous motor

    Institute of Scientific and Technical Information of China (English)

    袁雷; 胡冰新; 魏克银; 林莹

    2016-01-01

    The vector control algorithm based on vector space decomposition (VSD) transformation method has a more flexible control freedom, which can control the fundamental and harmonic subspace separately. To this end, a current vector decoupling control algorithm for six-phase permanent magnet synchronous motor (PMSM) is designed. Using the proposed synchronous rotating coordinate transformation matrix, the fundamental and harmonic components ind−q subspace are changed into direct current (DC) component, only using the traditional proportional integral (PI) controller can meet the non-static difference adjustment, and the controller parameter design method is given by employing internal model principle. In addition, in order to remove the 5th and 7th harmonic components of stator current, the current PI controller parallel with resonant controller is employed inx−y subspace to realize the specific harmonic component compensation. Simulation results verify the effectiveness of current decoupling vector controller.

  15. Evaluation of Starting Current of Induction Motors Using Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Iman Sadeghkhani

    2014-07-01

    Full Text Available Induction motors (IMs are widely used in industry including it be an electrical or not. However during starting period, their starting currents are so large that can damage equipment. Therefore, this current should be estimated accurately to prevent hazards caused by it. In this paper, the artificial neural network (ANN as an intelligent tool is used to evaluate starting current peak of IMs. Both Multilayer Perceptron (MLP and Radial Basis Function (RBF structures have been analyzed. Six learning algorithms, backpropagation (BP, delta-bar-delta (DBD, extended delta-bar-delta (EDBD, directed random search (DRS, quick propagation (QP, and levenberg marquardt (LM were used to train the MLP. The simulation results using MATLAB show that most developed ANNs can estimate the starting current peak of IMs with good accuracy. However, it is proven that LM and EDBD algorithms present better performance for starting current evaluation based on average of relative and absolute errors.

  16. Detection of mechanical failures in induction motors by current spectrum analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sokansky, K.; Novak, P.; Bilos, J.; Labaj, J. [Technical University Ostrava, Moraviasilesian Power Stations s.h.c. (Czech Republic)

    1997-12-31

    From the diagnostic point of view, an electric machine can be understood as an electromechanical system. It means that any manifestations of mechanical failures do not have to show themselves only in mechanical quantities, i.e. vibration in our case. Mechanical failures can also manifest themselves in electrical quantities, namely in electric current in our case. This statement is valid inversely too, which means that faults occurring in electric circuits can be measured through mechanical quantities. This presentation deals with measuring the current spectra of induction motors with short circuited armatures that are drives used in the industries most. (orig.) 3 refs.

  17. Analysis of energy cogeneration with alternative motors in a brewery; Analise de cogeracao de energia com motores alternativos em uma cervejaria

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Evelyn Ramiro; Almeida Silvio Carlos Anibal de [Universidade Federal do Rio de Janeiro (DEM/UFRJ), RJ (Brazil). Dept. de Engenharia Mecanica], E-mail: eng_evelyn@poli.ufrj.br

    2010-07-01

    In this study it will be presented a technical-economical simulation on a plant that needs thermal and electrical energy, simultaneously. This simulation analysis will be based on the economical and technical validity of the installation of a thermo electrical cogeneration power plant using alternative motors. The objective intends the electrical autonomy of use of thermal energy and the better plant efficiency, and lower CO{sub 2} emissions. This analysis will utilize the Cogeneration Read Reckoner, version 3.1 of the Sinclair Knight Merz.

  18. Alternating current calorimetry at very high pressure and low temperature

    CERN Document Server

    Wilhelm, H

    2002-01-01

    The specific heat of CePd sub 2 sub . sub 0 sub 2 Ge sub 1 sub . sub 9 sub 8 has been measured with an ac calorimetric technique up to 22 GPa for temperatures in the range 0.3 K <=T <=10 K. A thermocouple allowed the temperature oscillations to be read when an ac heating current was sent through the sample. The inverse of the thermovoltage V sub a sub c recorded at low temperature exhibits a pronounced anomaly as a function of pressure. It is shown that 1/V sub a sub c extrapolated to zero temperature is a measure of the Sommerfeld coefficient gamma.

  19. Josephson effects in an alternating current biased transition edge sensor

    CERN Document Server

    Gottardi, Luciano; Akamatsu, Hiroki; van der Kuur, Jan; Bruijn, Marcel P; Hartog, Roland H den; Hijmering, Richard; Khosropanah, Pourya; Lambert, Colin; van der Linden, Anton J; Ridder, Marcel L; Suzuki, Toyo; Gao, Jan R

    2016-01-01

    We report the experimental evidence of the ac Josephson effect in a transition edge sensor (TES) operating in a frequency domain multiplexer and biased by ac voltage at MHz frequencies. The effect is observed by measuring the non-linear impedance of the sensor. The TES is treated as a weakly linked superconducting system and within the resistively shunted junction model framework. We provide a full theoretical explanation of the results by finding the analytic solution of the non-inertial Langevian equation of the system and calculating the non-linear response of the detector to a large ac bias current in the presence of noise.

  20. Alternating Pulse Current in Electrocoagulation for Wastewater Treatment to Prevent the Passivation or Al Electrode

    Institute of Scientific and Technical Information of China (English)

    MAO Xuhui; HONG Song; ZHU Hua; LIN Hui; WEI Lin; GAN Fuxing

    2008-01-01

    A novel current feed style, alternating pulse current, was proposed in electrocoagulation aiming at preventing the passivation of electrode materials. The open circuit potential (OCP) measurements after anodic and cathodic potentiodynamic polarization showed that cathodic polarization could activate Al electrode. The surface of Al electrode after alternating pulse current electrocoagulation was investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), and the results indicate that passivation of Al is not observed. Furthermore, the simulated wastewater treatment tests show that alternating pulse current electrocoagulation has a visible energy saving effect and is worthy of generalization.

  1. Alternating Current All-electrical Gun Control System in Tanks

    Directory of Open Access Journals (Sweden)

    Zang Kemao

    2004-07-01

    Full Text Available The ac all-electrical gun control system is composed of permanent magnetic synchronous machine-drive control systems and the ball-screw by replacing the complicated electrohydraulic systems. At the same time, the variable-structure system with sliding modes makes the gun control systems to have higher performances using the only rate flexure gyroscope. Thereby, vehicle hull gyroscope and angular gyroscope are left out.The new ac all-electrical gun control systems developed are reduced by 40 per cent in weight, decreased by 30 per cent in volume, increased by 35 per cent in efficiency, and enhanced by three times in service life as compared to the current gun control systems.

  2. Transcranial direct current stimulation facilitates motor learning post-stroke: a systematic review and meta-analysis.

    Science.gov (United States)

    Kang, Nyeonju; Summers, Jeffery J; Cauraugh, James H

    2016-04-01

    Transcranial direct current stimulation (tDCS) is an attractive protocol for stroke motor recovery. The current systematic review and meta-analysis investigated the effects of tDCS on motor learning post-stroke. Specifically, we determined long-term learning effects by examining motor improvements from baseline to at least 5 days after tDCS intervention and motor practise. 17 studies reported long-term retention testing (mean retention interval=43.8 days; SD=56.6 days) and qualified for inclusion in our meta-analysis. Assessing primary outcome measures for groups that received tDCS and motor practise versus sham control groups created 21 valid comparisons: (1) 16 clinical assessments and (2) 5 motor skill acquisition tests. A random effects model meta-analysis showed a significant overall effect size=0.59 (plearning: (1) stimulation protocols: anodal on the ipsilesional hemisphere, cathodal on the contralesional hemisphere, or bilateral; (2) recovery stage: subacute or chronic stroke; (3) stimulation timing: tDCS before or during motor practise; and (4) task-specific training or conventional rehabilitation protocols. This robust meta-analysis identified novel long-term motor learning effects with tDCS and motor practise post-stroke.

  3. Diesel-alcohol-castor oil fuel blend as an alternative fuel for compression ignition motors; Misturas diesel-alcool-oleo de ricina como um combustivel alternativo para motores de ignicao por compressao

    Energy Technology Data Exchange (ETDEWEB)

    Peralta, Eduardo Gagliuffi; Bastos, Jose Guilherme R.R.; Barbosa, Cleiton Rubens Formiga [Rio Grande do Norte Univ., Natal, RN (Brazil). Centro de Tecnologia. Dept. de Engenharia Mecanica]. E-mail: eduardo@dem.ufrn.br

    2000-07-01

    This work evaluates some characteristics of the diesel-alcohol-castor oil ternary blends, where the castor oil is used as co-solvent viewing the using in compression ignition motors. The obtained results present the possibility of using those ternary blends as alternative fuels in compression ignition motors to be adopted in regions where the blend components are available.

  4. Emission Patterns under Alternative Congestion and Motor Vehicle Pollution Mitigation Policies in Shanghai

    Institute of Scientific and Technical Information of China (English)

    Chen Hongfeng; Li Fen; Li Xiangling

    2007-01-01

    As a megacity with thriving economy, Shanghai is experiencing rapid motorisation and confronted with traffic congestion problems despite its low car ownership. It is of value to look into the policies on emission control of motor vehicle and congestion reduction in such a city to explore how to reconcile mobility enhancement with the environment. Results of a dynamic simulation displayed time paths of emissions from motor vehicles in Shanghai over the period from 2000 to 2020. The simulation results showed that early policies on emission control of motor vehicle could bring about far-reaching effects on emission reduction, and take advantage of available low-polluting technologies and technical innovation over time. Travel demand management would play an important role in curbing congestion and reducing motor vehicle pollution by calming down car ownership rise and deterring inefficient trips as well as reducing fuel waste caused by congestion.

  5. Laser agitates probability flow in atoms to form alternating current and its peak-dip phenomenon

    CERN Document Server

    Cui, Huai-Yang

    2016-01-01

    By using trajectory-based approaches to quantum transition, it is found that laser can agitate the probability flow in atoms to form alternating current with the frequency of the laser. The detailed physical process of quantum transition is investigated, during which the alternating current in atomic probability flow becomes a key role connecting the external electromagnetic wave with the evolution of the quantum states in atoms. Computer was employed to simulate the physical process. The atomic alternating current may have the peak-dip phenomenon.

  6. Reduction of current chopping noise with DSP controller in switched reluctance motor drive system

    Institute of Scientific and Technical Information of China (English)

    郭伟; 詹琼华; 马志源

    2002-01-01

    A novel current chopping mode was used in a switched reluctance motor drive system to make full use of the characteristics of digital signal processor (DSP) TMS320F240. The necessity of this 180° phase-shift current control (PSCC) mode is introduced first and then the principle of PSCC covering both hardware requirement and software programming is described in detail. The analysis made indicated that with this mode, the chopping frequency in winding can reach 20 kHz with 10 kHz power switches and the control frequency can reach 40 kHz at the same time. Subsequently, based on the linear and nonlinear mathematical models of the switched reluctance motor ( SRM), some simulation work has been done. The simulation results show that when this mode is applied to SRM drive (SRD) system, the current waveform becomes better. So the ripple of the torque is reduced simultaneously and the vibration and acoustic noise are reduced involuntarily. Stationary tests show that the acoustic noise is greatly diminished. Finally, some experiments were made using a 50 kW SRD system for electric vehicle (EV). Experimental results indicate that this mode can be implemented feasibly and it has a good action on the SRD system.

  7. Improvement of immunoassay detection system by using alternating current magnetic susceptibility

    Science.gov (United States)

    Kawabata, R.; Mizoguchi, T.; Kandori, A.

    2016-03-01

    A major goal with this research was to develop a low-cost and highly sensitive immunoassay detection system by using alternating current (AC) magnetic susceptibility. We fabricated an improved prototype of our previously developed immunoassay detection system and evaluated its performance. The prototype continuously moved sample containers by using a magnetically shielded brushless motor, which passes between two anisotropic magneto resistance (AMR) sensors. These sensors detected the magnetic signal in the direction where each sample container passed them. We used the differential signal obtained from each AMR sensor's output to improve the signal-to-noise ratio (SNR) of the magnetic signal measurement. Biotin-conjugated polymer beads with avidin-coated magnetic particles were prepared to examine the calibration curve, which represents the relation between AC magnetic susceptibility change and polymer-bead concentration. For the calibration curve measurement, we, respectively, measured the magnetic signal caused by the magnetic particles by using each AMR sensor installed near the upper or lower part in the lateral position of the passing sample containers. As a result, the SNR of the prototype was 4.5 times better than that of our previous system. Moreover, the data obtained from each AMR sensor installed near the upper part in the lateral position of the passing sample containers exhibited an accurate calibration curve that represented good correlation between AC magnetic susceptibility change and polymer-bead concentration. The conclusion drawn from these findings is that our improved immunoassay detection system will enable a low-cost and highly sensitive immunoassay.

  8. Choice Of Input Data Type Of Artificial Neural Network To Detect Faults In Alternative Current Systems

    Directory of Open Access Journals (Sweden)

    T. Benslimane

    2006-01-01

    Full Text Available This paper present a study on different input data types of ANN used to detect faults such as over-voltage in AC systems (AC network , induction motor. The input data of ANN are AC voltage and current. In no fault condition, voltage and current are sinusoidal. The input data of the ANN may be the instantaneous values of voltage and current, their RMS values or their average values after been rectified. In this paper we presented different characteristics of each one of these data. A digital software C++ simulation program was developed and simulation results were presented.

  9. Performance evaluation of directly photovoltaic powered DC PM (direct current permanent magnet) motor – propeller thrust system

    International Nuclear Information System (INIS)

    Photovoltaic (PV) powered directly coupled electro-mechanical system has wide applications (e.g. PV powered cooling fans in green houses, PV water pumping system, solar vehicles). The objective of this work is to analyse the operation of directly PV powered DC PM (direct current permanent magnet) motor – propeller system for selection of motor parameters. The performance of such system mainly depends on the incident solar radiation, operating cell temperature, DC motor and propeller load parameters. It is observed that the operating points of the PV DC PM motor – propeller system matches very closely with the maximum power points (MPPs) of the PV array, if the DC PM motor – propeller parameters have been properly selected. It is found that for a specific application of such type of system, matching of torque–speed operating points with respect to the maximum power points of PV array are very important. It is ascertained through results that the DC PM motor's armature resistance, magnetic field constant, starting current to overcome the starting torque and torque coefficient are the main parameters. In designing a PV powered DC PM motor for a specific application, selection of these parameters are important for maximum utilization of the PV array output. The results of this system are useful for designing of directly PV powered DC PM motor's for aerodynamic applications. - Highlights: • We analyse the performance of directly PV powered DC PM motor – propeller system. • We examine PV electro-mechanical system for selection of DC motor parameters. • Matching of torque–speed curve to maximum power points of PV array is important

  10. Comparison of Output Current Ripple in Single and Dual Three-Phase Inverters for Electric Vehicle Motor Drives

    Directory of Open Access Journals (Sweden)

    Jelena Loncarski

    2015-04-01

    Full Text Available The standard solution for the traction system in battery powered electric vehicles (EVs is a two-level (2L inverter feeding a three-phase motor. A simple and effective way to achieve a three-level (3L inverter in battery-supplied electric vehicles consists of using two standard three-phase 2L inverters with the open-end winding connection of standard three-phase ac motors. The 3L inverter solution can be usefully adopted in EVs since it combines several benefits such as current ripple reduction, increment of phase motor voltage with limited voltage ratings of the two battery banks, improvement in system reliability, etc. The reduction in current ripple amplitude is particularly relevant since it is a source of electromagnetic interference and audio noise from the inverter-motor power connection cables and from the motor itself. By increasing the inverter switching frequency the ripple amplitude is reduced, but the drive efficiency decreases due to the proportionally increased switching losses. In this paper the peak-to-peak ripple amplitude of the dual-2L inverter is evaluated and compared with the corresponding ripple of the single-2L inverter, considering the same voltage and power motor ratings. The ripple analysis is carried out as a function of the modulation index to cover the whole modulation range of the inverter, and the theoretical results are verified with experimental tests carried out by an inverter-motor drive prototype.

  11. Impact Analysis of Dwell Angles on Current Shape and Torque in Switched Reluctance Motors

    Directory of Open Access Journals (Sweden)

    Syeda Fatima Ghousia

    2012-03-01

    Full Text Available The reduction of torque ripple is the main target in research for designing a variable drive system with switched reluctance motors (SRM for higher torque density and better efficiency. This ripple is due to the transition of excitation current between the adjacent phases. Precise control of turn-on and turn off angle is required to smooth the torque. In this paper, the effects of selecting the turn-on and turn-off angles are simulated in detail. It is observed that with the extended turn-on and turn off angles, the precise selection of turn-on and turn off angle can alter the shape of the excitation current in the stator coil and its point of overlapping with the adjacent coil. Therefore the transition between different phases can be smoothed out. The impact of this alteration on the excitation current and torque ripple as a function of different parameters of dwell angle is studied in detail in this paper. It is found that a sinusoidal current shape can also be obtained with the proper selection of these parameters.

  12. Speed Control of Brushless Dc Motor Using Current Fed Quasi Z-source Inverter with Regeneration Capability

    Directory of Open Access Journals (Sweden)

    A. Santhi Mary Antony

    2015-06-01

    Full Text Available Current fed Quasi Z-Source Inverters (qZSI have the advantages of voltage buck-boost capability, improved reliability, reduced passive component ratings, continuous input current, a common dc rail between source and inverter and unique regeneration capability. This current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. Since current fed quasi Z Source Inverter has many advantages it can be employed for motor drive applications such as Brushless DC motor (BLDC drive. Therefore this study proposes the use of qZSI for BLDC motor. The simulation results for the same are presented in this study.

  13. Note: Fast compact laser shutter using a direct current motor and three-dimensional printing

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Grace H., E-mail: ghzhang0@mit.edu; Braverman, Boris; Kawasaki, Akio; Vuletić, Vladan [Department of Physics, MIT-Harvard Center for Ultracold Atoms and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-12-15

    We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade’s range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than 10{sup 8} cycles.

  14. Note: Fast compact laser shutter using a direct current motor and three-dimensional printing

    International Nuclear Information System (INIS)

    We present a mechanical laser shutter design that utilizes a direct current electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade’s range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 ± 0.02) m/s with 1 ms activation delay and 10 μs jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than 108 cycles

  15. Method and apparatus for reducing the harmonic currents in alternating-current distribution networks

    Science.gov (United States)

    Beverly, Leon H.; Hance, Richard D.; Kristalinski, Alexandr L.; Visser, Age T.

    1996-01-01

    An improved apparatus and method reduce the harmonic content of AC line and neutral line currents in polyphase AC source distribution networks. The apparatus and method employ a polyphase Zig-Zag transformer connected between the AC source distribution network and a load. The apparatus and method also employs a mechanism for increasing the source neutral impedance of the AC source distribution network. This mechanism can consist of a choke installed in the neutral line between the AC source and the Zig-Zag transformer.

  16. Minimization and identification of conducted emission bearing current in variable speed induction motor drives using PWM inverter

    Indian Academy of Sciences (India)

    A Ramachandran; M Channa Reddy; Ranjan Moodithaya

    2008-10-01

    The recent increase in the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applicatons in process and aerospace industries, but due to fast switching of the modern power electronic devices, the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrical instruments and give rise to the flow of bearing current in the induction motor. Due to the flow of bearing current in the induction motor, electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the conducted and radiated emissions become a major concern. In this paper, identification of bearing current due to conducted emission, the measurement of bearing current in a modified induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line impedance stabilization network (LISN)), the electronics interface circuits are used to measure high frequency common mode current, bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at the same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with frequency Vs, line voltage in $dB{_\\mu} V$, common mode voltage in $dB{_\\mu} V$ and the bearing current in $dB_{\\mu} A$ with out and with minimizing circuits.

  17. Effect of decreasing electrical resistance in Characeae cell membranes caused by the flow of alternating current

    Directory of Open Access Journals (Sweden)

    Edward Śpiewla

    2014-02-01

    Full Text Available By means of the techniques of external electrodes and microelectrodes, it was found that evanescent flow of an alternating current through plasmalemma of Characeae cells neutralises oscillatory change in their electrical resistance and reversibly diminishes its value. This effect is particularly significant in the case of "high resistance cells", but it weakens with increasing temperature. The value of the estimated activation energy indicates that, after flow of the alternating current through the membrane, a rapid increase in the conductivity may be caused by an increase in conductivity of potassium channels. This result seems to support the hypothesis of electroconformational feedback.

  18. On the possible role of stimulation duration for after-effects of transcranial alternating current stimulation

    OpenAIRE

    Stefan Rach; Toralf Neuling; Herrmann, Christoph S.

    2015-01-01

    Transcranial alternating current stimulation is a novel method that allows application of sinusoidal currents to modulate brain oscillations and cognitive processes. Studies in humans have demonstrated tACS after-effects following stimulation durations in the range of minutes. However, such after-effects are absent in animal studies using much shorter stimulation protocols in the range of seconds. Thus, stimulation duration might be a critical parameter for after-effects to occur. To test thi...

  19. An investigation of the dynamic behaviors of an MRE isolator subjected to constant and alternating currents

    Science.gov (United States)

    Shi, H. F.; Yu, M.; Zhu, M.; Fu, J.; Choi, S. B.; Xing, Z. W.

    2016-07-01

    This paper presents the dynamic behaviors of a magneto-rheological elastomer (MRE) isolator by applying constant and time-varying exciting currents. As the first step, a shear type of the MRE isolator is devised with a simplified design. Then, the distributions of the magnetic field in the MRE isolator under both constant and alternating exciting currents are analyzed by commercial software (ANSYS). Subsequently, the dynamic performances of the isolator are experimentally evaluated by applying three different inputs: constant, square and sinusoidal exciting current. It has been identified from the experimental results that the constant exciting current can provide optimal performances in static control, while the MRE isolator presents more advantages in dynamic control with the sine wave current excitation. This means that an attenuation coefficient of alternating current should be considered to achieve a better dynamic control effect. On the other hand, it has also been demonstrated that alternating the magnetic field can provide a broader variable range of the viscous damping coefficient than that under constant magnetic field.

  20. Effect of Modulated Alternating and Direct Current Iontophoresis on Transdermal Delivery of Lidocaine Hydrochloride

    Directory of Open Access Journals (Sweden)

    Gaurav Bhatia

    2014-01-01

    Full Text Available The objective of this study was to investigate the iontophoretic delivery of lidocaine hydrochloride through porcine skin and to compare the effects of modulated alternating and direct current iontophoresis. Continuous and modulated iontophoresis was applied for one hour and two hours (0-1 h and 4-5th h using a 1% w/v solution of lidocaine hydrochloride. Tape stripping was done to quantify the amount of drug permeated into stratum corneum and skin extraction studies were performed to determine the amount of drug in stripped skin. Receptor was sampled and analyzed over predefined time periods. The amount of lidocaine delivered across porcine skin after modulated direct current iontophoresis for 2 h was 1069.87±120.03 μg/sq·cm compared to 744.81±125.41 μg/sq·cm after modulated alternating current iontophoresis for 2 h. Modulated direct current iontophoresis also enhanced lidocaine delivery by twelvefold compared to passive delivery as 91.27±18.71 μg/sq·cm of lidocaine was delivered after passive delivery. Modulated iontophoresis enhanced the delivery of lidocaine hydrochloride across porcine skin compared to the passive delivery. Modulated alternating current iontophoresis for duration of 2 h at frequency of 1 kHz was found to be comparable to the continuous direct current iontophoresis for 1 h.

  1. Studying Effects of Transcranial Alternating Current Stimulation on Hearing and Auditory Scene Analysis

    NARCIS (Netherlands)

    Riecke, Lars

    2016-01-01

    Recent studies have shown that perceptual detection of near-threshold auditory events may depend on the relative timing of the event and ongoing brain oscillations. Furthermore, transcranial alternating current stimulation (tACS), a non-invasive and silent brain stimulation technique, can entrain co

  2. A simple and efficient alternative to implementing systematic random sampling in stereological designs without a motorized microscope stage.

    Science.gov (United States)

    Melvin, Neal R; Poda, Daniel; Sutherland, Robert J

    2007-10-01

    When properly applied, stereology is a very robust and efficient method to quantify a variety of parameters from biological material. A common sampling strategy in stereology is systematic random sampling, which involves choosing a random sampling [corrected] start point outside the structure of interest, and sampling relevant objects at [corrected] sites that are placed at pre-determined, equidistant intervals. This has proven to be a very efficient sampling strategy, and is used widely in stereological designs. At the microscopic level, this is most often achieved through the use of a motorized stage that facilitates the systematic random stepping across the structure of interest. Here, we report a simple, precise and cost-effective software-based alternative to accomplishing systematic random sampling under the microscope. We believe that this approach will facilitate the use of stereological designs that employ systematic random sampling in laboratories that lack the resources to acquire costly, fully automated systems.

  3. DSP-Based Sensorless Speed Control of a Permanent Magnet Synchronous Motor using Sliding Mode Current Observer

    Directory of Open Access Journals (Sweden)

    Rachid Askour

    2014-05-01

    Full Text Available In this paper, experimental results of 3-phase permanent magnet synchronous motor (PMSM sensorless speed control are presented. To estimate the rotor position, a sliding mode current observer (SMCO was implemented. This observer estimates the back emfs of the motor in the stationary reference frame using only the measured voltages and currents of the motor. These emfs were utilized to obtain the rotor position. The speed of the motor was calculated by differentiating the rotor position angle. The stability of the proposed SMCO was verified using Lyapunov method to determine the observer gain. The saturation function was adopted in order to reduce the chattering phenomenon caused by the SMCO. A vector control method was employed to achieve the sensorless drive system. The control application was developed in C/C++ language and implemented using the Texas Instruments TMS320LF2812 digital signal processor (DSP. This new processor enables intelligent control for motors. We used to test the drive the MCK2812 which is a professional development kit available from Technosoft Company. The theoretical finding is validated with experimental results that show the effectiveness of the real-time implementation.

  4. Adding effect of current displacement and magnetic circuit saturation in an asynchronous motor mathematical model

    Directory of Open Access Journals (Sweden)

    I.A. Tsodik

    2014-04-01

    Full Text Available A methodology of an asynchronous motor mathematical model synthesis is described. Experiments are suggested to be conducted in the following sequence. Geometrical models are first built in AutoCAD, then imported to Comsol Multiphysics, and further processed in Matlab with computation of coefficients and dependences applied in the asynchronous motor mathematical model.

  5. Parameter Estimation of Inverter and Motor Model at Standstill using Measured Currents Only

    DEFF Research Database (Denmark)

    Rasmussen, Henrik; Knudsen, Morten; Tønnes, M.

    1996-01-01

    Methods for estimation of the parameters in the electrical equivalent diagram for the induction motor, based on special designed experiments, are given. In all experriments two of the three phases are given the same potential, i.e., no net torque is generatedand the motor is at standstill. Input...

  6. Alternate but do not swim: a test for executive motor dysfunction in Parkinson disease.

    Science.gov (United States)

    Falchook, Adam D; Decio, Danilo; Williamson, John B; Okun, Michael S; Malaty, Irene A; Rodriguez, Ramon L; Heilman, Kenneth M

    2011-07-01

    The objective of this study is to learn if participants with Parkinson disease (PD), when compared to normal controls, are impaired in making simultaneous but independent right and left hand movements. Participants were tested with Luria's Alternating Hand Postures (AHP) test and modified AHP tests. Twelve PD participants without dementia and twelve matched controls were assessed for their ability to perform the parallel AHP test (both hands remaining in the same coronal plane) and with modifications of this test into swimming (alternative arm extension with finger extension and arm flexion with finger flexion) and reverse swimming (alternative arm extension-finger flexion and arm flexion-finger extension) movements. The participants with PD were significantly impaired when performing the parallel and the reverse swimming movements AHP tests, but not impaired on the swimming movements AHP test. Swimming movements may be phylogenetically and ontogenetically more primitive and not as heavily dependent on frontal-basal ganglia networks; thus performance of swimming movements during the parallel AHP test may decrease this test's sensitivity. PMID:22882811

  7. Motor current signature analysis detects airgap eccentricity problems in 3.3 kV 670 HP induction motor driven pumps

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, W.T. [EM Diagnostics Ltd., Alford, Scotland (United Kingdom)

    2005-07-01

    This paper presented industrial case histories to demonstrate the application of Motor Current Signature Analysis (MCSA) to reliably detect airgap eccentricity in 3-phase induction motors. Two types of airgap eccentricity exist simultaneously. The first is static eccentricity where the position of minimum radial airgap length is fixed, and the second is dynamic eccentricity where the minimum airgap revolves with the rotor and is a function of space and time. The causes of both types of airgap eccentricity were described along with the differences between the two. The resultant steady force on the rotor in one direction called unbalanced magnetic pull was also discussed along with the unique frequency components in the airgap flux waveform which induce current components in the stator winding. It was noted that if the level of airgap eccentricity is not kept within a specified limit, then both types of eccentricity cause excessive stressing of the motor resulting in increased bearing wear. In addition, the radial magnetic force waves produced by eccentricity also act on the stator core assembly and rotor cage, thereby subjecting the stator and rotor windings to harmful vibration. MCSA was used to identify the characteristic current signature pattern that indicates abnormal levels of airgap eccentricity. An equation used to identify the current signature pattern was presented. The magnitudes of the rotor slot passing frequency components are a function of airgap eccentricity and are also affected by other factors such as rotor slot design, rotor bar skew, magnetic saturation, magneto motive force distribution, operating load, stator winding asymmetry, stator winding impedance, and voltage supply unbalance. It was concluded that MCSA can reliably detect unacceptable running levels of airgap eccentricity. The technology can be assessed by a hand held and user friendly MCSA instrument called the Iris CS Meter, which has on-line diagnostics to detect broken rotor bars

  8. Alternating-current and direct-current responses of light-emitting devices based on decacyclene Langmuir-Blodgett films

    Energy Technology Data Exchange (ETDEWEB)

    Das, S.; Chowdhury, A.; Pal, A.J. [Indian Association for the Cultivation of Science, Jadavpur, Calcutta (India). Dept. of Solid State Physics

    2001-06-16

    Light-emitting devices have been fabricated with Langmuir-Blodgett films of decacyclene. The devices have been operated under both direct-current (dc) and alternating-current (ac) modes. Frequency response of luminance of such devices under ac voltage has been studied, and moderately high-frequency electroluminescence has been observed from these devices. Light output characteristics, charge injection, and operation mechanism under the two modes have been compared and found to be different. Fowler-Nordheim tunneling mechanism has been found to be applicable in the dc case, and space-charge-assisted electron injection lowered the tunneling barrier ac modes. The transient characteristics of luminance have been studied which supported the role of space charges in device operation. (orig.)

  9. Use of biosensors as alternatives to current regulatory methods for marine biotoxins.

    Science.gov (United States)

    Vilariño, Natalia; Fonfría, Eva S; Louzao, M Carmen; Botana, Luis M

    2009-01-01

    Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids) in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in European food and there are no legal requirements or technical approaches available to identify their presence. The need for alternative methods to the bioassay is clearly important, and biosensors have become in recent years a feasible alternative to animal sacrifice. This review will discuss the advantages and disadvantages of using biosensors as alternatives to animal assays for marine toxins, with particular focus on surface plasmon resonance (SPR) technology.

  10. Use of Biosensors as Alternatives to Current Regulatory Methods for Marine Biotoxins

    Directory of Open Access Journals (Sweden)

    Luis M. Botana

    2009-11-01

    Full Text Available Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in European food and there are no legal requirements or technical approaches available to identify their presence. The need for alternative methods to the bioassay is clearly important, and biosensors have become in recent years a feasible alternative to animal sacrifice. This review will discuss the advantages and disadvantages of using biosensors as alternatives to animal assays for marine toxins, with particular focus on surface plasmon resonance (SPR technology.

  11. Effects of alternating and direct current in electrocoagulation process on the removal of cadmium from water

    Energy Technology Data Exchange (ETDEWEB)

    Vasudevan, Subramanyan, E-mail: vasudevan65@gmail.com [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India); Lakshmi, Jothinathan; Sozhan, Ganapathy [CSIR-Central Electrochemical Research Institute, Karaikudi 630 006 (India)

    2011-08-15

    Highlights: {yields} Very high removal efficiency of cadmium was achieved by electrocoagulation. {yields} Alternating current (AC) avoids oxide layer and corrosion on anode surface. {yields} Good current transfer between anode and cathode results more removal efficiency. {yields} Compact treatment facility and complete automation. {yields} Aluminum alloy anode prevents residual aluminum in treated water. - Abstract: In practice, direct current (DC) is used in an electrocoagulation processes. In this case, an impermeable oxide layer may form on the cathode as well as corrosion formation on the anode due to oxidation. This prevents the effective current transfer between the anode and cathode, so the efficiency of electrocoagulation processes declines. These disadvantages of DC have been diminished by adopting alternating current (AC) in electrocoagulation processes. The main objective of this study is to investigate the effects of AC and DC on the removal of cadmium from water using aluminum alloy as anode and cathode. The results showed that the removal efficiency of 97.5 and 96.2% with the energy consumption of 0.454 and 1.002 kWh kl{sup -1} was achieved at a current density of 0.2 A/dm{sup 2} and pH of 7.0 using aluminum alloy as electrodes using AC and DC, respectively. For both AC and DC, the adsorption of cadmium was preferably fitting Langmuir adsorption isotherm, the adsorption process follows second order kinetics and the temperature studies showed that adsorption was exothermic and spontaneous in nature.

  12. Eyes wide shut: Transcranial alternating current stimulation drives alpha rhythm in a state dependent manner

    OpenAIRE

    Philipp Ruhnau; Toralf Neuling; Marco Fuscá; Herrmann, Christoph S.; Gianpaolo Demarchi; Nathan Weisz

    2016-01-01

    Transcranial alternating current stimulation (tACS) is used to modulate brain oscillations to measure changes in cognitive function. It is only since recently that brain activity in human subjects during tACS can be investigated. The present study aims to investigate the phase relationship between the external tACS signal and concurrent brain activity. Subjects were stimulated with tACS at individual alpha frequency during eyes open and eyes closed resting states. Electrodes were placed at Cz...

  13. Impact of cercal air currents on singing motor pattern generation in the cricket (Gryllus bimaculatus DeGeer).

    Science.gov (United States)

    Jacob, Pedro F; Hedwig, Berthold

    2015-11-01

    The cercal system of crickets detects low-frequency air currents produced by approaching predators and self-generated air currents during singing, which may provide sensory feedback to the singing motor network. We analyzed the effect of cercal stimulation on singing motor pattern generation to reveal the response of a singing interneuron to predator-like signals and to elucidate the possible role of self-generated air currents during singing. In fictive singing males, we recorded an interneuron of the singing network while applying air currents to the cerci; additionally, we analyzed the effect of abolishing the cercal system in freely singing males. In fictively singing crickets, the effect of short air stimuli is either to terminate prematurely or to lengthen the interchirp interval, depending on their phase in the chirp cycle. Within our stimulation paradigm, air stimuli of different velocities and durations always elicited an inhibitory postsynaptic potential in the singing interneuron. Current injection in the singing interneuron elicited singing motor activity, even during the air current-evoked inhibitory input from the cercal pathway. The disruptive effects of air stimuli on the fictive singing pattern and the inhibitory response of the singing interneuron point toward the cercal system being involved in initiating avoidance responses in singing crickets, according to the established role of cerci in a predator escape pathway. After abolishing the activity of the cercal system, the timing of natural singing activity was not significantly altered. Our study provides no evidence that self-generated cercal sensory activity has a feedback function for singing motor pattern generation.

  14. Effects of direct and alternating current on the treatment of oily water in an electroflocculation process

    OpenAIRE

    A. A. Cerqueira; P. S. A. Souza; M. R. C. Marques

    2014-01-01

    In the direct current mode (DC), widely used in electroflocculation (EC), the formation of an impermeable oxide layer on the cathode causes the declining of the efficiency of this process. This disadvantage has been reduced by adopting alternating current (AC). In this study, the effects of AC and DC on operational parameters such as the removal of oils and greases (O&G), color and turbidity from oil-in-water (O/W) emulsions of the petroleum industry using aluminum electrodes were investigate...

  15. Mixed eccentricity diagnosis in Inverter-Fed Induction Motors via the Adaptive Slope Transform of transient stator currents

    Science.gov (United States)

    Pons-Llinares, J.; Antonino-Daviu, J.; Roger-Folch, J.; Moríñigo-Sotelo, D.; Duque-Pérez, O.

    2014-10-01

    This paper researches the detection of mixed eccentricity in Inverter-Fed Induction Motors. The classic FFT method cannot be applied when the stator current captured is not in steady state, which is very common in these motors. Therefore, a transform able to detect the time-frequency evolutions of the components present in the transient signal captured must be applied. In order to optimize the result, a method to calculate the theoretical time-frequency evolution of the stator current components is presented, using only the captured current. This previously obtained information enables the use of the proposed transform: the Adaptive Slope Transform, based on appropriately choosing the atom slope in each point analyzed. Thanks to its adaptive characteristics, the time-frequency evolution of the main components in a stator transient current is traced precisely and with high detail in the 2D time-frequency plot obtained. As a consequence, the time-frequency plane characteristic patterns produced by the Eccentricity Related Harmonics are easily and clearly identified enabling a reliable diagnosis. Moreover, the problem of quantifying the presence of the fault is solved presenting a simple and easy to apply method. The transform capabilities have been shown successfully diagnosing an Inverter-Fed Induction Motor with mixed eccentricity during a startup, a decrease in the assigned frequency, and a load variation with and without slip compensation.

  16. Anodal transcranial direct current stimulation enhances the effects of motor imagery training in a finger tapping task.

    Science.gov (United States)

    Saimpont, Arnaud; Mercier, Catherine; Malouin, Francine; Guillot, Aymeric; Collet, Christian; Doyon, Julien; Jackson, Philip L

    2016-01-01

    Motor imagery (MI) training and anodal transcranial direct current stimulation (tDCS) applied over the primary motor cortex can independently improve hand motor function. The main objective of this double-blind, sham-controlled study was to examine whether anodal tDCS over the primary motor cortex could enhance the effects of MI training on the learning of a finger tapping sequence. Thirty-six right-handed young human adults were assigned to one of three groups: (i) who performed MI training combined with anodal tDCS applied over the primary motor cortex; (ii) who performed MI training combined with sham tDCS; and (iii) who received tDCS while reading a book. The MI training consisted of mentally rehearsing an eight-item complex finger sequence for 13 min. Before (Pre-test), immediately after (Post-test 1), and at 90 min after (Post-test 2) MI training, the participants physically repeated the sequence as fast and as accurately as possible. An anova showed that the number of sequences correctly performed significantly increased between Pre-test and Post-test 1 and remained stable at Post-test 2 in the three groups (P < 0.001). Furthermore, the percentage increase in performance between Pre-test and Post-test 1 and Post-test 2 was significantly greater in the group that performed MI training combined with anodal tDCS compared with the other two groups (P < 0.05). As a potential physiological explanation, the synaptic strength within the primary motor cortex could have been reinforced by the association of MI training and tDCS compared with MI training alone and tDCS alone. PMID:26540137

  17. Optimization of brushless direct current motor design using an intelligent technique.

    Science.gov (United States)

    Shabanian, Alireza; Tousiwas, Armin Amini Poustchi; Pourmandi, Massoud; Khormali, Aminollah; Ataei, Abdolhay

    2015-07-01

    This paper presents a method for the optimal design of a slotless permanent magnet brushless DC (BLDC) motor with surface mounted magnets using an improved bee algorithm (IBA). The characteristics of the motor are expressed as functions of motor geometries. The objective function is a combination of losses, volume and cost to be minimized simultaneously. This method is based on the capability of swarm-based algorithms in finding the optimal solution. One sample case is used to illustrate the performance of the design approach and optimization technique. The IBA has a better performance and speed of convergence compared with bee algorithm (BA). Simulation results show that the proposed method has a very high/efficient performance. PMID:25841938

  18. Transcranial alternating current stimulation with sawtooth waves: simultaneous stimulation and EEG recording

    Directory of Open Access Journals (Sweden)

    James eDowsett

    2016-03-01

    Full Text Available Transcranial alternating current stimulation (tACS has until now mostly been administered as an alternating sinusoidal wave. Despite modern tACS stimulators being able to deliver alternating current with any arbitrary shape there has been no systematic exploration into the relative benefits of different waveforms. As tACS is a relatively new technique there is a huge parameter space of unexplored possibilities which may prove superior or complimentary to the traditional sinusoidal waveform. Here we begin to address this with an investigation into the effects of sawtooth wave tACS on individual alpha power. Evidence from animal models suggests that the gradient and direction of an electric current should be important factors for the subsequent neural firing rate; we compared positive and negative ramp sawtooth waves to test this. An additional advantage of sawtooth waves is that the resulting artefact in the electroencephalogram (EEG recording is significantly simpler to remove than a sine wave; accordingly we were able to observe alpha oscillations both during and after stimulation.We found that positive ramp sawtooth, but not negative ramp sawtooth, significantly enhanced alpha power during stimulation relative to sham (p<0.01. In addition we tested for an after-effect of both sawtooth and sinusoidal stimulation on alpha power but in this case did not find any significant effect. This preliminary study paves the way for further investigations into the effect of the gradient and direction of the current in tACS which could significantly improve the usefulness of this technique.

  19. Continuous electromagnetic separation of inclusion from aluminum melt using alternating current

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A novel scheme about the continuous electromagnetic purification of aluminum melt was put forward based on the utilization of a square separation pipe and a 50 Hz alternating current to produce electromagnetic force. It is experimentally found that with electrical current of 400 A/cm2, it takes only 10 s to remove 95% inclusion from aluminum melt. Comprehensive numerical simulations were carried out to investigate the dynamics mechanisms behind the process. The results show that the removal of inclusion is attributed to the cooperative effects of electromagnetic buoyancy and the secondary flow induced by the rotational electromagnetic force, and the removal efficient increases with the size of inclusion and the electrical current imposed. Theoretical predictions on the distribution and removal efficiency of inclusion were supported by the experiments.

  20. Fault detection and diagnosis of permanent-magnetic DC motors based on current analysis and BP neural networks

    Institute of Scientific and Technical Information of China (English)

    LIU Man-lan; ZHU Chun-bo; WANG Tie-cheng

    2005-01-01

    In order to guarantee quality during mass serial production of motors, a convenient approach on how to detect and diagnose the faults of a permanent-magnetic DC motor based on armature current analysis and BP neural networks was presented in this paper. The fault feature vector was directly established by analyzing the armature current. Fault features were extracted from the current using various signal processing methods including Fourier analysis, wavelet analysis and statistical methods. Then an advanced BP neural network was used to finish decision-making and separate fault patterns. Finally, the accuracy of the method in this paper was verified by analyzing the mechanism of faults theoretically. The consistency between the experimental results and the theoretical analysis shows that four kinds of representative faults of low power permanent-magnetic DC motors can be diagnosed conveniently by this method. These four faults are brush fray, open circuit of components, open weld of components and short circuit between armature coils. This method needs fewer hardware instruments than the conventional method and whole procedures can be accomplished by several software packages developed in this paper.

  1. Alternate current interference in pipeline; Interferencia por corrente alternada em dutos

    Energy Technology Data Exchange (ETDEWEB)

    Oliver, Joao Hipolito de Lima [TRANSPETRO - PETROBRAS Transporte S.A., Rio de Janeiro, RJ (Brazil)

    2003-07-01

    This paper regards to the concerning that the pipeline operators should take in to account to better understand and control the alternate current interference (AC- interference). Pipelines sharing rights-of-way with AC high voltage power lines are subjected to AC interference that can cause risk for personnel, operational safety and environment. The AC-interference shall be evaluated, in such way that mitigating action can be applied in order to assure the pipeline is operated in a safety way. The AC-interference evaluation should take in to account the pipeline and the electrical generation/transmission design data. Three approaches are considered: the coating integrity, the personnel chock hazards and the pipeline integrity. The coating integrity is affected by the possibility of high-voltage be induced on the pipeline during power line current fault. The operation and maintenance personnel can be prone to chock hazards (touch voltage and step voltage), depending upon the level of the induced voltage on the pipeline and the ground current. An induced voltage evaluation is then necessary to identify AC potentials in pipeline higher than the safe criteria. The pipeline integrity is concerning to the possibility of occurring alternate current corrosion (AC-corrosion) on the pipe wall. This kind of corrosion is still been investigated, and although it is less critical than the direct current corrosion, it can happen in specific situation. Parameters that affect AC-corrosion are discussed in this paper. Finely it is presented a brief guide to evaluate the possibility of occurring AC- interference in a pipeline and a mitigation measures summary. (author)

  2. Alternating Current Cloud Point Extraction on a Microfluidic Chip: the Use of Ferrocenyl Surfactants.

    Science.gov (United States)

    Usui, Yuya; Sasaki, Naoki

    2016-01-01

    Alternating current cloud point extraction (ACPE) is a preconcentration technique that can be employed in the analysis of membrane proteins on a microfluidic chip. However, the selectivity of ACPE relies on the hydrophobicity of the analytes. In this study, 11-ferrocenyltrimethylundecylammonium bromide (FTMA) was utilized to introduce electrostatic interaction as part of the ACPE technique. The use of ACPE with oxidized FTMA resulted in efficient concentration of fluorescently labeled anionic membrane proteins. We expect the approach outlined in this report to be useful in the preconcentration technique of microchip electrophoresis.

  3. Electrical Motor Current Signal Analysis using a Modulation Signal Bispectrum for the Fault Diagnosis of a Gearbox Downstream

    International Nuclear Information System (INIS)

    Motor current signal analysis has been an effective way for many years of monitoring electrical machines themselves. However, little work has been carried out in using this technique for monitoring their downstream equipment because of difficulties in extracting small fault components in the measured current signals. This paper investigates the characteristics of electrical current signals for monitoring the faults from a downstream gearbox using a modulation signal bispectrum (MSB), including phase effects in extracting small modulating components in a noisy measurement. An analytical study is firstly performed to understand amplitude, frequency and phase characteristics of current signals due to faults. It then explores the performance of MSB analysis in detecting weak modulating components in current signals. Experimental study based on a 10kw two stage gearbox, driven by a three phase induction motor, shows that MSB peaks at different rotational frequencies can be based to quantify the severity of gear tooth breakage and the degrees of shaft misalignment. In addition, the type and location of a fault can be recognized based on the frequency at which the change of MSB peak is the highest among different frequencies.

  4. Dynamics of single vortex line in the field of external alternative current

    International Nuclear Information System (INIS)

    Motion of a single vortex line in steady state under action of an external force due to alternate transport current, viscosity and pinning forces as well as the Magnus force has been investigated. The presence of the effective vortex mass was also taken into account. The vibrational spectrum of the line had two branches: the low- and high-frequency ones. The latter branch appears due to taking the effective vortex mass into consideration. In present report, the absorption of energy by the vortex, depending on the frequency of external transport current, has been calculated. The frequency dependence of the absorption demonstrates two typical resonance maxima, one of them being due to depinning frequency of the vortex, and the other one due to its cyclotron resonance. The influences of other forces on dynamics of the single vortex line were considered

  5. Combined transcranial direct current stimulation and homebased occupational therapy of upper limb motor impairment following intracerebral hemorrhage

    DEFF Research Database (Denmark)

    Mortensen, Jesper; Figlewski, Krystian; Andersen, Henning

    2016-01-01

    Purpose: To investigate the combined effect of transcranial direct current stimulation (tDCS) andhome-based occupational therapy on activities of daily living (ADL) and grip strength, inpatients with upper limb motor impairment following intracerebral hemorrhage (ICH). Methods:A double......-blind randomized controlled trial with one-week follow-up. Patients received fiveconsecutive days of occupational therapy at home, combined with either anodal (n ¼ 8) orsham (n ¼ 7) tDCS. The primary outcome was ADL performance, which was assessed with theJebsen–Taylor test (JTT). Results: Both groups improved JTT...... group, from baseline to post-assessment (p ¼ 0.158). Conclusions: Fiveconsecutive days of tDCS combined with occupational therapy provided greater improvementsin grip strength compared with occupational therapy alone. tDCS is a promising add-onintervention regarding training of upper limb motor...

  6. MINITYPE MACHINING SYSTEM FOR DIAMOND LAPPING & POLISHING BY USING BRUSHLESS DIRECT CURRENT MOTOR AS PRECISE SPINDLE

    Institute of Scientific and Technical Information of China (English)

    FU Huinan; CHEN Dongsheng; ZHAO Yong; LIN Binquan

    2008-01-01

    A minitype precise spindle system which can machine precisely and stably in the process of diamond lapping and polishing is designed. In such minitype spindle system, the brushless DC spindle motor is used to drive the lapping finish table, which is built with fluid dynamic bearings. Some measures have been taken to make the lapping system dynamic balance, and a servo controller which can adjust the speed of motor from 1 200 r/min to 5 400 r/min is designed. Experiments show that the spindle system is reliable and stable for diamond polishing, and the detection results by atomic force microscope(AFM) show that the surfaces of diamond edge's Ra is 6.725 nm and whole diamond average Ra is 3.25 nm.

  7. Preparation of scanning tunneling microscopy tips using pulsed alternating current etching

    Energy Technology Data Exchange (ETDEWEB)

    Valencia, Victor A.; Thaker, Avesh A.; Derouin, Jonathan; Valencia, Damian N.; Farber, Rachael G.; Gebel, Dana A.; Killelea, Daniel R., E-mail: dkillelea@luc.edu [Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 W. Sheridan Rd., Chicago, Illinois 60660 (United States)

    2015-03-15

    An electrochemical method using pulsed alternating current etching (PACE) to produce atomically sharp scanning tunneling microscopy (STM) tips is presented. An Arduino Uno microcontroller was used to control the number and duration of the alternating current (AC) pulses, allowing for ready optimization of the procedures for both Pt:Ir and W tips using a single apparatus. W tips prepared using constant and pulsed AC power were compared. Tips fashioned using PACE were sharper than those etched with continuous AC power alone. Pt:Ir tips were prepared with an initial coarse etching stage using continuous AC power followed by fine etching using PACE. The number and potential of the finishing AC pulses was varied and scanning electron microscope imaging was used to compare the results. Finally, tip quality using the optimized procedures was verified by UHV-STM imaging. With PACE, at least 70% of the W tips and 80% of the Pt:Ir tips were of sufficiently high quality to obtain atomically resolved images of HOPG or Ni(111)

  8. Regional economic impacts of current and proposed management alternatives for Charles M. Russell National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Ishizaki, Asuka; Ritten, John

    2013-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. Charles M. Russell (CMR) National Wildlife Refuge, located in north-central Montana, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for the Refuge must contain an analysis of expected effects associated with current and proposed refuge-management strategies. For refuge CCP planning, an economic analysis provides a means of estimating how current management (No Action Alternative) and proposed management activities (Alternatives) affect the local economy. This type of analysis provides two critical pieces of information: (1) it illustrates a refuge’s contribution to the local community; and (2) it can help in determining whether economic effects are or are not a real concern in choosing among management alternatives. It is important to note that the economic value of a refuge encompasses more than just the impacts on the regional economy. Refuges also provide substantial nonmarket values (values for items not exchanged in established markets) such as maintaining endangered species, preserving wetlands, educating future generations, and adding stability to the ecosystem (Carver and Caudill, 2007). However, quantifying these types of nonmarket values is beyond the scope of this study. This report first presents a description of the local community and economy near the Refuge. Next, the methods used to conduct a regional economic impact analysis are described. An analysis of the final CCP management strategies that could affect stakeholders and residents and the local economy is then presented. The refuge management activities of economic concern in this analysis are:

  9. Adaptive current compensation with nonlinear disturbance observer for single-sided linear induction motor considering dynamic eddy-effect

    Institute of Scientific and Technical Information of China (English)

    DENG Jiang-ming; CHEN Te-fang; CHEN Chun-yang

    2015-01-01

    An adaptive current compensation control for a single-sided linear induction motor (SLIM) with nonlinear disturbance observer was developed. First, to maintaint-axis secondary component flux constant with consideration of the specially dynamic eddy-effect (DEE) of the SLIM, a instantaneously tracing compensation ofm-axis current component was analyzed. Second, adaptive current compensation based on Taylor-discretization algorithm was proposed. Third, an effective kind of nonlinear disturbance observer (NDOB) was employed to estimate and compensate the undesired load vibrations, then the robustness of the control system could be guaranteed. Experimental verification of the feasibility of the proposed method for an SLIM control system was performed, and it showed that the proposed adaptive compensation scheme with NDOB could significantly promote speed dynamical response and minimize speed ripple under the conditions of external load coupled vibrations and unavoidable feedback control variables measured errors, i.e., current and speed.

  10. Balancing Vibrations at Harmonic Frequencies by Injecting Harmonic Balancing Signals into the Armature of a Linear Motor/Alternator Coupled to a Stirling Machine

    Science.gov (United States)

    Holliday, Ezekiel S. (Inventor)

    2014-01-01

    Vibrations at harmonic frequencies are reduced by injecting harmonic balancing signals into the armature of a linear motor/alternator coupled to a Stirling machine. The vibrations are sensed to provide a signal representing the mechanical vibrations. A harmonic balancing signal is generated for selected harmonics of the operating frequency by processing the sensed vibration signal with adaptive filter algorithms of adaptive filters for each harmonic. Reference inputs for each harmonic are applied to the adaptive filter algorithms at the frequency of the selected harmonic. The harmonic balancing signals for all of the harmonics are summed with a principal control signal. The harmonic balancing signals modify the principal electrical drive voltage and drive the motor/alternator with a drive voltage component in opposition to the vibration at each harmonic.

  11. Alternative (non-animal) methods for cosmetics testing: current status and future prospects-2010.

    Science.gov (United States)

    Adler, Sarah; Basketter, David; Creton, Stuart; Pelkonen, Olavi; van Benthem, Jan; Zuang, Valérie; Andersen, Klaus Ejner; Angers-Loustau, Alexandre; Aptula, Aynur; Bal-Price, Anna; Benfenati, Emilio; Bernauer, Ulrike; Bessems, Jos; Bois, Frederic Y; Boobis, Alan; Brandon, Esther; Bremer, Susanne; Broschard, Thomas; Casati, Silvia; Coecke, Sandra; Corvi, Raffaella; Cronin, Mark; Daston, George; Dekant, Wolfgang; Felter, Susan; Grignard, Elise; Gundert-Remy, Ursula; Heinonen, Tuula; Kimber, Ian; Kleinjans, Jos; Komulainen, Hannu; Kreiling, Reinhard; Kreysa, Joachim; Leite, Sofia Batista; Loizou, George; Maxwell, Gavin; Mazzatorta, Paolo; Munn, Sharon; Pfuhler, Stefan; Phrakonkham, Pascal; Piersma, Aldert; Poth, Albrecht; Prieto, Pilar; Repetto, Guillermo; Rogiers, Vera; Schoeters, Greet; Schwarz, Michael; Serafimova, Rositsa; Tähti, Hanna; Testai, Emanuela; van Delft, Joost; van Loveren, Henk; Vinken, Mathieu; Worth, Andrew; Zaldivar, José-Manuel

    2011-05-01

    The 7th amendment to the EU Cosmetics Directive prohibits to put animal-tested cosmetics on the market in Europe after 2013. In that context, the European Commission invited stakeholder bodies (industry, non-governmental organisations, EU Member States, and the Commission's Scientific Committee on Consumer Safety) to identify scientific experts in five toxicological areas, i.e. toxicokinetics, repeated dose toxicity, carcinogenicity, skin sensitisation, and reproductive toxicity for which the Directive foresees that the 2013 deadline could be further extended in case alternative and validated methods would not be available in time. The selected experts were asked to analyse the status and prospects of alternative methods and to provide a scientifically sound estimate of the time necessary to achieve full replacement of animal testing. In summary, the experts confirmed that it will take at least another 7-9 years for the replacement of the current in vivo animal tests used for the safety assessment of cosmetic ingredients for skin sensitisation. However, the experts were also of the opinion that alternative methods may be able to give hazard information, i.e. to differentiate between sensitisers and non-sensitisers, ahead of 2017. This would, however, not provide the complete picture of what is a safe exposure because the relative potency of a sensitiser would not be known. For toxicokinetics, the timeframe was 5-7 years to develop the models still lacking to predict lung absorption and renal/biliary excretion, and even longer to integrate the methods to fully replace the animal toxicokinetic models. For the systemic toxicological endpoints of repeated dose toxicity, carcinogenicity and reproductive toxicity, the time horizon for full replacement could not be estimated. PMID:21533817

  12. Effects of direct and alternating current on the treatment of oily water in an electroflocculation process

    Directory of Open Access Journals (Sweden)

    A. A. Cerqueira

    2014-09-01

    Full Text Available In the direct current mode (DC, widely used in electroflocculation (EC, the formation of an impermeable oxide layer on the cathode causes the declining of the efficiency of this process. This disadvantage has been reduced by adopting alternating current (AC. In this study, the effects of AC and DC on operational parameters such as the removal of oils and greases (O&G, color and turbidity from oil-in-water (O/W emulsions of the petroleum industry using aluminum electrodes were investigated. Removal efficiencies of 95%, 97% and 99% of O&G, color and turbidity with energy consumption of 0.280 kWh/m³ and electrode consumption of 0.12 g and 0.18 g were achieved at a current density of 3 A, operation time of 3 minutes and initial pH of 9.0 using AC and DC, respectively. In continuous flow tests performed with the same experimental conditions, the electrode consumption at times up to 60 minutes were 1.6 g and 3.4 g using AC and DC, respectively.

  13. Efficacy of lidocaine lontophoresis using either alternating or direct current in hairless rats.

    Science.gov (United States)

    Nakajima, Atsushi; Wakita, Ryo; Haida, Haruka; Fukayama, Haruhisa

    2013-01-01

    The aim of this study was to determine transport of lidocaine ions through a hairless rat skin in vivo and to compare the efficacy of alternating current (AC) with that of direct current (DC) iontophoresis (IOP). We measured the concentration of lidocaine transported through a cellophane membrane or a hairless rat dorsal skin applying either AC-IOP or DC-IOP. The results revealed that lidocaine concentration increased in a time-dependent manner in vitro in both DC-IOP and AC-IOP. However, the in vivo study showed different tendencies in lidocaine concentration. In the DCIOP group, lidocaine concentration reached its maximum 20 min after current application and then decreased rapidly; the AC-IOP group showed an increase in lidocaine concentration in a time-dependent manner. There were no side effects such as electrical burns in the rats. In conclusion, AC can be applied for long periods and DC for short periods, or their application time can be appropriately scheduled. Our study also suggests the mechanism by which voltage waveforms affect the skin when applied by IOP. In the future, these findings will be a solid foundation for developing various kinds of medical equipment such as scheduled drug delivery system that can easily deliver various types of drug. PMID:24146168

  14. OXYGEN BUBBLE DEVELOPMENT ON A PLATINUM ELECTRODE IN BOROSILICATE GLASS MELT BY THE EFFECT OF ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Jiri Matej

    2014-10-01

    or on alternating reduction and re-forming of oxidic layer on the electrode in the transition range, has been suggested. Start of bubble evolution at low alternating current density has also been observed in simple sodium-calcium-silicate glass melt. A relation between bubble release and platinum corrosion caused by reduced silicon has been suggested

  15. Optimal state feedback control of brushless direct-current motor drive systems based on Lyapunov stability criterion

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper develops a unified methodology for a real-time speed control of brushless direct-current motor drive systems in the presence of measurement noise and load torque disturbance. First, the mathematical model and hardware structure of system is established. Next, an optimal state feed back controller using the Kalman filter state estimation technique is derived.This is followed by an adaptive control algorithm to compensate for the effects of noise and disturbance. Those two algorithms working together can provide a very-high-speed regulation and dynamic response over a wide range of operating conditions.Simulated responses are presented to highlight the effectiveness of the proposed control strategy.

  16. Protein kinase Cγ mediates ethanol withdrawal hyper-responsiveness of NMDA receptor currents in spinal cord motor neurons

    OpenAIRE

    Li, Hui-Fang; Mochly-Rosen, Daria; Kendig, Joan J

    2005-01-01

    The present studies were designed to test the hypothesis that neuronal-specific protein kinase Cγ (PKCγ) plays a critical role in acute ethanol withdrawal hyper-responsiveness in spinal cord.Patch-clamp studies were carried out in motor neurons in neonatal rat spinal cord slices. Postsynaptic currents were evoked by brief pulses of 2 mM N-methyl-D-aspartic acid (NMDA) in the presence of bicuculline methiodide 10 μM; strychnine 5 μM and tetrodotoxin 0.5 μM.Both ethanol depression and withdrawa...

  17. Gastric motor dysfunctions in Parkinson's disease: Current pre-clinical evidence.

    Science.gov (United States)

    Pellegrini, Carolina; Antonioli, Luca; Colucci, Rocchina; Ballabeni, Vigilio; Barocelli, Elisabetta; Bernardini, Nunzia; Blandizzi, Corrado; Fornai, Matteo

    2015-12-01

    Parkinson's disease (PD) is associated with several non-motor symptoms, such as behavioral changes, urinary dysfunction, sleep disorders, fatigue and, above all, gastrointestinal (GI) dysfunction, including gastric dysmotility, constipation and anorectal dysfunction. Delayed gastric emptying, progressing to gastroparesis, is reported in up to 100% of patients with PD, and it occurs at all stages of the disease with severe consequences to the patient's quality of life. The presence of α-synuclein (α-syn) aggregates in myenteric neurons throughout the digestive tract, as well as morpho-functional alterations of the enteric nervous system (ENS), have been documented in PD. In particular, gastric dysmotility in PD has been associated with an impairment of the brain-gut axis, involving the efferent fibers of the vagal pathway projecting directly to the gastric myenteric plexus. The present review intends to provide an integrated overview of available knowledge on the possible role played by the ENS, considered as a semi-autonomous nervous network, in the pathophysiology of gastric dysmotility in PD. Particular attention has been paid review how translational evidence in humans and studies in pre-clinical models are allowing a better understanding of the functional, neurochemical and molecular alterations likely underlying gastric motor abnormalities occurring in PD. PMID:26499757

  18. Motor flight without noise and smells. Electric motors as alternative drives for airgliders; Motorflug ohne Laerm und Gestank. Elektromotoren als alternativer Antrieb fuer Segelflugzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Krampitz, I.

    2003-12-01

    While air gliders are noiseless, they have never been independent. Lange Flugzeugbau GmbH are now offering a high-performance air glider with an electric motor, which may open up a new market. (orig.) [German] Lautlos und unabhaengig - bisher passten diese beiden Begriffe bei Segelflugzeugen nicht zusammen. Man war auf Windenfahrer, Schlepppiloten oder auf einen ausklappbaren Verbrennungsmotor angewiesen. Die Lange Flugzeugbau GmbH bietet jetzt ein Hochleistungssegelflugzeug mit Elektromotor an. Es koennte einen neuen Markt erschliessen. (orig.)

  19. Rapid determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration

    Institute of Scientific and Technical Information of China (English)

    XIAO Jun-ping; WANG Xue-feng; ZHOU Qing-xiang; FAN Xiao-yuan; SU Xian-fa; Bai Hua-hua; DUAN Hai-jing

    2007-01-01

    A rapid, simple and sensitive method was demonstrated for the determination of phenolic compounds in water samples by alternating-current oscillopolarographic titration. With the presence of sulfuric acid, phenol could be transferred into a nitroso-compound by reacting with NaNO2. The titration end-point was obtained by the formation of a sharp cut in the oscillopolarographic with infinitesimal NaNO2 on double platinum electrodes. The results showed that phenol had an excellent linear relationship over the range of 4.82×10-6 -9.65×10-3 mol/L, the RSD of the proposed method was lower than 1.5%, and the spiked recoveries of three real water samples were in the range of 95.6%-106.9%.

  20. Novel Alternating Current Electroluminescent Devices with an Asymmetric Structure Based on a Polymer Heterojunction

    Institute of Scientific and Technical Information of China (English)

    谭海曙; 姚建铨; 王昕; 王鹏; 谢洪泉

    2002-01-01

    Novel alternating current electroluminescent devices with an asymmetric structure are successfully fabricated by using a hole-type polymer, poly(2,5-bis (dodecyloxy)-phenylenevinylene) (PDDOPV), and an electron-type polymer, poly(phenyl quinoxaline) (PPQ). The performance of the polymer devices with heteto junctions under ac operation is insensitive to the thickness of the two polymer layers, compared to that under dc operation. This new advantage means easy and cheap production facility on a large scale in the near future. Different emission spectra are obtained when our ac devices are operated in an ac mode, forward or reverse bias. The emission spectrum at reverse bias includes two parts: one from PDDOPV and the other from PPQ.

  1. Alternating current cloud point extraction on a microchip: the effect of electrode geometry.

    Science.gov (United States)

    Sasaki, Naoki; Maekawa, Chisaki; Sato, Kae

    2015-02-01

    We report on the effect of electrode geometry on alternating current cloud point extraction (ACPE). ACPE is a technique utilized to extract membrane-associated biomolecules in an electrode-integrated microfluidic channel. In this study, we investigated the effect of gap size (4∼22 μm) between microband electrodes on ACPE. A decrease in gap size resulted in efficient and rapid concentration of fluorescent-labeled phospholipids, a model of membrane-associated biomolecules. We also investigated the effect of applied voltage amplitude on ACPE using devices with decreased electrode gap size. When the gap was small, ACPE was achieved with low applied voltages. ACPE of membrane proteins extracted from HeLa cells was also studied to demonstrate the applicability of the ACPE to real samples. The results provide a guideline to improve the performance of ACPE and facilitate application of the ACPE technique as part of an overall analytical process.

  2. Alternating Current Dielectrophoresis Optimization of Pt-Decorated Graphene Oxide Nanostructures for Proficient Hydrogen Gas Sensor.

    Science.gov (United States)

    Wang, Jianwei; Rathi, Servin; Singh, Budhi; Lee, Inyeal; Joh, Han-Ik; Kim, Gil-Ho

    2015-07-01

    Alternating current dielectrophoresis (DEP) is an excellent technique to assemble nanoscale materials. For efficient DEP, the optimization of the key parameters like peak-to-peak voltage, applied frequency, and processing time is required for good device. In this work, we have assembled graphene oxide (GO) nanostructures mixed with platinum (Pt) nanoparticles between the micro gap electrodes for a proficient hydrogen gas sensors. The Pt-decorated GO nanostructures were well located between a pair of prepatterned Ti/Au electrodes by controlling the DEP technique with the optimized parameters and subsequently thermally reduced before sensing. The device fabricated using the DEP technique with the optimized parameters showed relatively high sensitivity (∼10%) to 200 ppm hydrogen gas at room temperature. The results indicates that the device could be used in several industry applications, such as gas storage and leak detection. PMID:26042360

  3. TO THE MATTER OF APPRAISAL OF TECHNICAL-ECONOMIC INDICES OF STEEL-MELTING FURNACES OF CONSTANT AND ALTERNATING CURRENT

    Directory of Open Access Journals (Sweden)

    Andrej I. Rozhkov

    2010-01-01

    Full Text Available It is shown that using of static thyristor compensation systems improves efficiency, decreases consumption of power and electrodes, but increases the cost of furnaces of alternating current.

  4. Characterization of antiarrhythmic drugs by alternating current induced arrhythmias in isolated heart tissues.

    Science.gov (United States)

    Borchard, U; Bösken, R; Greeff, K

    1982-04-01

    A new method for inducing arrhythmias or asystolia by the application of a 50 HZ alternating current (ac) to electrically driven heart preparations has been developed and applied to isolated left atria and right ventricular papillary muscles of the guinea-pig. An increase in driving frequency from 1 to 3 HZ effects a significant reduction of the threshold of ac-arrhythmia in guinea-pig papillary muscles but no change in atria. A decrease in temperature from 31 degrees C to 25 degrees C and an increase in [Ca2+]0 from 1.25 to 5 mmol/l elevates threshold for ac-arrhythmia and -asystolia. The fast sodium channel inhibitors quinidine, carticaine and benzylamino-5,6-dihydro-8,9-dimethoxy-imidazo-5,1-a-isoquinoline hydrochloride (HE-36) increase threshold of ac-arrhythmia in left atria and papillary muscles, whereas the slow channel inhibitor verapamil is ineffective in concentrations up to 6 mumol/l. Threshold of ac-arrhythmia is elevated by quinidine predominantly in papillary muscles. Carticaine and HE-36 are effective in left atria and papillary muscles to almost the same extent. Threshold of ac-asystolia is increased mainly in papillary muscles by quinidine and HE-36; carticaine produces a similar increase in left atria and papillary muscles. Verapamil even leads to a decrease in threshold predominantly in papillary muscles. It is concluded that model arrhythmias induced by alternating current are brought about mainly by an increase in Na+-conductance of cardiac cell membranes. The negative chronotropic potency in right atria occurs in the sequence verapamil greater than quinidine greater than carticane approximately HE-36. The negative inotropic potency in papillary muscle occurs in the same sequence but HE-36 increases force of contraction.

  5. Regional economic analysis of current and proposed management alternatives for Rappahannock River Valley National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Sexton, Natalie; Donovan, Ryan

    2009-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan. The Comprehensive Conservation Plan must describe the desired future conditions of a refuge and provide long-range guidance and management direction to achieve refuge purposes. The Rappahannock River Valley National Wildlife Refuge (refuge) is in the process of developing a range of management goals, objectives, and strategies for the Comprehensive Conservation Plan. The Comprehensive Conservation Plan for the refuge must contain an analysis of expected effects associated with current and proposed refuge management strategies. The purpose of this study was to assess the regional economic implications associated with draft Comprehensive Conservation Plan management strategies. Special interest groups and local residents often criticize a change in refuge management, especially if there is a perceived negative impact to the local economy. Having objective data on economic impacts may show that these fears are overstated. Quite often, the extent of economic benefits a refuge provides to a local community is not fully recognized, yet at the same time the effects of negative changes is overstated. Spending associated with refuge recreational activities, such as wildlife viewing and hunting, can generate considerable tourist activity for surrounding communities. Additionally, refuge personnel typically spend considerable amounts of money purchasing supplies in local stores, repairing equipment and purchasing fuel at the local service stations, and reside and spend their salaries in the local community. For refuge Comprehensive Conservation Plan planning, a regional economic assessment provides a means of estimating how current management (no action alternative) and proposed management activities (alternatives) could affect the local economy. This type of analysis provides two critical pieces of

  6. Learned EEG-based regulation of motor-related brain oscillations during application of transcranial electric currents: feasibility and limitations

    Directory of Open Access Journals (Sweden)

    Surjo R Soekadar

    2014-03-01

    Full Text Available Objective: Transcranial direct current stimulation (tDCS improves motor learning and can influence emotional processing or attention. However, it remained unclear whether learned electroencephalography (EEG-based brain-machine interface (BMI control during tDCS is feasible and how application of transcranial electric currents during BMI control would interfere with feature-extraction of physiological brain signals. Here we tested this combination and evaluated stimulation-dependent artifacts across different EEG frequencies and stability of motor imagery-based BMI control. Approach: Ten healthy volunteers were invited to two BMI-sessions, each comprising two 60-trial blocks. During the trials, modulation of mu-rhythms (8-15Hz associated with motor imagery recorded over C4 was translated into online cursor movements on a computer screen. During block 2, either sham (session A or anodal tDCS (session B was applied at 1mA with the stimulation electrode placed 1cm anterior of C4. Main results: tDCS was associated with a significant signal power increase in the lower frequencies most evident in the signal spectrum of the EEG channel closest to the stimulation electrode. Stimulation-dependent signal power increase exhibited a decay of 12dB per decade, leaving frequencies above 9Hz unaffected. Analysis of BMI control performance did not indicate a difference between blocks and tDCS conditions. Conclusion: Application of tDCS during learned EEG-based self-regulation of brain oscillations above 9Hz is feasible and safe, and might improve applicability of BMI systems in patient populations.

  7. Fast Compact Laser Shutter Using a Direct Current Motor and 3D Printing

    CERN Document Server

    Zhang, Grace H; Kawasaki, Akio; Vuletić, Vladan

    2015-01-01

    We present a mechanical laser shutter design that utilizes a DC electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade's range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 $\\pm$ 0.02) m/s with 1 ms activation delay and 10 $\\mu$s jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than $10^8$ cycles.

  8. Desing and Real-Time Analysis of a Direct Current Motor Controller

    Directory of Open Access Journals (Sweden)

    Reinier Torres Labrada

    2011-10-01

    Full Text Available The real time analysis of a DC motor controller is addressed. During the functional analysis, deadline and period of tasks were extracted to be used as parameters for Response Time Analysis (RTA. To get the Worst Case Execution Time (WCET each task is stimulated with a random input vector. A great number of computation time samples were recorded and the WCET computed using the Gumbel statistical distribution. With the WCET, deadlines and periods of the task set under analysis a RTA model is evaluated and its results discussed. By modeling the WCET using the Extreme Values Theory (EVT the need of low level analysis for software and an accurate model for hardware is avoided. The method used here is useful for soft real-time systems and could be applied to other hw/sw platforms easily.

  9. The AC (Alternating Current) Electrical Behavior of Multi-layered Thermoelectric Devices

    Science.gov (United States)

    Alim, Mohammad A.; Budak, Satilmis; Bhattacharjee, Sudip

    2016-08-01

    In this study the ac (alternating current) small-signal electrical data in the frequency range 5 Hz ≤ f ≤ 13 MHz are obtained for the multi-layered thermoelectric (TE) devices to extract underlying operative mechanisms via an equivalent circuit model. This model is developed from the complex plane plots in conjunction with the Bode plot. It is observed that the inductive behavior is prevalent for both unbombarded and bombarded TE devices regardless of the doses as both types are observed as somewhat weak in thermoelectric properties. The bombarded multi-layered devices followed a systematic pattern in ac behavior via semicircular relaxation both in the impedance and admittance planes for the same measured data. This pattern is attributed to the transition from one lumped behavior to two distinct mechanisms. It is observed that the␣conductive nature of the equivalent circuit model via non-blocking (non-capacitive) elements, attributed to the underlying operative electrical paths between the two opposite electrodes across the multi-layered device exists, satisfying direct current conditions of the equivalent circuit model. The inductive behavior at high frequencies originates from the conductive aspect of the lumped response of the device in addition to the contribution of the electrode leads. Thus, the proposed equivalent circuit model contains external inductance that verifies a meaningful representation of the multi-layered TE device, though weak in thermoelectric properties.

  10. The AC (Alternating Current) Electrical Behavior of Multi-layered Thermoelectric Devices

    Science.gov (United States)

    Alim, Mohammad A.; Budak, Satilmis; Bhattacharjee, Sudip

    2016-11-01

    In this study the ac (alternating current) small-signal electrical data in the frequency range 5 Hz ≤ f ≤ 13 MHz are obtained for the multi-layered thermoelectric (TE) devices to extract underlying operative mechanisms via an equivalent circuit model. This model is developed from the complex plane plots in conjunction with the Bode plot. It is observed that the inductive behavior is prevalent for both unbombarded and bombarded TE devices regardless of the doses as both types are observed as somewhat weak in thermoelectric properties. The bombarded multi-layered devices followed a systematic pattern in ac behavior via semicircular relaxation both in the impedance and admittance planes for the same measured data. This pattern is attributed to the transition from one lumped behavior to two distinct mechanisms. It is observed that the conductive nature of the equivalent circuit model via non-blocking (non-capacitive) elements, attributed to the underlying operative electrical paths between the two opposite electrodes across the multi-layered device exists, satisfying direct current conditions of the equivalent circuit model. The inductive behavior at high frequencies originates from the conductive aspect of the lumped response of the device in addition to the contribution of the electrode leads. Thus, the proposed equivalent circuit model contains external inductance that verifies a meaningful representation of the multi-layered TE device, though weak in thermoelectric properties.

  11. Alternating current electrical stimulation enhanced chemotherapy: a novel strategy to bypass multidrug resistance in tumor cells

    Directory of Open Access Journals (Sweden)

    Dini Gabriele

    2006-03-01

    Full Text Available Abstract Background Tumor burden can be pharmacologically controlled by inhibiting cell division and by direct, specific toxicity to the cancerous tissue. Unfortunately, tumors often develop intrinsic pharmacoresistance mediated by specialized drug extrusion mechanisms such as P-glycoprotein. As a consequence, malignant cells may become insensitive to various anti-cancer drugs. Recent studies have shown that low intensity very low frequency electrical stimulation by alternating current (AC reduces the proliferation of different tumor cell lines by a mechanism affecting potassium channels while at intermediate frequencies interfere with cytoskeletal mechanisms of cell division. The aim of the present study is to test the hypothesis that permeability of several MDR1 over-expressing tumor cell lines to the chemotherapic agent doxorubicin is enhanced by low frequency, low intensity AC stimulation. Methods We grew human and rodent cells (C6, HT-1080, H-1299, SKOV-3 and PC-3 which over-expressed MDR1 in 24-well Petri dishes equipped with an array of stainless steel electrodes connected to a computer via a programmable I/O board. We used a dedicated program to generate and monitor the electrical stimulation protocol. Parallel cultures were exposed for 3 hours to increasing concentrations (1, 2, 4, and 8 μM of doxorubicin following stimulation to 50 Hz AC (7.5 μA or MDR1 inhibitor XR9576. Cell viability was assessed by determination of adenylate kinase (AK release. The relationship between MDR1 expression and the intracellular accumulation of doxorubicin as well as the cellular distribution of MDR1 was investigated by computerized image analysis immunohistochemistry and Western blot techniques. Results By the use of a variety of tumor cell lines, we show that low frequency, low intensity AC stimulation enhances chemotherapeutic efficacy. This effect was due to an altered expression of intrinsic cellular drug resistance mechanisms. Immunohistochemical

  12. Alternating Current Stimulation for Vision Restoration after Optic Nerve Damage: A Randomized Clinical Trial

    Science.gov (United States)

    Schittkowski, Michael P.; Antal, Andrea; Ambrus, Géza Gergely; Paulus, Walter; Dannhauer, Moritz; Michalik, Romualda; Mante, Alf; Bola, Michal; Lux, Anke; Kropf, Siegfried; Brandt, Stephan A.; Sabel, Bernhard A.

    2016-01-01

    Background Vision loss after optic neuropathy is considered irreversible. Here, repetitive transorbital alternating current stimulation (rtACS) was applied in partially blind patients with the goal of activating their residual vision. Methods We conducted a multicenter, prospective, randomized, double-blind, sham-controlled trial in an ambulatory setting with daily application of rtACS (n = 45) or sham-stimulation (n = 37) for 50 min for a duration of 10 week days. A volunteer sample of patients with optic nerve damage (mean age 59.1 yrs) was recruited. The primary outcome measure for efficacy was super-threshold visual fields with 48 hrs after the last treatment day and at 2-months follow-up. Secondary outcome measures were near-threshold visual fields, reaction time, visual acuity, and resting-state EEGs to assess changes in brain physiology. Results The rtACS-treated group had a mean improvement in visual field of 24.0% which was significantly greater than after sham-stimulation (2.5%). This improvement persisted for at least 2 months in terms of both within- and between-group comparisons. Secondary analyses revealed improvements of near-threshold visual fields in the central 5° and increased thresholds in static perimetry after rtACS and improved reaction times, but visual acuity did not change compared to shams. Visual field improvement induced by rtACS was associated with EEG power-spectra and coherence alterations in visual cortical networks which are interpreted as signs of neuromodulation. Current flow simulation indicates current in the frontal cortex, eye, and optic nerve and in the subcortical but not in the cortical regions. Conclusion rtACS treatment is a safe and effective means to partially restore vision after optic nerve damage probably by modulating brain plasticity. This class 1 evidence suggests that visual fields can be improved in a clinically meaningful way. Trial Registration ClinicalTrials.gov NCT01280877 PMID:27355577

  13. Characterizing head motor disorders to create novel interfaces for people with cerebral palsy: creating an alternative communication channel by head motion.

    Science.gov (United States)

    Raya, R; Rocon, E; Ceres, R; Harlaar, J; Geytenbeek, J

    2011-01-01

    This paper aims to validate a head mounted inertial interface to characterize disorder movements in people with cerebral palsy (CP). The kinematic patterns extracted from this study will be used to design an alternative communication channel (using head motion) adapted to user's capabilities and limitations. Four people with CP participated (GMFCS level V) and three healthy subjects as reference group. The main outcome measures were divided into 1) Time-domain, 2) Frequency-domain and 3) Spatial domain. Results showed that the inertial interface succeeds assessing the pathological motion. Firstly, the system differentiates between voluntary and involuntary motion in terms of motor control, frequency and range of motion. Secondly some motion disorders such as hypertonia, hypotonia can be identified. These results suggest that people with motor disorders could benefit from the developed inertial system in three fields: 1) diagnosis of motor disorder by means of an objective quantification, 2) physical and cognitive rehabilitation by means of proprioceptive enhancement through visual-motor feedback and 3) functional compensation by means of an inertial person-machine interface for controlling computer and assistive devices (e.g. wheelchairs or walkers). PMID:22275612

  14. Acute changes in motor cortical excitability during slow oscillatory and constant anodal transcranial direct current stimulation

    DEFF Research Database (Denmark)

    Bergmann, Til Ole; Groppa, Sergiu; Seeger, Markus;

    2009-01-01

    Transcranial oscillatory current stimulation has recently emerged as a noninvasive technique that can interact with ongoing endogenous rhythms of the human brain. Yet, there is still little knowledge on how time-varied exogenous currents acutely modulate cortical excitability. In ten healthy...

  15. Construction of AC Motor Controllers for NOvA Experiment Upgrades

    CERN Document Server

    Cooley, Patrick

    2012-01-01

    I have been constructing Alternating Current (AC) motor controllers for manipulation of particle beam detectors. The capability and reliability of these motor controllers are essential to the Laboratory's mission of accurate analysis of the particle beam's position. The device is moved in and out of the beam's path by the motor controller followed by the Neutrinos at the Main Injector Off-Axis {\

  16. Transcranial alternating current stimulation increases risk-taking behavior in the balloon analog risk task.

    Science.gov (United States)

    Sela, Tal; Kilim, Adi; Lavidor, Michal

    2012-01-01

    The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC). It has been proposed that in conflict and reward situations, theta-band (4-8 Hz) oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere (RH), is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial alternating current stimulation, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation/RH stimulation/Sham stimulation), with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1 mA peak-to-peak). During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations. PMID:22347844

  17. DC bias effect on alternating current electrical conductivity of poly(ethylene terephthalate)/alumina nanocomposites

    Science.gov (United States)

    Nikam, Pravin N.; Deshpande, Vineeta D.

    2016-05-01

    Polymer nanocomposites based on metal oxide (ceramic) nanoparticles are a new class of materials with unique properties and designed for various applications such as electronic device packaging, insulation, fabrication and automotive industries. Poly(ethylene terephthalate) (PET)/alumina (Al2O3) nanocomposites with filler content between 1 wt% and 5 wt% were prepared by melt compounding method using co-rotating twin screw extruder and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and precision LCR meter techniques. The results revealed that proper uniform dispersion at lower content up to 2 wt% of nano-alumina observed by using TEM. Aggregation of nanoparticles was observed at higher content of alumina examined by using SEM and TEM. The frequency dependences of the alternating current (AC) conductivity (σAC) of PET/alumina nanocomposites on the filler content and DC bias were investigated in the frequency range of 20Hz - 1MHz. The results showed that the AC and direct current (DC) conductivity increases with increasing DC bias and nano-alumina content upto 3 wt%. It follows the Jonscher's universal power law of solids. It revealed that σAC of PET/alumina nanocomposites can be well characterized by the DC conductivity (σDC), critical frequency (ωc), critical exponent of the power law (s). Roll of DC bias potential led to an increase of DC conductivity (σDC) due to the creation of additional conducting paths with the polymer nanocomposites and percolation behavior achieved through co-continuous morphology.

  18. Alternating current electrohydrodynamics in microsystems: Pushing biomolecules and cells around on surfaces.

    Science.gov (United States)

    Vaidyanathan, Ramanathan; Dey, Shuvashis; Carrascosa, Laura G; Shiddiky, Muhammad J A; Trau, Matt

    2015-11-01

    Electrohydrodynamics (EHD) deals with the fluid motion induced by an electric field. This phenomenon originally developed in physical science, and engineering is currently experiencing a renaissance in microfluidics. Investigations by Taylor on Gilbert's theory proposed in 1600 have evolved to include multiple contributions including the promising effects arising from electric field interactions with cells and particles to influence their behaviour on electrode surfaces. Theoretical modelling of electric fields in microsystems and the ability to determine shear forces have certainly reached an advanced state. The ability to deftly manipulate microscopic fluid flow in bulk fluid and at solid/liquid interfaces has enabled the controlled assembly, coagulation, or removal of microstructures, nanostructures, cells, and molecules on surfaces. Furthermore, the ability of electrohydrodynamics to generate fluid flow using surface shear forces generated within nanometers from the surface and their application in bioassays has led to recent advancements in biomolecule, vesicle and cellular detection across different length scales. With the integration of Alternating Current Electrohydrodynamics (AC-EHD) in cellular and molecular assays proving to be highly fruitful, challenges still remain with respect to understanding the discrepancies between each of the associated ac-induced fluid flow phenomena, extending their utility towards clinical diagnostic development, and utilising them in tandem as a standard tool for disease monitoring. In this regard, this article will review the history of electrohydrodynamics, followed by some of the recent developments in the field including a new dimension of electrohydrodynamics that deals with the utilization of surface shear forces for the manipulation of biological cells or molecules on electrode surfaces. Recent advances and challenges in the use of electrohydrodynamic forces such as dielectrophoresis and ac electrosmosis for the

  19. From amusic to musical?--Improving pitch memory in congenital amusia with transcranial alternating current stimulation.

    Science.gov (United States)

    Schaal, Nora K; Pfeifer, Jasmin; Krause, Vanessa; Pollok, Bettina

    2015-11-01

    Brain imaging studies highlighted structural differences in congenital amusia, a life-long perceptual disorder that is associated with pitch perception and pitch memory deficits. A functional anomaly characterized by decreased low gamma oscillations (30-40 Hz range) in the right dorsolateral prefrontal cortex (DLPFC) during pitch memory has been revealed recently. Thus, the present study investigates whether applying transcranial alternating current stimulation (tACS) at 35 Hz to the right DLPFC would improve pitch memory. Nine amusics took part in two tACS sessions (either 35 Hz or 90 Hz) and completed a pitch and visual memory task before and during stimulation. 35 Hz stimulation facilitated pitch memory significantly. No modulation effects were found with 90 Hz stimulation or on the visual task. While amusics showed a selective impairment of pitch memory before stimulation, the performance during 35 Hz stimulation was not significantly different to healthy controls anymore. Taken together, the study shows that modulating the right DLPFC with 35 Hz tACS in congenital amusia selectively improves pitch memory performance supporting the hypothesis that decreased gamma oscillations within the DLPFC are causally involved in disturbed pitch memory and highlight the potential use of tACS to interact with cognitive processes. PMID:26254878

  20. Atmospheric pressure chemical ionization of explosives using alternating current corona discharge ion source.

    Science.gov (United States)

    Usmanov, D T; Chen, L C; Yu, Z; Yamabe, S; Sakaki, S; Hiraoka, K

    2015-04-01

    The high-sensitive detection of explosives is of great importance for social security and safety. In this work, the ion source for atmospheric pressure chemical ionization/mass spectrometry using alternating current corona discharge was newly designed for the analysis of explosives. An electromolded fine capillary with 115 µm inner diameter and 12 mm long was used for the inlet of the mass spectrometer. The flow rate of air through this capillary was 41 ml/min. Stable corona discharge could be maintained with the position of the discharge needle tip as close as 1 mm to the inlet capillary without causing the arc discharge. Explosives dissolved in 0.5 µl methanol were injected to the ion source. The limits of detection for five explosives with 50 pg or lower were achieved. In the ion/molecule reactions of trinitrotoluene (TNT), the discharge products of NOx (-) (x = 2,3), O3 and HNO3 originating from plasma-excited air were suggested to contribute to the formation of [TNT - H](-) (m/z 226), [TNT - NO](-) (m/z 197) and [TNT - NO + HNO3 ](-) (m/z 260), respectively. Formation processes of these ions were traced by density functional theory calculations. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26149109

  1. Friends, not foes: Magnetoencephalography as a tool to uncover brain dynamics during transcranial alternating current stimulation.

    Science.gov (United States)

    Neuling, Toralf; Ruhnau, Philipp; Fuscà, Marco; Demarchi, Gianpaolo; Herrmann, Christoph S; Weisz, Nathan

    2015-09-01

    Brain oscillations are supposedly crucial for normal cognitive functioning and alterations are associated with cognitive dysfunctions. To demonstrate their causal role on behavior, entrainment approaches in particular aim at driving endogenous oscillations via rhythmic stimulation. Within this context, transcranial electrical stimulation, especially transcranial alternating current stimulation (tACS), has received renewed attention. This is likely due to the possibility of defining oscillatory stimulation properties precisely. Also, measurements comparing pre-tACS with post-tACS electroencephalography (EEG) have shown impressive modulations. However, the period during tACS has remained a blackbox until now, due to the enormous stimulation artifact. By means of application of beamforming to magnetoencephalography (MEG) data, we successfully recovered modulations of the amplitude of brain oscillations during weak and strong tACS. Additionally, we demonstrate that also evoked responses to visual and auditory stimuli can be recovered during tACS. The main contribution of the present study is to provide critical evidence that during ongoing tACS, subtle modulations of oscillatory brain activity can be reconstructed even at the stimulation frequency. Future tACS experiments will be able to deliver direct physiological insights in order to further the understanding of the contribution of brain oscillations to cognition and behavior.

  2. Bead-on-string structure printed by electrohydrodynamic jet under alternating current electric field

    Science.gov (United States)

    Liu, Juan; Lin, Yihuang; Jiang, Jiaxin; Liu, Haiyan; Zhao, Yang; Zheng, Gaofeng

    2016-09-01

    Electrohydrodynamic printing (EHDP) under alternating current (AC) electric field provides a novel way for the precise micro-/nano-droplet printing. The AC electric field induces the free charge to reciprocate along the EHDP jet and changes the electric field force on the jet periodically. The stability of jet can be enhanced by increasing the voltage frequency, and the regular bead-on-string structure is direct-written along the trajectory of collector. The deposition frequency of bead structure increases with the increasing of voltage frequency, due to the short period of AC electric field. As the voltage frequency is increased from 10 to 60 Hz, the diameter of bead structure decreases from 200 to 110 µm. As the duty ration increased from 10 to 60 %, the diameter of bead structure increased from 100 to 140 µm. This work would accelerate the development and the application of micro-/nano-printing technology in the fields of flexible electronic and micro-/nano-system.

  3. From amusic to musical?--Improving pitch memory in congenital amusia with transcranial alternating current stimulation.

    Science.gov (United States)

    Schaal, Nora K; Pfeifer, Jasmin; Krause, Vanessa; Pollok, Bettina

    2015-11-01

    Brain imaging studies highlighted structural differences in congenital amusia, a life-long perceptual disorder that is associated with pitch perception and pitch memory deficits. A functional anomaly characterized by decreased low gamma oscillations (30-40 Hz range) in the right dorsolateral prefrontal cortex (DLPFC) during pitch memory has been revealed recently. Thus, the present study investigates whether applying transcranial alternating current stimulation (tACS) at 35 Hz to the right DLPFC would improve pitch memory. Nine amusics took part in two tACS sessions (either 35 Hz or 90 Hz) and completed a pitch and visual memory task before and during stimulation. 35 Hz stimulation facilitated pitch memory significantly. No modulation effects were found with 90 Hz stimulation or on the visual task. While amusics showed a selective impairment of pitch memory before stimulation, the performance during 35 Hz stimulation was not significantly different to healthy controls anymore. Taken together, the study shows that modulating the right DLPFC with 35 Hz tACS in congenital amusia selectively improves pitch memory performance supporting the hypothesis that decreased gamma oscillations within the DLPFC are causally involved in disturbed pitch memory and highlight the potential use of tACS to interact with cognitive processes.

  4. Alternating current cloud point extraction on a microchip: a comprehensive study.

    Science.gov (United States)

    Sasaki, Naoki; Takemura, Azusa; Sato, Kae

    2012-11-01

    We present a comprehensive study of alternating current cloud point extraction (ACPE) on a microchip. ACPE is an extraction technique for preconcentration of membrane-associated biomolecules. To characterize and optimize ACPE, we carried out ACPE experiments under various experimental conditions including amplitude and frequency of applied voltages, flow velocity, and concentration of surfactant, analyte, and salt. We found that ACPE has an amplitude threshold (15 V(p-p)), above which the extraction was more efficient. The dependence of the extraction on frequency (>5 MHz) was insignificant. Efficient extraction was achieved when the velocity of the test solution was 0.10∼0.67 mm s⁻¹ and the concentration of surfactant was 0.10∼1.0%. In contrast, the extraction was independent of the concentration of analytes (0.20∼20 μmol dm⁻³). The technique was applicable to solutions with a salt concentration of 0.050∼0.15 mol dm⁻³ under temperature control of the devices. Solution temperature in ACPE was also studied. These results provide guidelines for use of the ACPE technique in microfluidic chemical and biochemical analyses.

  5. Two interconnected kernels of reciprocally inhibitory interneurons underlie alternating left-right swim motor pattern generation in the mollusk Melibe leonina.

    Science.gov (United States)

    Sakurai, Akira; Gunaratne, Charuni A; Katz, Paul S

    2014-09-15

    The central pattern generator (CPG) underlying the rhythmic swimming behavior of the nudibranch Melibe leonina (Mollusca, Gastropoda, Heterobranchia) has been described as a simple half-center oscillator consisting of two reciprocally inhibitory pairs of interneurons called swim interneuron 1 (Si1) and swim interneuron 2 (Si2). In this study, we identified two additional pairs of interneurons that are part of the swim CPG: swim interneuron 3 (Si3) and swim interneuron 4 (Si4). The somata of Si3 and Si4 were both located in the pedal ganglion, near that of Si2, and both had axons that projected through the pedal commissure to the contralateral pedal ganglion. These neurons fulfilled the criteria for inclusion as members of the swim CPG: 1) they fired at a fixed phase in relation to Si1 and Si2, 2) brief changes in their activity reset the motor pattern, 3) prolonged changes in their activity altered the periodicity of the motor pattern, 4) they had monosynaptic connections with each other and with Si1 and Si2, and 5) their synaptic actions helped explain the phasing of the motor pattern. The results of this study show that the motor pattern has more complex internal dynamics than a simple left/right alternation of firing; the CPG circuit appears to be composed of two kernels of reciprocally inhibitory neurons, one consisting of Si1, Si2, and the contralateral Si4 and the other consisting of Si3. These two kernels interact with each other to produce a stable rhythmic motor pattern.

  6. 75 FR 41521 - Delphi Corporation, Automotive Holding Group, Plant 6, Currently Known as General Motors...

    Science.gov (United States)

    2010-07-16

    ... determination was published in the Federal Register on October 17, 2007 (72 FR 58899). The certification was... on March 3, 2009 (74 FR 9287). At the request of the State agency, the Department reviewed the... Employment and Training Administration Delphi Corporation, Automotive Holding Group, Plant 6, Currently...

  7. Catecholaminergic Fiber Innervation of the Vocal Motor System Is Intrasexually Dimorphic in a Teleost with Alternative Reproductive Tactics.

    Science.gov (United States)

    Ghahramani, Zachary N; Timothy, Miky; Kaur, Gurpreet; Gorbonosov, Michelle; Chernenko, Alena; Forlano, Paul M

    2015-01-01

    Catecholamines, which include the neurotransmitters dopamine and noradrenaline, are known modulators of sensorimotor function, reproduction, and sexually motivated behaviors across vertebrates, including vocal-acoustic communication. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the vocal motor system in the plainfin midshipman fish Porichthys notatus, a seasonal breeding marine teleost that produces vocal signals for social communication. There are 2 distinct male reproductive morphs in this species: type I males establish nests and court females with a long-duration advertisement call, while type II males sneak spawn to steal fertilizations from type I males. Like females, type II males can only produce brief, agonistic, grunt type vocalizations. Here, we tested the hypothesis that intrasexual differences in the number of CA neurons and their fiber innervation patterns throughout the vocal motor pathway may provide neural substrates underlying divergence in reproductive behavior between morphs. We employed immunofluorescence (-ir) histochemistry to measure tyrosine hydroxylase (TH; a rate-limiting enzyme in catecholamine synthesis) neuron numbers in several forebrain and hindbrain nuclei as well as TH-ir fiber innervation throughout the vocal pathway in type I and type II males collected from nests during the summer reproductive season. After controlling for differences in body size, only one group of CA neurons displayed an unequivocal difference between male morphs: the extraventricular vagal-associated TH-ir neurons, located just lateral to the dimorphic vocal motor nucleus (VMN), were significantly greater in number in type II males. In addition, type II males exhibited greater TH-ir fiber density within the VMN and greater numbers of TH-ir varicosities with putative contacts on vocal motor neurons. This strong inverse relationship between the predominant vocal morphotype and the CA innervation of vocal motor neurons suggests

  8. Catecholaminergic fiber innervation of the vocal motor system is intrasexually dimorphic in a teleost with alternative reproductive tactics

    Science.gov (United States)

    Ghahramani, Zachary N.; Timothy, Miky; Kaur, Gurpreet; Gorbonosov, Michelle; Chernenko, Alena; Forlano, Paul M.

    2015-01-01

    Catecholamines, which include the neurotransmitters dopamine and noradrenaline, are known modulators of sensorimotor function, reproduction, and sexually motivated behaviors across vertebrates, including vocal-acoustic communication. Recently, we demonstrated robust catecholaminergic (CA) innervation throughout the vocal-motor system in the plainfin midshipman fish, Porichtys notatus, a seasonal breeding marine teleost that produces vocal signals for social communication. There are two distinct male reproductive morphs in this species: Type I males establish nests and court females with a long duration advertisement call, while type II males sneak-spawn to steal fertilizations from type I males. Like females, type II males can only produce brief, agonistic, grunt-type vocalizations. Here, we tested the hypothesis that intrasexual differences in the numbers of CA neurons and their fiber innervation patterns throughout the vocal-motor pathway may provide neural substrates underlying divergence in reproductive behavior between morphs. We employed immunofluorescence (-ir) histochemistry to measure tyrosine hydroxylase (TH, rate-limiting enzyme in catecholamine synthesis) neuron numbers in several forebrain and hindbrain nuclei as well as TH-ir fiber innervation throughout the vocal pathway in type I and type II males collected from nests during the summer reproductive season. After controlling for differences in body size, only one group of CA neurons displayed an unequivocal difference between male morphs: the extraventricular vagal-associated TH-ir neurons, located just lateral to the dimorphic vocal motor nucleus (VMN), were significantly greater in number in type II males. In addition, type II males exhibited greater TH-ir fiber density within the VMN and greater numbers of TH-ir varicosities with putative contacts on vocal motor neurons. This strong inverse relationship between the predominant vocal morphotype and CA innervation of vocal motor neurons suggests

  9. Concurrent Electroencephalography Recording During Transcranial Alternating Current Stimulation (tACS).

    Science.gov (United States)

    Fehér, Kristoffer D; Morishima, Yosuke

    2016-01-01

    Oscillatory brain activities are considered to reflect the basis of rhythmic changes in transmission efficacy across brain networks and are assumed to integrate cognitive neural processes. Transcranial alternating current stimulation (tACS) holds the promise to elucidate the causal link between specific frequencies of oscillatory brain activity and cognitive processes. Simultaneous electroencephalography (EEG) recording during tACS would offer an opportunity to directly explore immediate neurophysiological effects of tACS. However, it is not trivial to measure EEG signals during tACS, as tACS creates a huge artifact in EEG data. Here we explain how to set up concurrent tACS-EEG experiments. Two necessary considerations for successful EEG recording while applying tACS are highlighted. First, bridging of the tACS and EEG electrodes via leaking EEG gel immediately saturates the EEG amplifier. To avoid bridging via gel, the viscosity of the EEG gel is the most important parameter. The EEG gel must be viscous to avoid bridging, but at the same time sufficiently fluid to create contact between the tACS electrode and the scalp. Second, due to the large amplitude of the tACS artifact, it is important to consider using an EEG system with a high resolution analog-to-digital (A/D) converter. In particular, the magnitude of the tACS artifact can exceed 100 mV at the vicinity of a stimulation electrode when 1 mA tACS is applied. The resolution of the A/D converter is of importance to measure good quality EEG data from the vicinity of the stimulation site. By following these guidelines for the procedures and technical considerations, successful concurrent EEG recording during tACS will be realized. PMID:26862814

  10. Bat algorithm optimized fuzzy PD based speed controller for brushless direct current motor

    Directory of Open Access Journals (Sweden)

    K. Premkumar

    2016-06-01

    Full Text Available In this paper, design of fuzzy proportional derivative controller and fuzzy proportional derivative integral controller for speed control of brushless direct current drive has been presented. Optimization of the above controllers design is carried out using nature inspired optimization algorithms such as particle swarm, cuckoo search, and bat algorithms. Time domain specifications such as overshoot, undershoot, settling time, recovery time, and steady state error and performance indices such as root mean squared error, integral of absolute error, integral of time multiplied absolute error and integral of squared error are measured and compared for the above controllers under different operating conditions such as varying set speed and load disturbance conditions. The precise investigation through simulation is performed using simulink toolbox. From the simulation test results, it is evident that bat optimized fuzzy proportional derivative controller has superior performance than the other controllers considered. Experimental test results have also been taken and analyzed for the optimal controller identified through simulation.

  11. Evaluation of Motor Neuron Excitability by CMAP Scanning with Electric Modulated Current

    Science.gov (United States)

    Araújo, Tiago; Candeias, Rui; Nunes, Neuza; Gamboa, Hugo

    2015-01-01

    Introduction. Compound Muscle Action Potential (CMAP) scan is a noninvasive promissory technique for neurodegenerative pathologies diagnosis. In this work new CMAP scan protocols were implemented to study the influence of electrical pulse waveform on peripheral nerve excitability. Methods. A total of 13 healthy subjects were tested. Stimulation was performed with an increasing intensities range from 4 to 30 mA. The procedure was repeated 4 times per subject, using a different single pulse stimulation waveform: monophasic square and triangular and quadratic and biphasic square. Results. Different waveforms elicit different intensity-response amplitude curves. The square pulse needs less current to generate the same response amplitude regarding the other waves and this effect is gradually decreasing for the triangular, quadratic, and biphasic pulse, respectively. Conclusion. The stimulation waveform has a direct influence on the stimulus-response slope and consequently on the motoneurons excitability. This can be a new prognostic parameter for neurodegenerative disorders. PMID:26413499

  12. Evaluation of Motor Neuron Excitability by CMAP Scanning with Electric Modulated Current

    Directory of Open Access Journals (Sweden)

    Tiago Araújo

    2015-01-01

    Full Text Available Introduction. Compound Muscle Action Potential (CMAP scan is a noninvasive promissory technique for neurodegenerative pathologies diagnosis. In this work new CMAP scan protocols were implemented to study the influence of electrical pulse waveform on peripheral nerve excitability. Methods. A total of 13 healthy subjects were tested. Stimulation was performed with an increasing intensities range from 4 to 30 mA. The procedure was repeated 4 times per subject, using a different single pulse stimulation waveform: monophasic square and triangular and quadratic and biphasic square. Results. Different waveforms elicit different intensity-response amplitude curves. The square pulse needs less current to generate the same response amplitude regarding the other waves and this effect is gradually decreasing for the triangular, quadratic, and biphasic pulse, respectively. Conclusion. The stimulation waveform has a direct influence on the stimulus-response slope and consequently on the motoneurons excitability. This can be a new prognostic parameter for neurodegenerative disorders.

  13. Evaluation of Motor Neuron Excitability by CMAP Scanning with Electric Modulated Current.

    Science.gov (United States)

    Araújo, Tiago; Candeias, Rui; Nunes, Neuza; Gamboa, Hugo

    2015-01-01

    Introduction. Compound Muscle Action Potential (CMAP) scan is a noninvasive promissory technique for neurodegenerative pathologies diagnosis. In this work new CMAP scan protocols were implemented to study the influence of electrical pulse waveform on peripheral nerve excitability. Methods. A total of 13 healthy subjects were tested. Stimulation was performed with an increasing intensities range from 4 to 30 mA. The procedure was repeated 4 times per subject, using a different single pulse stimulation waveform: monophasic square and triangular and quadratic and biphasic square. Results. Different waveforms elicit different intensity-response amplitude curves. The square pulse needs less current to generate the same response amplitude regarding the other waves and this effect is gradually decreasing for the triangular, quadratic, and biphasic pulse, respectively. Conclusion. The stimulation waveform has a direct influence on the stimulus-response slope and consequently on the motoneurons excitability. This can be a new prognostic parameter for neurodegenerative disorders. PMID:26413499

  14. Influence of a Transverse Electric Field on the Alternating Currents Rectification Effect in Superstructures with Non-additive Energy Spectrum

    Directory of Open Access Journals (Sweden)

    V.I. Konchenkov

    2015-12-01

    Full Text Available It is investigated the effect of mutual rectification of alternating currents, induced by an electric field of two uniformly polarized electromagnetic waves with different frequencies in two-dimensional superlattice with non-additive energy spectrum under the influence of a constant transverse electric field. The possibility of control of constant component of electric current (amplification, change of sign, suppression by the transverse electric field is shown. The abilities of the practical use of the results are discussed.

  15. Alternating current thin film electroluminescence in the near infrared from zinc sulfide doped with rare earths

    Science.gov (United States)

    Kale, Ajay

    Near infrared emission (0.7--1.5 mum) of zinc sulfide (ZnS) doped with erbium (Er) or neodymium (Nd) has been studied in alternating current thin film electroluminescent devices (ACTFELDs). The electroluminescent (EL) thin film phosphors were radio frequency planar magnetron sputter deposited by co-sputtering an undoped ZnS target together with a ZnS: 1.5 mole% ErF 3 or ZnS: 1.5 mole% NdF3 target. The ZnS:ErF3 and ZnS:NdF3 thin film phosphors were annealed for one hour in ultra high purity N2 at temperatures ranging from 350--475°C. Annealing at 425°C for 1 hour in nitrogen was the optimal post-deposition treatment for both the ZnS:ErF3, and ZnS:NdF3 thin film phosphors, resulting in EL power densities of 7.5 and 28 muW/cm2 for the 990nm and the 1550nm emission of ZnS:ErF3, respectively. The power densities were 7.5 (750%) and 28 (2800%) times larger than those from the as-deposited films, which exhibited a power density ˜1muW/cm 2 at both wavelengths. In the case of ZnS:NdF3, 26 and 15 muW/cm2 deposited samples. Post-deposition annealing resulted in a 8 and 1.5 times increase in total device efficiency to 0.42 W/W and 0.7 W/W) for ZnS:ErF3 and ZnS:NdF3, respectively. This was attributed to a reduction in the concentration of shallow defects, which leads to a larger effective phosphor field and band bending, an increase in the conduction charge, and a reduction of inelastic scattering of ballistic electrons. While the peak emission wavelengths from Er were independent of annealing temperature, peak shifts were observed for Nd due to hybridization of the 5d-4f orbitals. At annealing temperatures 425°C, the shallow defect states are annealed out, leading to more efficient direct radiative relaxation from the higher lying excited states, and more intense visible luminescence is observed.

  16. Alternating current impedance spectroscopic analysis of biofunctionalized vertically-aligned silica nanospring surface for biosensor applications

    Science.gov (United States)

    Timalsina, Yukta P.

    In this dissertation, a process of vertically-aligned (silica) nanosprings (VANS) based biosensor development is presented. Alternating current (AC) impedance spectroscopy has been used to analyze sensor response as a function of saline phosphate (SP) buffer and biological solutions. The sensor is a parallel plate capacitor consisting of two glass substrates coated with indium tin oxide (ITO), where the VANS [or randomly-aligned nanosprings (RANS)] grown on one substrate serve as the dielectric spacer layer. The response of a VANS device as a function of ionic concentration in SP buffer was examined and an equivalent circuit model was developed. The results demonstrated that VANS sensors exhibited greater sensitivity to the changes in SP concentration relative to the ITO sensors, which serve as controls. The biofunctionalized VANS surface via physisorption and the cross-linker method demonstrates the repeatability, specificity, and selectivity of the binding. The physisorption of biotinylated immunoglobulin G (B-IgG) onto the VANS surface simplifies the whole sensing procedure for the detection of glucose oxidase, since the avidin-conjugated glucose oxidase (Av-GOx) can directly be immobilized on the B-IgG. The cross linker method involves the covalent attachment of antibodies onto the functionalized VANS surface via imine bond. The experiments revealed that the VANS sensor response is solely the result of the interaction of target molecule i.e. mouse IgG with the probe layer, i.e. goat antimouse IgG (GalphaM IgG). It was determined that VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls above 100 Hz, which indicates that the addition of biomolecules inhibits the diffusion of ions and changes the effective dielectric response of the VANS via biomolecular polarization. The study of ionic transport in nanosprings suggested that conductance follows a scaling law. It was demonstrated that a VANS-based device

  17. Characterization of an electrochemical mercury sensor using alternating current, cyclic, square wave and differential pulse voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Guerreiro, Gabriela V.; Zaitouna, Anita J.; Lai, Rebecca Y., E-mail: rlai2@unl.edu

    2014-01-31

    Graphical abstract: -- Highlights: •An electrochemical Hg(II) sensor based on T–Hg(II)–T sensing motif was fabricated. •A methylene blue-modified DNA probe was used to fabricate the sensor. •Sensor performance was evaluated using ACV, CV, SWV, and DPV. •The sensor behaves as a “signal-off” sensor in ACV and CV. •The sensor behaves as either a “signal-on” or “signal-off” sensor in SWV and DPV. -- Abstract: Here we report the characterization of an electrochemical mercury (Hg{sup 2+}) sensor constructed with a methylene blue (MB)-modified and thymine-containing linear DNA probe. Similar to the linear probe electrochemical DNA sensor, the resultant sensor behaved as a “signal-off” sensor in alternating current voltammetry and cyclic voltammetry. However, depending on the applied frequency or pulse width, the sensor can behave as either a “signal-off” or “signal-on” sensor in square wave voltammetry (SWV) and differential pulse voltammetry (DPV). In SWV, the sensor showed “signal-on” behavior at low frequencies and “signal-off” behavior at high frequencies. In DPV, the sensor showed “signal-off” behavior at short pulse widths and “signal-on” behavior at long pulse widths. Independent of the sensor interrogation technique, the limit of detection was found to be 10 nM, with a linear dynamic range between 10 nM and 500 nM. In addition, the sensor responded to Hg{sup 2+} rather rapidly; majority of the signal change occurred in <20 min. Overall, the sensor retains all the characteristics of this class of sensors; it is reagentless, reusable, sensitive, specific and selective. This study also highlights the feasibility of using a MB-modified probe for real-time sensing of Hg{sup 2+}, which has not been previously reported. More importantly, the observed “switching” behavior in SWV and DPV is potentially generalizable and should be applicable to most sensors in this class of dynamics-based electrochemical biosensors.

  18. Optimization of total harmonic current distortion and torque pulsation reduction in high-power induction motors using genetic algorithms

    Institute of Scientific and Technical Information of China (English)

    Arash SAYYAH; Mitra AFLAK; Alireza REZAZADEH

    2008-01-01

    This paper presents a powerful application of genetic algorithm (GA) for the minimization of the total harmonic current distortion (THCD) in high-power induction motors fed by voltage source inverters,based on an approximate harmonic model. That is,having defined a desired fundamental output voltage,optimal pulse patterns (switching angles) are determined to produce the fundamental output voltage while minimizing the THCD. The complete results for the two cases of three and five switching instants in the first quarter period of pulse width modulation (PWM) waveform are presented. Presence of harmonics in the stator excitation leads to a pulsing-torque component. Considering the fact that if the pulsing-torques are at low frequencies,they can cause troublesome speed fluctuations,shaft fatigue,and unsatisfactory performance in the feedback control system,the 5th,7th,11 th,and 13th current harmonics (in the case of five switching angles) are con strained at some pre-specified values,to mitigate the detrimental effects of low-frequency harmonics. At the same time,the THCD is optimized while the required fun-damental output voltage is maintained.

  19. COMPARISON THE EFFECT OF SIMULTANEOUS SENSORY STIMULATION AND CURRENT OCCUPATIONAL THERAPY APPROACHES ON MOTOR DEVELOPMENT OF THE INFANTS WITH DOWN SYNDROME

    Directory of Open Access Journals (Sweden)

    Hossein KARIMI

    2010-12-01

    Full Text Available ObjectiveNeuromuscular characteristics in Down syndrome result in generalized muscular hypotonia, developmental delays and sensory integration deficits. The aim of this study was to compare the effects of simultaneous sensory stimulations and current occupational therapy approaches on motor functions development of infants with Down syndrome.Materials & MethodsEighteen infants with Down syndrome, aged 6 -18 months, were evaluated in two groups: intervention group (simultaneous sensory stimulation and occupational therapy and control group (occupational therapy alone. They attended the program 3 times a week for 6 months and each session lasted 45 minutes. Motor functions were assessed before, during, and after intervention in the two groups, using GMFM test.ResultsMean motor function increased in both groups according to the GMFM test (P = 0.000. Comparison of the changes showed that although the mean difference of this variable was higher in the intervention group, the difference was not statistically significant (P = 0.576.Mean motor deficit reduced in both groups during the period of the study,which was statistically significant (P ConclusionEarly use of simultaneous sensory stimulations can improve the quality of motor skills in Down syndrome infants. It is suggested that it may be used as an early intervention in association with other methods in the rehabilitation of these patients. However, more studies in this regard are warranted.Keywords:Down syndrome, Motor development, Occupational therapy, Sensory stimulation.

  20. EVALUATION OF CURRENTLY AVAILABLE ALTERNATIVES TO METHYL BROMIDE FOR ORNAMENTAL CROP PRODUCTION IN FLORIDA

    Science.gov (United States)

    Studies were designed to test the efficacy of the chemical alternatives, Midas™ (iodomethane:chloropicrin (pic) 50:50 [MI 50:50] and 98:2 [MI 98:2], Arysta LifeScience Corp., Cary, NC) and dimethyl disulfide:pic (Paladin™ 79:21 [DMDS], United Phosphorous, Inc., King of Prussia, PA) compared with met...

  1. Sustained diffusive alternating current gliding arc discharge in atmospheric pressure air

    DEFF Research Database (Denmark)

    Zhu, Jiajian; Gao, Jinlong; Li, Zhongshan;

    2014-01-01

    Rapid transition from glow discharge to thermal arc has been a common problem in generating stable high-power non-thermal plasmas especially at ambient conditions. A sustained diffusive gliding arc discharge was generated in a large volume in atmospheric pressure air, driven by an alternating...

  2. Complementary and Alternative Medicine in Rural Communities: Current Research and Future Directions

    Science.gov (United States)

    Wardle, Jon; Lui, Chi-Wai; Adams, Jon

    2012-01-01

    Contexts: The consumption of complementary and alternative medicine (CAM) in rural areas is a significant contemporary health care issue. An understanding of CAM use in rural health can provide a new perspective on health beliefs and practice as well as on some of the core service delivery issues facing rural health care generally. Purpose: This…

  3. Slow-oscillatory transcranial direct current stimulation can induce bidirectional shifts in motor cortical excitability in awake humans

    DEFF Research Database (Denmark)

    Groppa, S; Bergmann, T O; Siems, C;

    2010-01-01

    Constant transcranial direct stimulation (c-tDCS) of the primary motor hand area (M1(HAND)) can induce bidirectional shifts in motor cortical excitability depending on the polarity of tDCS. Recently, anodal slow oscillation stimulation at a frequency of 0.75 Hz has been shown to augment intrinsic...

  4. Pharmacological modulation of the short-lasting effects of antagonistic direct current-stimulation over the human motor cortex

    Directory of Open Access Journals (Sweden)

    Leila eChaieb

    2012-07-01

    Full Text Available Combined administration of transcranial direct current stimulation (tDCS with either pergolide (PGL or D-cycloserine (D-CYC can prolong the excitability-diminishing effects of cathodal, or the excitability enhancing effect of anodal stimulation for up to 24hrs poststimulation. However, it remains unclear whether the potentiation of the observed aftereffects is dominated by the polarity and duration of the stimulation, or the dual application of combined stimulation and drug administration. The present study looks at whether the aftereffects of oral administration of PGL (a D1/D2 agonist or D-CYC (a partial NMDA receptor agonist, in conjunction with the short duration antagonistic application of tDCS (either 5 min cathodal followed immediately by 5 min anodal or vice versa, that alone only induces short lasting aftereffects, can modulate cortical excitability in healthy human subjects, as revealed by a single-pulse MEP (motor-evoked-potential paradigm. Results indicate that the antagonistic application of DC currents induces short-term neuroplastic aftereffects that are dependent upon the polarity of the second application of short-duration tDCS. The application of D-cycloserine resulted in a reversal of this trend and so consequently a marked inhibition of cortical excitability with the cathodal-anodal stimulation order was observed. The administration of pergolide showed no significant aftereffects in either case. These results emphasise that the aftereffects of tDCS are dependent upon the stimulation orientation, and mirror the findings of other studies reporting the neuroplasticity inducing aftereffects of tDCS, and their prolongation when combined with the administration of CNS active drugs.

  5. Validation and quality control of replacement alternatives ?€“ current status and future challenges

    OpenAIRE

    Leist, Marcel; Hasiwa, Nina; Daneshian, Mardas; Hartung, Thomas

    2012-01-01

    Alternatives to animal testing have been developed mainly in the fields of toxicology and vaccine testing. Typical examples are the evaluation of phototoxicity, eye irritation or skin corrosion/irritation of cosmetics and industrial chemicals. However, examples can also be found in other biomedical areas, such the control of the quality of drug preparations for pyrogens or for the control of the production process of biologics, such as botulinum neurotoxin. For regulatory purposes, the qualit...

  6. ENIAK. Development of a non-motor injector coking test facility for alternative fuels; ENIAK. Entwicklung eines nichtmotorischen Injektorverkokungspruefstands fuer alternative Kraftstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, Hajo; Schloss, Heide vom; Yang, Zhi; Grote, Melanie [OWI Oel-Waerme-Institut GmbH, Aachen (Germany). Gruppe Anwendungstechnik

    2013-10-01

    Poor Biodiesel quality, contamination with copper and zinc as well as undesired reactions between (several) additives and biodiesel components are known causes for nozzle fouling. Therefore, among other things, all additives have to pass a no-harm test. The standard fouling tests are two engine tests: the XUD9-test (CEC F-23-01) and the DW-10-test (CEC DF 98-08). The XUD9 is a cost efficient, fast and proven testing method. It uses, however, an obsolete indirect injection diesel engine. The newer DW10 test is complex, costly and designed for high stress. This reduces the engine life and leads to a fuel consumption of approximately 1,000 l per test, both contributing to the high costs of the test. The main goal of the project ENIAK is the development, assembly, commissioning, and evaluation of a non-engine fuel injector test. It uses four complete common rail systems. The injection takes place in four self-designed reactors instead of an engine, and the fuel is not combusted, but re-condensed and pumped in a circle. If the test method proves to be as reliable as expected, it can be used as an alternative test method for injector fouling with low requirements regarding infrastructure on the testing site and sample volume. The project is funded by the the federal ministry of consumer protection, food and agriculture via FNR (''Fachagentur Nachwachsende Rohstoffe'', Agency for Renewable Resources). (orig.)

  7. How a charge conserving alternative to Maxwells displacement current entails a Darwin like approximation to the solutions of Maxwells equations

    CERN Document Server

    Wolsky, Alan M

    2014-01-01

    Though sufficient for local conservation of charge, Maxwells displacement current is not necessary. An alternative to the Ampere-Maxwell equation is exhibited and the alternatives electric and magnetic fields and scalar and vector potentials are expressed in terms of the charge and current densities. The magnetic field is shown to satisfy the Biot_Savart Law. The electric field is shown to be the sum of the gradient of a scalar potential and the time derivative of a vector potential which is different from but just as tractable as the simplest vector potential that yields the Biot_Savart Law The alternative describes a theory in which action is instantaneous and so may provide a good approximation to Maxwells equations where and when the finite speed of light can be neglected. The result recalls the Darwin approximation which arose from the study classical charged point particles to order (v/c)2 in the Lagrangian. Unlike Darwin, this approach does not depend on the constitution of the electric current. Instea...

  8. Alternating current for the West; Un courant alternatif pour le grand ouest

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    In the framework of the reactor EPR construction in the Manche, the authors wonder on the pertinence of this energy choice for the economy and the environment of the West France. They show that there is an alternative to this choice. In a first part a state of the situation concerning the electricity supply and demand in the region is detailed. Then from the local potential of renewable electric power production and the electricity conservation, they propose many concrete actions. (A.L.B.)

  9. Overview of Alternative Bunching and Current-shaping Techniques for Low-Energy Electron Beams

    Energy Technology Data Exchange (ETDEWEB)

    Piot, Philippe [Northern Illinois U.

    2015-12-01

    Techniques to bunch or shape an electron beam at low energies (E <15 MeV) have important implications toward the realization of table-top radiation sources [1] or to the design of compact multi-user free-electron lasers[2]. This paper provides an overview of alternative methods recently developed including techniques such as wakefield-based bunching, space-charge-driven microbunching via wave-breaking [3], ab-initio shaping of the electron-emission process [4], and phase space exchangers. Practical applications of some of these methods to foreseen free-electron-laser configurations are also briefly discussed [5].

  10. New algorithm to detect voltage disturbances in three phases alternative current systems

    Energy Technology Data Exchange (ETDEWEB)

    Benslimane, T.; Chetate, B. [University of Boumerdes (Algeria)

    2006-07-01

    In this paper is presented a new algorithm based on logical functions to detect different disturbances in alternative voltage in electrical power networks such as over-voltage, under-voltage, unbalanced voltage, short circuit besides the safe operating condition. This algorithm is based on RMS values of three phases voltages as input values to detection system that is basically based on logical functions. This system is applied on three phase electrical power network of sinusoidal voltage. It can also be applied on PWM voltage that must be filtered to get its fundamental RMS value. Simulation program was developed in Matlab/Simulinksoftware. Simulation results are presented. (orig.)

  11. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report first provides a description of the local community and economy near Sand Lake NWR. An analysis of current and proposed management strategies that could...

  12. Japanese Macroeconomic Policy and the Current Account Under Alternative International Monetary Regimes

    OpenAIRE

    John B. Taylor

    1988-01-01

    Empirical estimates of the effect of monetary and fiscal policy on the Japanese current account are provided. To assess the quantitative importance of international monetary factors, these estimates are computed under three different exchange rate regimes: flexible exchange rates, fixed exchange rates with a "yen standard" and fixed exchange rates with a "multi-currency standard." For all exchange rate regimes, monetary policy has a much smaller impact on the current account than fiscal polic...

  13. Characteristics of electric arc furnaces powered by a low-frequency alternating current

    Science.gov (United States)

    Mironov, Yu. M.; Mironova, A. N.

    2016-06-01

    The changes in the parameters of a DSP-100 electric arc furnace that are induced by a decrease in the current frequency are considered. It is shown that the related decrease in the current lead resistances causes an increase in the arc power and voltage, a decrease in the reactive power, and an increase in the electrical efficiency and the power coefficient. The heat indices are expected to be significantly improved.

  14. An alternative explanation for the occurrence of short circuit current increases in the small intestine following challenge by bacterial enterotoxins.

    Science.gov (United States)

    Lucas, M L

    2013-10-01

    Secretory diarrhoeal disease due to enterotoxins is thought to arise from the enhancement to pathologically high rates of normally occurring chloride ion and therefore fluid secretion from enterocytes. In support of this concept, many enterotoxins increase intestinal short-circuit current, regarded now as faithfully reflecting the increased chloride ion secretion. Contradicting this assumption, STa reduces absorption but does not cause secretion in vivo although short-circuit current is increased in vitro. There is therefore a mismatch between an assumed enterocyte mediated secretory event that should but does not cause net fluid secretion and an undoubtedly increased short-circuit current. It is proposed here that short-circuit current increases are not themselves secretory events but result from interrupted fluid absorption. A noteworthy feature of compounds that inhibit the increase in short-circuit current is that the majority are vasoactive, neuroactive or both. In general, vasodilator substances increase current. An alternative hypothesis for the origin of short-circuit current increases is that these result from reflex induction of electrogenic fluid absorption. This reflex enhances a compensatory response that is also present at a cellular level. An intestinal reflex is therefore proposed by which decreases in interstitial and intravascular volume or pressure within the intestine initiate an electrogenic fluid absorption mechanism that compensates for the loss of electrically neutral fluid absorption. This hypothesis would explain the apparently complex pharmacology of short-circuit current increases since many depressor substances have receptors in common with enterocytes and enteric nerves. The proposed alternative view of the origin of short-circuit current increases assumes that these do not represent chloride secretion from the enterocytes. This view may therefore aid the successful development of anti-diarrhoeal drugs to overcome a major cause of

  15. Development of alternating current transmitter of detection system for magnetic material in soil subsurface

    Science.gov (United States)

    Indrasari, Widyaningrum; Djamal, Mitra; Srigutomo, Wahyu; Ramli

    2016-03-01

    Generally, detection system for magnetic material in soil subsurface using electromagnetic induction method consists of two parts, they are transmitter and receiver unit. A transmitter must be able to produce a continuous and stable AC current at a certain frequency, meanwhile receiver should be able to catch the secondary magnetic field of magnetic material in soil subsurface. The aim of this study was to develop a new AC current transmitter of detection system for the magnetic material in soil subsurface. This paper will describe the results of the development of AC current transmitter systems, distance characterization of the sensor detection toward horizontal solenoid positions, and characterization of magnetic material in the soil subsurface. It has successfully made the AC current transmitter system, composed of a sinusoidal signal generator, power amplifier, and a source of AC magnetic field. The output of the generator has a frequency varies: 1 kHz, 2 kHz, 5 kHz, and 10 kHz. We found that the AC current transmitter that has been developed able to work properly up to a frequency of 10 kHz.

  16. Convection displacement current and alternative form of Maxwell-Lorentz equations

    CERN Document Server

    Chubykalo, A E; Chubykalo, Andrew E.; Smirnov-Rueda, Roman

    1996-01-01

    Some mathematical inconsistencies in the conventional form of Maxwell's equations extended by Lorentz for a single charge system are discussed. To surmount these in framework of Maxwellian theory, a novel convection displacement current is considered as additional and complementary to the famous Maxwell displacement current. It is shown that this form of the Maxwell-Lorentz equations is similar to that proposed by Hertz for electrodynamics of bodies in motion. Original Maxwell's equations can be considered as a valid approximation for a continuous and closed (or going to infinity) conduction current. It is also proved that our novel form of the Maxwell-Lorentz equations is relativistically invariant. In particular, a relativistically invariant gauge for quasistatic fields has been found to replace the non-invariant Coulomb gauge. The new gauge condition contains the famous relationship between electric and magnetic potentials for one uniformly moving charge that is usually a! ttributed to the Lorentz transfor...

  17. Characterization of CdS thin films electrodeposited by an alternating current electrolysis method

    International Nuclear Information System (INIS)

    Conventional electrochemical methods of making CdS films are anodic oxidation of cadmium in a solution containing sulfide ions, and cathodic reduction from solutions containing soluble metal and sulfur compounds. In this paper a method is presented in which a CdS layer is deposited by a.c. electrolysis. The substrate is a glass plate covered by a layer of tin oxide. The electrolyte is an aqueous solution containing cadmium sulphate, ammonium sulphate, sodium thiosulphate, sodium chloride and glycerol. The applied a.c. voltages correspond to symmetrical and asymmetrical rectangular waves. During the electrolysis two electrodes are alternately connected to positive and negative potentials. As a result, Cd/sup 2+/ and S/sup 2-/ particles deposit at each electrode by turns, which results in the formation of a CdS layer

  18. Determination of aniline in environmental water samples by alternating-current oscillopolarographic titration

    Institute of Scientific and Technical Information of China (English)

    Jun Ping Xiao; Qing Xiang Zhou; Xiao Ke Tian; Hua Hua Bai; Xian Fa Su

    2007-01-01

    A new method for the determination of aniline in environmental water based on oscillopolarographic titration was presented in this paper.Several factors including the kind, concentration, and volume of acid, the dosage of potassium bromide, the temperature and concentration of concomitant substances were investigated in detail.The experimental results indicated that this method was simple, rapid, and sensitive.The linear range was 8.367 x 10-4 to 2.789 x 10-2 mol L-1, the relative standard deviation (R.S.D.) was lower than 0.96%, and the spiked recoveries of aniline in environmental water samples were in the range of 99.4-106.9% under the optimal conditions.The results indicated that the present method could be used as an alternative method for aniline determination in realworld water samples.

  19. Motor Fuel Excise Taxes

    Energy Technology Data Exchange (ETDEWEB)

    2015-09-01

    A new report from the National Renewable Energy Laboratory (NREL) explores the role of alternative fuels and energy efficient vehicles in motor fuel taxes. Throughout the United States, it is common practice for federal, state, and local governments to tax motor fuels on a per gallon basis to fund construction and maintenance of our transportation infrastructure. In recent years, however, expenses have outpaced revenues creating substantial funding shortfalls that have required supplemental funding sources. While rising infrastructure costs and the decreasing purchasing power of the gas tax are significant factors contributing to the shortfall, the increased use of alternative fuels and more stringent fuel economy standards are also exacerbating revenue shortfalls. The current dynamic places vehicle efficiency and petroleum use reduction polices at direct odds with policies promoting robust transportation infrastructure. Understanding the energy, transportation, and environmental tradeoffs of motor fuel tax policies can be complicated, but recent experiences at the state level are helping policymakers align their energy and environmental priorities with highway funding requirements.

  20. Research of resisting of the biological active point for constant and alternative current

    Directory of Open Access Journals (Sweden)

    S. N. Peregudov

    2008-05-01

    Full Text Available Is conducted research of resistance of biologically active point (BAT on a direct and variable current. Research results are presented. The estimation of intercommunication between resistance of skin and by an electromagnetic radiation in BAT is done. Is shown possibility of the use of experimental information for diagnostics of the state of human to the organism.

  1. Multiple-Fault Detection Methodology Based on Vibration and Current Analysis Applied to Bearings in Induction Motors and Gearboxes on the Kinematic Chain

    Directory of Open Access Journals (Sweden)

    Juan Jose Saucedo-Dorantes

    2016-01-01

    Full Text Available Gearboxes and induction motors are important components in industrial applications and their monitoring condition is critical in the industrial sector so as to reduce costs and maintenance downtimes. There are several techniques associated with the fault diagnosis in rotating machinery; however, vibration and stator currents analysis are commonly used due to their proven reliability. Indeed, vibration and current analysis provide fault condition information by means of the fault-related spectral component identification. This work presents a methodology based on vibration and current analysis for the diagnosis of wear in a gearbox and the detection of bearing defect in an induction motor both linked to the same kinematic chain; besides, the location of the fault-related components for analysis is supported by the corresponding theoretical models. The theoretical models are based on calculation of characteristic gearbox and bearings fault frequencies, in order to locate the spectral components of the faults. In this work, the influence of vibrations over the system is observed by performing motor current signal analysis to detect the presence of faults. The obtained results show the feasibility of detecting multiple faults in a kinematic chain, making the proposed methodology suitable to be used in the application of industrial machinery diagnosis.

  2. Discussion on the no-load current of three-phase asynchronous motor%浅论三相异步电动机的空载电流

    Institute of Scientific and Technical Information of China (English)

    杨立峰; 郭宗跃; 牛玉敏

    2015-01-01

    该文对以往利用空载电流判断电动机修理质量的方法进行了分析,提出了根据功率因数cosφ和效率η之积的经验值进行经验额定电流计算的方法。并根据长期现场工作经验,针对不同类型的电动机,计算出的经验额定电流和实测的空载电流,给出了鉴定电动机修理质量的具体判断依据。%In this paper, we analysis the conventional method of using the no-load current to judge the quality of motor repairs. Presents mehtod according to the product empirical value of the power factor cosφand efifciencyηto caculate experience rated current.. Based on the long-term ifeld experience, for different types of motor, according to the experience rated current calculated and load current measured, eventually give a speciifc identiifcation basis for motor repair quality.

  3. Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells

    OpenAIRE

    Sheng-Nan Wu; Ming-Chun Hsu; Yu-Kai Liao; Fang-Tzu Wu; Yuh-Jyh Jong; Yi-Ching Lo

    2012-01-01

    Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (I K(DR)) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of I K(DR) inactivation rate was about 9.8  μ M. Neither linopirdine (10  μ M), NMD...

  4. The role of augmentative and alternative communication for children with autism: current status and future trends

    Directory of Open Access Journals (Sweden)

    Iacono T

    2016-09-01

    Full Text Available Teresa Iacono,1 David Trembath,2 Shane Erickson3 1Living with Disability Research Centre, La Trobe University, Bendigo, VIC, Australia; 2Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, Australia; 3Living with Disability Research Centre, La Trobe University, Melbourne, VIC, Australia Background: Augmentative and alternative communication (AAC interventions are used for children with autism, often as stand-alone communication interventions for those who are minimally verbal. Our aim was to synthesize the evidence for AAC interventions for children (up to 21 years, and then consider the role of AAC within established, comprehensive, evidence-based autism interventions targeting learning across multiple developmental domains.Design: We completed a systematic search of three databases (OVID Medline, PsycINFO, ERIC as well as forward citation and hand searches to identify systematic reviews of AAC intervention efficacy research including children with autism, published between 2000 and March 2016 in peer-reviewed journals. Data pertaining to the quality indicators of included studies, effect sizes for intervention outcomes, and evidence for effectiveness were extracted for descriptive analysis.Results: The search yielded 17 systematic reviews. Most provided indicators of research quality for included studies, of which only relatively few provided conclusive results. Communication targets tended to be focused on teaching children to make requests. Still, effect size measures for included studies indicated that AAC was effective to highly effective.Conclusion: There is growing evidence for the potential benefits of AAC for children with autism, but there is a need for more well-designed studies and broader, targeted outcomes. Furthermore, a lack of evidence for the role of AAC within comprehensive intervention programs may account for a tendency by autism researchers and practitioners to neglect this intervention. Attempts to

  5. COMPARISON THE EFFECT OF SIMULTANEOUS SENSORY STIMULATION AND CURRENT OCCUPATIONAL THERAPY APPROACHES ON MOTOR DEVELOPMENT OF THE INFANTS WITH DOWN SYNDROME

    Directory of Open Access Journals (Sweden)

    Masoud KARIMLOO

    2010-11-01

    Full Text Available AbstractObjectiveNeuromuscular characteristics in Down syndrome result in generalized muscular hypotonia, developmental delays and sensory integration deficits. The aim of this study was to compare the effects of simultaneous sensory stimulations and current occupational therapy approaches on motor functions development of infants with Down syndrome.Materials & MethodsEighteen infants with Down syndrome, aged 6 -18 months, were evaluated in two groups: intervention group (simultaneous sensory stimulation and occupational therapy and control group (occupational therapy alone. They attended the program 3 times a week for 6 months and each session lasted 45 minutes. Motor functions were assessed before, during, and after intervention in the two groups, using GMFM test.ResultsMean motor function increased in both groups according to the GMFM test (P = 0.000. Comparison of the changes showed that although the mean difference of this variable was higher in the intervention group, the difference was not statistically significant (P = 0.576.Mean motor deficit reduced in both groups during the period of the study,which was statistically significant (P < 0.05. Comparison of the difference in mean motor deficit in the first and last evaluations showed that this difference was more in the intervention group but statistically insignificant (P = 0.617ConclusionEarly use of simultaneous sensory stimulations can improve the quality of motor skills in Down syndrome infants. It is suggested that it may be used as an early intervention in association with other methods in the rehabilitation of these patients. However, more studies in this regard are warranted.

  6. Use of Biosensors as Alternatives to Current Regulatory Methods for Marine Biotoxins

    OpenAIRE

    Botana, Luis M.; M. Carmen Louzao; Natalia Vilariño; Fonfría, Eva S.

    2009-01-01

    Marine toxins are currently monitored by means of a bioassay that requires the use of many mice, which poses a technical and ethical problem in many countries. With the exception of domoic acid, there is a legal requirement for the presence of other toxins (yessotoxin, saxitoxin and analogs, okadaic acid and analogs, pectenotoxins and azaspiracids) in seafood to be controlled by bioassay, but other toxins, such as palytoxin, cyclic imines, ciguatera and tetrodotoxin are potentially present in...

  7. Analysis of current and alternative phenol based RNA extraction methodologies for cyanobacteria

    Directory of Open Access Journals (Sweden)

    Lindblad Peter

    2009-08-01

    Full Text Available Abstract Background The validity and reproducibility of gene expression studies depend on the quality of extracted RNA and the degree of genomic DNA contamination. Cyanobacteria are gram-negative prokaryotes that synthesize chlorophyll a and carry out photosynthetic water oxidation. These organisms possess an extended array of secondary metabolites that impair cell lysis, presenting particular challenges when it comes to nucleic acid isolation. Therefore, we used the NHM5 strain of Nostoc punctiforme ATCC 29133 to compare and improve existing phenol based chemistry and procedures for RNA extraction. Results With this work we identify and explore strategies for improved and lower cost high quality RNA isolation from cyanobacteria. All the methods studied are suitable for RNA isolation and its use for downstream applications. We analyse different Trizol based protocols, introduce procedural changes and describe an alternative RNA extraction solution. Conclusion It was possible to improve purity of isolated RNA by modifying protocol procedures. Further improvements, both in RNA purity and experimental cost, were achieved by using a new extraction solution, PGTX.

  8. The Polarization of a Diffuse Soft Particle Subjected to an Alternating Current Field

    Science.gov (United States)

    Uppapalli, Sebastian; Zhao, Hui

    2012-11-01

    The polarization of a diffuse soft particle submerged in an aqueous electrolyte and subjected to a uniform, alternating electric field is theoretically analyzed with the standard electrokinetic model. The particle consists of a rigid uncharged core and a charged diffuse polyelectrolytic shell (soft layer), permeable to ions and solvent. Our focus is on the impact of the characteristics of the soft layer including Donnan potential, the soft layer thickness and the friction coefficient of the soft layer on the dipole coefficient, characterizing the strength of the polarization. Under the limits of thin double layers and thin polyelectrolytic shells, approximate, analytical expressions to evaluate dipole moment coefficients are derived, respectively, for high-frequency and low-frequency ranges. The analytical results are compared and agree favorably with those numerically computed by the standard model. Interestingly, we discover that when the double layer is comparable to the soft layer, the dipole moment behaves qualitatively differently at different Donnan potentials. When the Donnan potential is small, the dipole moment decreases as the double layer increases. In contrast, at large Donnan potentials, the dipole moment increases with the increase of the double layer. The distinct responses to Donnan potentials are attributed to the impact of the associated double layer on the charge distribution of mobile ions inside the soft layer. The theoretical model provides a fundamental basis for interpreting the polarization of heterogeneous systems including environmental or biological colloids or microgel particles.

  9. Accelerated test methods for predicting the life of motor materials exposed to refrigerant/lubricant mixtures. Phase 1, Conceptual design: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, P.F. II; Ferguson, A.

    1993-08-18

    The federally mandated phase-out of chlorofluorocarbon refrigerants requires screening tests for motor materials compatibility with alternative refrigerant/lubricant mixtures. In the current phase of the program, ARTI is supporting tests of promising candidate refrigeration/lubricant systems in key refrigeration component systems such as bearings and hermetic motor insulation systems to screen for more subtle detrimental effects and allow estimates of motor-compressor life. This report covers: mechanisms of failure of hermetic motor insulation, current methods for estimation of life of hermetic motors, and conceptual design of improved stator simulator device for testing of alternative refrigerant/lubricant mixtures.

  10. Effects of alternating current imposition and alkaline earth elements on modification of primary Mg_2Si crystals in hypereutectic Mg-Si alloy

    Institute of Scientific and Technical Information of China (English)

    DU Jun; K. IWAI; LI Wen-fang; PENG Ji-hua

    2009-01-01

    The effects of alternating current imposition and/or alkaline earth elements on modification of the primary Mg_2Si crystals in the hypereutectic Mg-Si alloy were investigated. An alternating current of 60 A with frequency of 1 kHz was applied into the hypereutectic Mg-Si melt which was alloyed with alkaline earth elements or not in the fixed temperature range from 700 to 630 ℃. The results show that the primary Mg_2Si crystals could be refined by imposing alternating current or adding alkaline elements. Compared with the samples treated by adding 0.4% Ca or 0.4% Sr, higher modification efficiency could be obtained for the samples treated by imposing alternating current. No further modification efficiency could be obtained for the samples treated by imposing alternating current combined with 0.4% Ca or 0.4% Sr addition.

  11. Regional economic effects of current and proposed management alternatives for Arrowwood National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Arrowwood National Wildlife Refuge (NWR), located along the James River in east central North Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Arrowwood NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  12. Regional economic effects of current and proposed management alternatives for Sand Lake National Wildlife Refuge

    Science.gov (United States)

    Koontz, Lynne; Lambert, Heather

    2005-01-01

    The National Wildlife Refuge System Improvement Act of 1997 requires all units of the National Wildlife Refuge System to be managed under a Comprehensive Conservation Plan (CCP). The CCP must describe the desired future conditions of a Refuge and provide long range guidance and management direction to achieve Refuge purposes. Sand Lake National Wildlife Refuge (NWR), located 27 miles northeast of Aberdeen, South Dakota, is in the process of developing a range of management goals, objectives, and strategies for the CCP. The CCP for Sand Lake NWR must contain an analysis of expected effects associated with current and proposed Refuge management strategies.

  13. THE MOTOR ACTIVITY IN THE SECONDARY SCHOOL IN OUR COUNTRY NOT AFFECTED BY THE CURRENT GLOBAL CRISIS

    Directory of Open Access Journals (Sweden)

    Lecturer MARCONI ROBERTO GABRIEL, Phd

    2012-12-01

    Full Text Available In this period of global crisis the motor activity at the level of the secondary school from our country did not stagnate, on the contrary it achieved a special development due to an increase in the number of stu- dents (pupils eager to practice the motor activity, as a result of the improvement of the material equipment with more than 40 simple and complex stadiums of various gymnastics, judo and karate courts, equipped with minifootball, handball, basketball and volleyabll courts. But the most important thing is to provide professionals belonging to the field of physical education within the Universities of Arad up to the present and also in the future.

  14. The role of augmentative and alternative communication for children with autism: current status and future trends

    Science.gov (United States)

    Iacono, Teresa; Trembath, David; Erickson, Shane

    2016-01-01

    Background Augmentative and alternative communication (AAC) interventions are used for children with autism, often as stand-alone communication interventions for those who are minimally verbal. Our aim was to synthesize the evidence for AAC interventions for children (up to 21 years), and then consider the role of AAC within established, comprehensive, evidence-based autism interventions targeting learning across multiple developmental domains. Design We completed a systematic search of three databases (OVID Medline, PsycINFO, ERIC) as well as forward citation and hand searches to identify systematic reviews of AAC intervention efficacy research including children with autism, published between 2000 and March 2016 in peer-reviewed journals. Data pertaining to the quality indicators of included studies, effect sizes for intervention outcomes, and evidence for effectiveness were extracted for descriptive analysis. Results The search yielded 17 systematic reviews. Most provided indicators of research quality for included studies, of which only relatively few provided conclusive results. Communication targets tended to be focused on teaching children to make requests. Still, effect size measures for included studies indicated that AAC was effective to highly effective. Conclusion There is growing evidence for the potential benefits of AAC for children with autism, but there is a need for more well-designed studies and broader, targeted outcomes. Furthermore, a lack of evidence for the role of AAC within comprehensive intervention programs may account for a tendency by autism researchers and practitioners to neglect this intervention. Attempts to compare evidence for AAC with other interventions for children with autism, including those in which the use of AAC is delayed or excluded in pursuit of speech-only communication, must take into account the needs of children with the most significant learning needs. These children pose the greatest challenges to achieving large

  15. Thermal Dissipation Modelling and Design of ITER PF Converter Alternating Current Busbar

    Science.gov (United States)

    Guo, Bin; Song, Zhiquan; Fu, Peng; Jiang, Li; Li, Jinchao; Wang, Min; Dong, Lin

    2016-10-01

    Because the larger metallic surrounds are heated by the eddy current, which is generated by the AC current flowing through the AC busbar in the International Thermonuclear Experimental Reactor (ITER) poloidal field (PF) converter system, shielding of the AC busbar is required to decrease the temperature rise of the surrounds to satisfy the design requirement. Three special types of AC busbar with natural cooling, air cooling and water cooling busbar structure have been proposed and investigated in this paper. For each cooling scheme, a 3D finite model based on the proposed structure has been developed to perform the electromagnetic and thermal analysis to predict their operation behavior. Comparing the analysis results of the three different cooling patterns, water cooling has more advantages than the other patterns and it is selected to be the thermal dissipation pattern for the AC busbar of ITER PF converter unit. The approach to qualify the suitable cooling scheme in this paper can be provided as a reference on the thermal dissipation design of AC busbar in the converter system. supported by National Natural Science Foundation of China (No. 51407179)

  16. Transient analysis of converter-fed variable-speed generator-motor for pumped storage power plant. Relationship between fault current and speed variation; Kahensoku yosui hatsuden system no koshoji kato tokusei kaiseki. Kaiten sokudo henka no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Yanagisawa, T.; Kageyama, T.; Okamura, K.; Kusunoki, K. [Toshiba Corp., Tokyo (Japan); Taguchi, T.; Abe, M.; Kaneko, H. [Tokyo Electric Power Co. Inc., Tokyo (Japan)

    1995-11-20

    A converter-fed variable-speed generator-motor for a pumped storage power plant has been developed in order to contribute to the automatic frequency control on an electric power system during pumping operations, as well as to improve the efficiency of turbines during generating operation together with electric power stability. This system consists of a reversible pump-turbine, generator-motor, cycloconverter and control units. The rotor of the generator-motor, which is coupled directly with the turbine runner, is normally operated at a rotating speed equal to the difference between the frequency of the electric power system and that of the rotor current. In the state that a fault has occurred in the primary circuit of the generator-motor, the variable-speed rotating speed varies and the generator-motor fault current differs from that of a conventional synchronous generator-motor. We have previously reported the fault current analysis results on the assumption that the rotating-speed of the generator-motor does not vary during the fault. However the rotating-speed of the generator-motor does vary during the fault, therefore this paper describes the fault current analysis results without this assumption for the condition when a sudden short-circuit is made on the primary side or secondary side of the generator-motor, and collates the analysis results with the EMTP simulation results. 8 refs., 10 figs.

  17. Bihemispheric Motor Cortex Transcranial Direct Current Stimulation Improves Force Steadiness in Post-Stroke Hemiparetic Patients: A Randomized Crossover Controlled Trial

    Science.gov (United States)

    Montenegro, Rafael A.; Midgley, Adrian; Massaferri, Renato; Bernardes, Wendell; Okano, Alexandre H.; Farinatti, Paulo

    2016-01-01

    Post-stroke patients usually exhibit reduced peak muscular torque (PT) and/or force steadiness during submaximal exercise. Brain stimulation techniques have been proposed to improve neural plasticity and help to restore motor performance in post-stroke patients. The present study compared the effects of bihemispheric motor cortex transcranial direct current stimulation (tDCS) on PT and force steadiness during maximal and submaximal resistance exercise performed by post-stroke patients vs. healthy controls. A double-blind randomized crossover controlled trial (identification number: TCTR20151112001; URL: http://www.clinicaltrials.in.th/) was conducted involving nine healthy and 10 post-stroke hemiparetic individuals who received either tDCS (2 mA) or sham stimulus upon the motor cortex for 20 min. PT and force steadiness (reflected by the coefficient of variation (CV) of muscular torque) were assessed during unilateral knee extension and flexion at maximal and submaximal workloads (1 set of 3 repetitions at 100% PT and 2 sets of 10 repetitions at 50% PT, respectively). No significant change in PT was observed in post-stroke and healthy subjects. Force steadiness during knee extension (~25–35%, P knee extension (~13–27%, P < 0.001) in healthy controls. These results suggest that tDCS may improve force steadiness, but not PT in post-stroke hemiparetic patients, which might be relevant in the context of motor rehabilitation programs. PMID:27601988

  18. The effect of anodal transcranial direct current stimulation on motor sequence learning in healthy individuals: A systematic review and meta-analysis.

    Science.gov (United States)

    Hashemirad, Fahimeh; Zoghi, Maryam; Fitzgerald, Paul B; Jaberzadeh, Shapour

    2016-02-01

    A large number of studies have indicated the effect of anodal transcranial direct current stimulation (a-tDCS) on the primary motor cortex (M1) during motor skill training. The effects of a-tDCS on different stages of motor sequence learning are not yet completely understood. The purpose of this meta-analysis was to determine the effects of single and multiple sessions of a-tDCS on two different tasks: the sequential finger tapping task/serial reaction time task (SEQTAP/SRTT) and the sequential visual isometric pinch task (SVIPT). We searched electronic databases for M1 a-tDCS studies. Thirteen studies met the inclusion criteria. The results indicate that application of multiple sessions of a-tDCS, compared to single session a-tDCS induced a significant improvement in skill in both SEQTAP/SRTT and SVIPT. Retention after a single day and multiple days of a-tDCS was statistically significant for the SEQTAP/SRTT task but not for SVIPT. Therefore, our findings suggest that application of M1 a-tDCS across the three or five consecutive days can be helpful to improve motor sequence learning.

  19. Potential alternatives to edible oils for biodiesel production - A review of current work

    International Nuclear Information System (INIS)

    Biodiesel production is a very modern and technological area for researchers due to the relevance that it is winning everyday because of the increase in the petroleum price and the environmental advantages. Currently, biodiesel is mainly prepared from conventionally grown edible oils such as rapeseed, soybean, sunflower and palm thus leading to alleviate food versus fuel issue. About 7% of global vegetable oil supplies were used for biodiesel production in 2007. Extensive use of edible oils may cause other significant problems such as starvation in developing countries. The use of non-edible plant oils when compared with edible oils is very significant in developing countries because of the tremendous demand for edible oils as food, and they are far too expensive to be used as fuel at present. The production of biodiesel from different non-edible oilseed crops has been extensively investigated over the last few years. (author)

  20. Including Alternative Resources in State Renewable Portfolio Standards: Current Design and Implementation Experience

    Energy Technology Data Exchange (ETDEWEB)

    Heeter, J.; Bird, L.

    2012-11-01

    Currently, 29 states, the District of Columbia, and Puerto Rico have instituted a renewable portfolio standard (RPS). An RPS sets a minimum threshold for how much renewable energy must be generated in a given year. Each state policy is unique, varying in percentage targets, timetables, and eligible resources. This paper examines state experience with implementing renewable portfolio standards that include energy efficiency, thermal resources, and non-renewable energy and explores compliance experience, costs, and how states evaluate, measure, and verify energy efficiency and convert thermal energy. It aims to gain insights from the experience of states for possible federal clean energy policy as well as to share experience and lessons for state RPS implementation.

  1. Asynchronous recruitment of low-threshold motor units during repetitive, low-current stimulation of the human tibial nerve

    Directory of Open Access Journals (Sweden)

    Jesse eDean

    2014-12-01

    Full Text Available Motoneurons receive a barrage of inputs from descending and reflex pathways. Much of our understanding about how these inputs are transformed into motor output in humans has come from recordings of single motor units during voluntary contractions. This approach, however, is limited because the input is ill-defined. Herein, we quantify the discharge of soleus motor units in response to well-defined trains of afferent input delivered at physiologically-relevant frequencies. Constant frequency stimulation of the tibial nerve (10-100 Hz for 30 s, below threshold for eliciting M-waves or H-reflexes with a single pulse, recruited motor units in 7/9 subjects. All 25 motor units recruited during stimulation were also recruited during weak (<10% MVC voluntary contractions. Higher frequencies recruited more units (n=3/25 at 10 Hz; n=25/25 at 100 Hz at shorter latencies (19.4±9.4 s at 10 Hz; 4.1±4.0 s at 100 Hz than lower frequencies. When a second unit was recruited, the discharge of the already active unit did not change, suggesting that recruitment was not due to increased synaptic drive. After recruitment, mean discharge rate during stimulation at 20 Hz (7.8 Hz was lower than during 30 Hz (8.6 Hz and 40 Hz (8.4 Hz stimulation. Discharge was largely asynchronous from the stimulus pulses with time-locked discharge occurring at an H-reflex latency with only a 24% probability. Motor units discharged after the stimulation ended in 89% of trials, although at a lower rate (5.8 Hz than during the stimulation (7.9 Hz. This work supports the idea that the afferent volley evoked by repetitive stimulation recruits motor units through the integration of synaptic drive and intrinsic properties of motoneurons, resulting in physiological recruitment which adheres to Henneman's size principle and results in relatively low discharge rates and asynchronous firing.

  2. Analysis of operations and cyber security policies for a system of cooperating Flexible Alternating Current Transmission System (FACTS) devices.

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, Laurence R.; Tejani, Bankim; Margulies, Jonathan; Hills, Jason L.; Richardson, Bryan T.; Baca, Micheal J.; Weiland, Laura

    2005-12-01

    Flexible Alternating Current Transmission Systems (FACTS) devices are installed on electric power transmission lines to stabilize and regulate power flow. Power lines protected by FACTS devices can increase power flow and better respond to contingencies. The University of Missouri Rolla (UMR) is currently working on a multi-year project to examine the potential use of multiple FACTS devices distributed over a large power system region in a cooperative arrangement in which the FACTS devices work together to optimize and stabilize the regional power system. The report describes operational and security challenges that need to be addressed to employ FACTS devices in this way and recommends references, processes, technologies, and policies to address these challenges.

  3. Alternating current-driven microwave loss modulation in a fluxonic metamaterial

    Science.gov (United States)

    Dobrovolskiy, Oleksandr V.; Huth, Michael; Shklovskij, Valerij A.

    2015-10-01

    We introduce a fluxonic metamaterial on the basis of nanopatterned superconducting Nb microstrips and employ it for modulation and synthesis of quantized loss levels in the lower GHz range by a sine-wave quasistatic ac drive. The nanopatterns are uniaxial nanogrooves with identical and different slope steepness, which induce a pinning potential of the washboard type for Abrikosov vortices. For the fundamental matching field, when the location of vortex rows geometrically matches the nanogrooves, the following effects are observed: The forward transmission coefficient S21(f) of the microstrips can be controllably modulated within a range of about 3 dB by the ac. For the sample with symmetric grooves, depending on the choice of the operation point in the current-voltage curve, the shape and the duty cycle of the output signal can be tuned. For the sample with asymmetric grooves, depending on the ac amplitude, a sine-to-triangular or a sine-to-rectangular pulse shape conversion is observed. The possibility of synthesizing quantized loss levels by a serial connection of the two samples with different nanopatterns is exemplified and can be used for the development of multilevel excess-loss-based fluxonic devices.

  4. The effects of ultrasound and alternating current on the laser penetration in the tissue.

    Science.gov (United States)

    Dawood, Munqith Saleem

    2016-07-01

    The visible (VIS) and near-infrared (NIR) lasers are now widely used in therapeutic and other medical applications. Some of these applications require to deliver the laser energy deep toward the desired tissue target or organ. The aim of this in vitro study is to investigate practically whether the modulation of laser energy by employing the therapeutic ultrasound or electrical energies can increase the penetration depth of the laser light inside the tissue. Such modulation was implemented in this study by coupling the (c.w.) diode and Nd:YAG laser energies with the ultrasound or AC current simultaneously as they pass through preprepared ex vivo bovine muscular tissue strips. Two wavelengths of diode lasers were used, 637 and 808 nm beside the 1064-nm Nd:YAG laser. The results showed a noticeable decrease of these laser attenuation factors as they pass through the tissue strips in the presence of the ultrasound or AC energies. By using this coupling modulation, the capability of increasing the laser penetration depths inside the tissue was confirmed without having to increase their applied power. PMID:27098338

  5. Direct current in the future. HVDC better than a high-voltage alternating current cable; Gelijk in de toekomst. HVDC-verbonding beter dan hoogspanningskabel met wisselstroom

    Energy Technology Data Exchange (ETDEWEB)

    Van Velzen, T.

    2010-10-01

    For the development of a pan-European high-voltage grid the application of direct current (DC) technology is obvious. However, a series of incidents involving a link between the Netherlands and Norway raises questions about the reliability. An alternative conversion method seems more suited for a European supernetwork. DC transmission with insulated-gate bipolar transistor is the technology of the future. [Dutch] Voor de ontwikkeling van een pan-Europees hoogspanningsnet ligt toepassing van gelijkstroomtechnologie voor de hand. Een reeks incidenten met zo'n verbinding tussen Nederland en Noorwegen roept echter vragen op over de betrouwbaarheid. Een alternatieve conversietechniek lijkt echter geschikter voor een Europees supernet. Gelijkstroomtransmissie met 'insulated-gate bipolar' transistors is de techniek van de toekomst.

  6. Augmentative and alternative communication for children with autism spectrum disorder: An evidence-based evaluation of the Language Acquisition through Motor Planning (LAMP programme

    Directory of Open Access Journals (Sweden)

    Mary-Ann Naguib Bedwani

    2015-12-01

    Full Text Available Children diagnosed with autism spectrum disorder often have restricted verbal communication. For children who do not use functional speech, augmentative and alternative communication (AAC devices can be an important support. We evaluated the effectiveness of one AAC programme, the Language Acquisition through Motor Planning (LAMP using a Vantage Lite™ device as the speech output in the home and school environments. Eight children with limited communication were assessed by a speech pathologist prior to the introduction of the programme, after five weeks of training and again after a further two weeks of use of the programme, but without the supported training. The pre-/post-assessment measures revealed that all eight children made gains in the development of spontaneous communication using the device during the implementation period. Parents and teachers also reported that the gains achieved during the five-week trial were greater than those achieved in previous interventions. Two years after the completion of the study, a follow-up phone interview was completed which identified that children who received ongoing support from a LAMP-trained speech pathologist continued using the LAMP programme. As a result of this study, a specialised LAMP-specific classroom was established in one of the participating schools.

  7. Electro-optically responsive composites of gold nanospheres in 5CB liquid crystal under direct current and alternating current joint action

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B.; Marinov, Yordan G.; Petrov, Alexander G. [Institute of Solid State Physics, Bulgarian Academy of Sciences, Sofia 1784 (Bulgaria); Bruno, Emanuela [Dipartimento di Fisica, Università della Calabria, Via Pietro Bucci, Cubo 31C, 87036 Rende (CS) (Italy); Marino, Lucia, E-mail: lucia.marino@fis.unical.it [CNR-IPCF UoS di Cosenza, Licryl Laboratory, and Centro di Eccellenza CEMIF.CAL, Università della Calabria, 87036 Rende (CS) (Italy); Scaramuzza, Nicola [Dipartimento di Fisica, Università della Calabria, Via Pietro Bucci, Cubo 31C, 87036 Rende (CS) (Italy); CNR-IPCF UoS di Cosenza, Licryl Laboratory, and Centro di Eccellenza CEMIF.CAL, Università della Calabria, 87036 Rende (CS) (Italy)

    2014-02-28

    Direct current (DC) electro-optical (EO) control of transmitted laser beam intensity based on EO controlled coherent light scattering and diffraction by stationary longitudinal texture pattern (LTP) is achieved in planar-oriented cells with a composite mixture of polymer-coated gold spherical nanoparticles (Au-NPs) with a mean diameter of about 12 nm and the room-temperature nematic pentylcyanobiphenyl (5CB). At relatively low DC voltage of about 5 V, the effective scattering/diffraction by Au-NPs/5CB composites leads to a spatial spreading of transmitted coherent light from a low-power continuous wave laser beam, resulting in a drastic reduction of its local intensity. The effect is polarization dependent and is strongest when the polarization of the input laser beam is along the LTP. The EO response of Au-NPs/5CB mixtures is studied under DC and alternating current (AC) joint action with the aim of the potential use of these composite materials as EO controlled diffusers. The specific V-shaped sharp dip in the DC voltage-dependent coherent light transmittance of Au-NPs/5CB planar films, as well as the possibility for erasing the scattering/diffractive LTP in the films by joint low AC voltage, can be useful for EO applications in the field of process control and for detection of weak dynamic electric fields.

  8. Evidence for Inhibitory Effects of Flupirtine, a Centrally Acting Analgesic, on Delayed Rectifier K+ Currents in Motor Neuron-Like Cells

    Directory of Open Access Journals (Sweden)

    Sheng-Nan Wu

    2012-01-01

    Full Text Available Flupirtine (Flu, a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K+ currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K+ current (IK(DR with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of IK(DR inactivation rate was about 9.8 μM. Neither linopirdine (10 μM, NMDA (30 μM, nor gabazine (10 μM reversed Flu-induced changes in IK(DR inactivation. Addition of Flu shifted the inactivation curve of IK(DR to a hyperpolarized potential. Cumulative inactivation for IK(DR was elevated in the presence of this compound. Flu increased the amplitude of M-type K+ current (IK(M and produced a leftward shift in the activation curve of IK(M. In another neuronal cells (NG108-15, Flu reduced IK(DR amplitude and enhanced the inactivation rate of IK(DR. The results suggest that Flu acts as an open-channel blocker of delayed-rectifier K+ channels in motor neurons. Flu-induced block of IK(DR is unlinked to binding to NMDA or GABA receptors and the effects of this agent on K+ channels are not limited to its action on M-type K+ channels.

  9. Alternating-Current InGaN/GaN Tunnel Junction Nanowire White-Light Emitting Diodes.

    Science.gov (United States)

    Sadaf, S M; Ra, Y-H; Nguyen, H P T; Djavid, M; Mi, Z

    2015-10-14

    The current LED lighting technology relies on the use of a driver to convert alternating current (AC) to low-voltage direct current (DC) power, a resistive p-GaN contact layer to inject positive charge carriers (holes) for blue light emission, and rare-earth doped phosphors to down-convert blue photons into green/red light, which have been identified as some of the major factors limiting the device efficiency, light quality, and cost. Here, we show that multiple-active region phosphor-free InGaN nanowire white LEDs connected through a polarization engineered tunnel junction can fundamentally address the afore-described challenges. Such a p-GaN contact-free LED offers the benefit of carrier regeneration, leading to enhanced light intensity and reduced efficiency droop. Moreover, through the monolithic integration of p-GaN up and p-GaN down nanowire LED structures on the same substrate, we have demonstrated, for the first time, AC operated LEDs on a Si platform, which can operate efficiently in both polarities (positive and negative) of applied voltage.

  10. Alternating-Current InGaN/GaN Tunnel Junction Nanowire White-Light Emitting Diodes.

    Science.gov (United States)

    Sadaf, S M; Ra, Y-H; Nguyen, H P T; Djavid, M; Mi, Z

    2015-10-14

    The current LED lighting technology relies on the use of a driver to convert alternating current (AC) to low-voltage direct current (DC) power, a resistive p-GaN contact layer to inject positive charge carriers (holes) for blue light emission, and rare-earth doped phosphors to down-convert blue photons into green/red light, which have been identified as some of the major factors limiting the device efficiency, light quality, and cost. Here, we show that multiple-active region phosphor-free InGaN nanowire white LEDs connected through a polarization engineered tunnel junction can fundamentally address the afore-described challenges. Such a p-GaN contact-free LED offers the benefit of carrier regeneration, leading to enhanced light intensity and reduced efficiency droop. Moreover, through the monolithic integration of p-GaN up and p-GaN down nanowire LED structures on the same substrate, we have demonstrated, for the first time, AC operated LEDs on a Si platform, which can operate efficiently in both polarities (positive and negative) of applied voltage. PMID:26384135

  11. Signature of cluster disruption within magnetic fluid samples: The key information provided by low frequency alternating current susceptibility measurements

    Science.gov (United States)

    Du, Zhongzhou; Liu, Wenzhong; Zhong, Jing; Zhou, Ming; Zhang, Pu; Cesar Morais, Paulo

    2014-05-01

    This paper is focused on the signature of thermal-assisted cluster disruption while analyzing the inverse alternating current (AC) susceptibility (1/χ) versus temperature (T) curves recorded at lower AC frequencies (f), below 300 Hz. A commercial oil-based magnetic fluid (MF) sample was used in the experiments to investigate the critical temperature (T*) that characterizes the thermal disruption of aggregates suspended within the MF sample. T* was found to reduce as f increased within the frequency range of our investigation (63-263 Hz). Furthermore, T* was found to scale with the square of the applied AC frequency. Both theoretical and experimental evidences support that the excitation field frequency (f) dependence of the critical temperature (T*) is well described by T*(f)=T*(0)-Af/21+Bf2. The model is based on energy absorption of magnetic nanoparticles in an AC magnetic field.

  12. Characterization of interference thin films grown on stainless steel surface by alternate pulse current in a sulphochromic solution

    Directory of Open Access Journals (Sweden)

    Rosa Maria Rabelo Junqueira

    2008-12-01

    Full Text Available The aim of this work was to characterize thin interference films grown on the surface of AISI 304 stainless steel for decorative purposes. Films were grown in a sulphochromic solution at room temperature by an alternating pulse current method. The morphology and chemical state of the elements in the films were investigated by field emission scanning electron microscopy (FESEM, atomic force microscopy (AFM, glow discharge optical emission spectrometry (GDOES, and infrared Fourier transform spectroscopy (FTIR. Depth-sensing indentation (DSI experiments and wear abrasion tests were employed to assess the mechanical resistance of the films. The coloration process resulted in porous thin films which increased the surface roughness of the substrate. The interference films mainly consisted of hydrated chromium oxide containing iron. Increasing film thickness produced different colors and affected the mechanical properties of the coating-substrate system. Thicker films, such as those producing gold and green colors, were softer but more abrasion resistant.

  13. Elicitors as alternative strategy to pesticides in grapevine? Current knowledge on their mode of action from controlled conditions to vineyard.

    Science.gov (United States)

    Delaunois, Bertrand; Farace, Giovanni; Jeandet, Philippe; Clément, Christophe; Baillieul, Fabienne; Dorey, Stéphan; Cordelier, Sylvain

    2014-04-01

    Development and optimisation of alternative strategies to reduce the use of classic chemical inputs for protection against diseases in vineyard is becoming a necessity. Among these strategies, one of the most promising consists in the stimulation and/or potentiation of the grapevine defence responses by the means of elicitors. Elicitors are highly diverse molecules both in nature and origins. This review aims at providing an overview of the current knowledge on these molecules and will highlight their potential efficacy from the laboratory in controlled conditions to vineyards. Recent findings and concepts (especially on plant innate immunity) and the new terminology (microbe-associated molecular patterns, effectors, etc.) are also discussed in this context. Other objectives of this review are to highlight the difficulty of transferring elicitors use and results from the controlled conditions to the vineyard, to determine their practical and effective use in viticulture and to propose ideas for improving their efficacy in non-controlled conditions. PMID:23719689

  14. Bihemispheric Motor Cortex Transcranial Direct Current Stimulation Improves Force Steadiness in Post-Stroke Hemiparetic Patients: A Randomized Crossover Controlled Trial.

    Science.gov (United States)

    Montenegro, Rafael A; Midgley, Adrian; Massaferri, Renato; Bernardes, Wendell; Okano, Alexandre H; Farinatti, Paulo

    2016-01-01

    Post-stroke patients usually exhibit reduced peak muscular torque (PT) and/or force steadiness during submaximal exercise. Brain stimulation techniques have been proposed to improve neural plasticity and help to restore motor performance in post-stroke patients. The present study compared the effects of bihemispheric motor cortex transcranial direct current stimulation (tDCS) on PT and force steadiness during maximal and submaximal resistance exercise performed by post-stroke patients vs. healthy controls. A double-blind randomized crossover controlled trial (identification number: TCTR20151112001; URL: http://www.clinicaltrials.in.th/) was conducted involving nine healthy and 10 post-stroke hemiparetic individuals who received either tDCS (2 mA) or sham stimulus upon the motor cortex for 20 min. PT and force steadiness (reflected by the coefficient of variation (CV) of muscular torque) were assessed during unilateral knee extension and flexion at maximal and submaximal workloads (1 set of 3 repetitions at 100% PT and 2 sets of 10 repetitions at 50% PT, respectively). No significant change in PT was observed in post-stroke and healthy subjects. Force steadiness during knee extension (~25-35%, P < 0.001) and flexion (~22-33%, P < 0.001) improved after tDCS compared to the sham condition in post-stroke patients, but improved only during knee extension (~13-27%, P < 0.001) in healthy controls. These results suggest that tDCS may improve force steadiness, but not PT in post-stroke hemiparetic patients, which might be relevant in the context of motor rehabilitation programs. PMID:27601988

  15. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    Energy Technology Data Exchange (ETDEWEB)

    Vuckovic, V.; Vukosavic, S. (Electrical Engineering Inst. Nikola Tesla, Viktora Igoa 3, Belgrade, 11000 (Yugoslavia))

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  16. Two-way shape memory effect and alternating current driving characteristics of a TiNi alloy spring

    Institute of Scientific and Technical Information of China (English)

    WANG Zhiguo; ZU Xiaotao

    2004-01-01

    Two-way shape memory effect (TWSME) was induced into the TiNi shape memory alloys (SMAs) spring by thermomechanical training after annealing treatment, which has promising application in micro-actuating fields. The TWSME spring can contract upon heating and extend upon cooling. The results show that there is an increase of the recovery ratio up to a maximum TWSME of 45%. During the training procedure, transformation temperatures and hysteresis were measured by different scanning calorimetry (DSC). The results show that As (reverse transformation start temperature) and Af (revere transformation finish temperature) shift to lower temperature after training. The intervals of Af-As and Ms-Mr (Ms and Mf are the martensite start and finish temperatures, respectively) increase and the heat of transformation decreases after training. The electrothermal driving characteristics of the TWSME springs were also investigated with alternating current density of 3.2-14.7 A/mm2. It is found that the time response and the maximum contraction ratio greatly depend on the magnitude of the electrical current density.

  17. Aneurysm Sac Pressure Measurement with Minimally Invasive Implantable Pressure Sensors: An Alternative to Current Surveillance Regimes after EVAR?

    International Nuclear Information System (INIS)

    Current protocols for surveillance after endovascular repair (EVAR) of abdominal aortic aneurysms are mostly based on costly and time-consuming imaging procedures and aim to detect adverse events such as graft migration, endoleaks or aneurysm sac enlargement. These imaging procedures are either associated with radiation exposure to the patients or may be harmful to the patient due to the use of iodine- or gadolinium-containing contrast agents. Furthermore the advantages of EVAR in the short term might be negated by the necessity for endograft surveillance over years. Thus, alternative modalities for follow-up are being investigated. One of these technologies provides pressure information directly from the aneurysm sac. This noninvasive, telemetric pressure sensing was tested in vitro as well as in first clinical trials and was able to identify successful aneurysm exclusion after EVAR. The telemetric pressure sensors showed a promising efficacy and accuracy in detecting type I and type III endoleaks and will help to clarify the clinical relevance of type II endoleaks. This article provides an overview of the in vitro sensors investigated as well as the first clinical trials and the sensors' potential to change the current endograft surveillance regimes

  18. A novel induction motor starting method using superconduction

    International Nuclear Information System (INIS)

    Highlights: • Alternative method for starting up induction motor. • Based on using a high-temperature superconductor. • A prototype of the limiter was constructed with a 2G-YBCO tape. • Prototype was tested with a 55-kW industrial induction motor in a 440-V/60-Hz. • Offers reduced current waveform distortion compared to the soft starter method. - Abstract: In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method

  19. A novel induction motor starting method using superconduction

    Energy Technology Data Exchange (ETDEWEB)

    Silva, F.B.B., E-mail: flaviobarcelos@ifes.edu.br [Ifes – Federal Institute of Espírito Santo, Dept. of Industrial Automation, Serra, ES 29173087 (Brazil); UFES – Federal University of Espírito Santo, Dept. of Electrical Engineering, Vitória, ES (Brazil); Orlando, M.T.D. [UFES – Federal University of Espírito Santo, Dept. of Physics, Vitória, ES (Brazil); Fardin, J.F.; Simonetti, D.S. [UFES – Federal University of Espírito Santo, Dept. of Electrical Engineering, Vitória, ES (Brazil); Baldan, C.A. [EEL/USP – Engineering School from Lorena/University of São Paulo, SP (Brazil)

    2014-12-15

    Highlights: • Alternative method for starting up induction motor. • Based on using a high-temperature superconductor. • A prototype of the limiter was constructed with a 2G-YBCO tape. • Prototype was tested with a 55-kW industrial induction motor in a 440-V/60-Hz. • Offers reduced current waveform distortion compared to the soft starter method. - Abstract: In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method.

  20. Nonlinear Differential Geometry Method and Its Application in Induction Motor Decoupling Control

    Directory of Open Access Journals (Sweden)

    Linyuan Fan

    2016-05-01

    Full Text Available An alternating current induction motor is a nonlinear, multi-variable, and strong-coupled system that is difficult to control. To address this problem, a novel control strategy based on nonlinear differential geometry theory was proposed. First, a five-order affine mathematical model for an alternating current induction motor was provided. Then, the feedback linearization method was used to realize decoupling and full linearization of the system model. Moreover, a general and simplified control law was adopted to facilitate practical applications. Finally, a controller was designed using the pole assignment method. Simulation results show that the proposed method can decouple the system model into two independent subsystems, and that the closed-loop system exhibits good dynamic and static performances. The proposed decoupling control method is useful to reduce the system complexity of an induction motor and to improve its control performance, thereby providing a new and feasible dynamic decoupling control for an alternating current induction motor.

  1. Unusual dc electric fields induced by a high frequency alternating current in superconducting Nb films under a perpendicular magnetic field

    Science.gov (United States)

    Aliev, F. G.; Levanyuk, A. P.; Villar, R.; Sierra, J. F.; Pryadun, V. V.; Awad, A.; Moshchalkov, V. V.

    2009-06-01

    We report a systematic study of dc electric fields produced by sinusoidal high frequency ac currents in Nb superconducting films subject to a constant magnetic field perpendicular to the film plane. At frequencies in the 100 kHz to MHz range appears a new rectification effect which has not been previously observed at lower frequencies. We have observed the dc electric field generated in this regime in films without intentionally created anisotropic pinning centres, i.e. plain films, both in strip geometry as in cross-shape geometry, and also in films with symmetric periodic pinning centres. The electric field appears in both directions along and transverse to the alternating current and is essentially different at opposite film sides. It depends strongly on the intensity of the magnetic field and may exceed by nearly an order of magnitude the rectified electric fields recently reported at lower frequencies (few kHz) in systems with artificially induced anisotropic vortex pinning. The effect has a non-monotonic dependence on the drive current frequency, being maximum around a few 100 kHz to MHz, and shows a complicated temperature dependence. It is found to be different in long strips and cross shape samples. In the case of films with symmetric periodic pinning centres the rectified voltage shows a lower magnitude than in plain films, and shows an interesting structure when the applied magnetic field crosses the matching fields. We are only able to put forward tentative ideas to explain this phenomenon, which irrespective of its explanation should be taken into account in experimental studies of rectification effects in superconductors.

  2. Interactive Bio-feedback Therapy Using Hybrid Assistive Limbs for Motor Recovery after Stroke: Current Practice and Future Perspectives

    Science.gov (United States)

    MORISHITA, Takashi; INOUE, Tooru

    2016-01-01

    Interactive bio-feedback (iBF) was initially developed for the rehabilitation of motor function in patients with neurological disorders, and subsequently yielded the development of the hybrid assistive limb (HAL). Here, we provide a review of the theory underlying HAL treatment as well as our clinical experience and recommendations for future clinical studies using HAL in acute stroke patients. We performed a PubMed-based literature search, a retrospective data review of our acute stroke case series, and included a sample case report of our findings. Given past animal studies and functional imaging results, iBF therapy using the HAL in the acute phase of stroke seems an appropriate approach for preventing learned non-use and interhemispheric excitation imbalances. iBF therapy may furthermore promote appropriate neuronal network reorganization. Based on experiences in our stroke center, HAL rehabilitation is a safe and effective treatment modality for recovering motor impairments after acute stroke, and allows the design of tailored rehabilitation programs for individual patients. iBF therapy through the HAL system seems to be an effective and promising approach to stroke rehabilitation; however, the superiority of this treatment to conventional rehabilitation remains unclear. Further clinical studies are warranted. Additionally, the formation of a patient registry will permit a meta-analysis of HAL cases and address the problems associated with a controlled trial (e.g., the heterogeneity of an acute stroke cohort). The development of robotic engineering will improve the efficacy of HAL rehabilitation and has the potential to standardize patient rehabilitation practice. PMID:27616320

  3. Analysis of Input Currents in «Frequency Converter - Induction Motor» System under Asymmetry of Mains Voltage

    Directory of Open Access Journals (Sweden)

    B. I. Firago

    2006-01-01

    Full Text Available The influence of modem firequency converters with uncontrolled rectifiers on the supply network is investigated in this paper. The developed mathematical model permits us to analyze rectifier input currents with symmetrical and asymmetrical supply networks and in discontinuous operational mode. Results of modeling in case of asymmetrical supply network are shown in the form of mains current curves and current spectrum of one phase.

  4. Evidence for inhibitory effects of flupirtine, a centrally acting analgesic, on delayed rectifier k(+) currents in motor neuron-like cells.

    Science.gov (United States)

    Wu, Sheng-Nan; Hsu, Ming-Chun; Liao, Yu-Kai; Wu, Fang-Tzu; Jong, Yuh-Jyh; Lo, Yi-Ching

    2012-01-01

    Flupirtine (Flu), a triaminopyridine derivative, is a centrally acting, non-opiate analgesic agent. In this study, effects of Flu on K(+) currents were explored in two types of motor neuron-like cells. Cell exposure to Flu decreased the amplitude of delayed rectifier K(+) current (I(K(DR))) with a concomitant raise in current inactivation in NSC-34 neuronal cells. The dissociation constant for Flu-mediated increase of I(K(DR)) inactivation rate was about 9.8 μM. Neither linopirdine (10 μM), NMDA (30 μM), nor gabazine (10 μM) reversed Flu-induced changes in I(K(DR)) inactivation. Addition of Flu shifted the inactivation curve of I(K(DR)) to a hyperpolarized potential. Cumulative inactivation for I(K(DR)) was elevated in the presence of this compound. Flu increased the amplitude of M-type K(+) current (I(K(M))) and produced a leftward shift in the activation curve of I(K(M)). In another neuronal cells (NG108-15), Flu reduced I(K(DR)) amplitude and enhanced the inactivation rate of I(K(DR)). The results suggest that Flu acts as an open-channel blocker of delayed-rectifier K(+) channels in motor neurons. Flu-induced block of I(K(DR)) is unlinked to binding to NMDA or GABA receptors and the effects of this agent on K(+) channels are not limited to its action on M-type K(+) channels. PMID:22888361

  5. Transcranial alternating current stimulation (tACS increases risk taking behavior in the Balloon Analogue Risk Task

    Directory of Open Access Journals (Sweden)

    Tal eSela

    2012-02-01

    Full Text Available The process of evaluating risks and benefits involves a complex neural network that includes the dorsolateral prefrontal cortex (DLPFC. It has been proposed that in conflict and reward situations, theta-band (4–8 Hz oscillatory activity in the frontal cortex may reflect an electrophysiological mechanism for coordinating neural networks monitoring behavior, as well as facilitating task-specific adaptive changes. The goal of the present study was to investigate the hypothesis that theta-band oscillatory balance between right and left frontal and prefrontal regions, with a predominance role to the right hemisphere, is crucial for regulatory control during decision-making under risk. In order to explore this hypothesis, we used transcranial Alternating Current Stimulation (tACS, a novel technique that provides the opportunity to explore the functional role of neuronal oscillatory activities and to establish a causal link between specific oscillations and functional lateralization in risky decision-making situations. For this aim, healthy participants were randomly allocated to one of three stimulation groups (LH stimulation / RH stimulation / Sham stimulation, with active AC stimulation delivered in a frequency-dependent manner (at 6.5 Hz; 1mA peak to-peak. During the AC stimulation, participants performed the Balloon Analog Risk Task. This experiment revealed that participants receiving LH stimulation displayed riskier decision-making style compared to sham and RH stimulation groups. However, there was no difference in decision-making behaviors between sham and RH stimulation groups. The current study extends the notion that DLPFC activity is critical for adaptive decision-making in the context of risk-taking and emphasis the role of theta-band oscillatory activity during risky decision-making situations.

  6. Alternating current characterization of nano-Pt(II) octaethylporphyrin (PtOEP) thin film as a new organic semiconductor

    Science.gov (United States)

    M, Dongol; M, M. El-Nahass; A, El-Denglawey; A, A. Abuelwafa; T, Soga

    2016-06-01

    Alternating current (AC) conductivity and dielectric properties of thermally evaporated Au/PtOEP/Au thin films are investigated each as a function of temperature (303 K–473 K) and frequency (50 Hz–5 MHz). The frequency dependence of AC conductivity follows the Jonscher universal dynamic law. The AC-activation energies are determined at different frequencies. It is found that the correlated barrier hopping (CBH) model is the dominant conduction mechanism. The variation of the frequency exponent s with temperature is analyzed in terms of the CBH model. Coulombic barrier height W m , hopping distance R ω , and the density of localized states N(E F) are valued at different frequencies. Dielectric constant ε 1(ω,T) and dielectric loss ε 2(ω,T) are discussed in terms of the dielectric polarization process. The dielectric modulus shows the non-Debye relaxation in the material. The extracted relaxation time by using the imaginary part of modulus (M″) is found to follow the Arrhenius law.

  7. Optimizing the internal electric field distribution of alternating current driven organic light-emitting devices for a reduced operating voltage

    Science.gov (United States)

    Fröbel, Markus; Hofmann, Simone; Leo, Karl; Gather, Malte C.

    2014-02-01

    The influence of the thickness of the insulating layer and the intrinsic organic layer on the driving voltage of p-i-n based alternating current driven organic light-emitting devices (AC-OLEDs) is investigated. A three-capacitor model is employed to predict the basic behavior of the devices, and good agreement with the experimental values is found. The proposed charge regeneration mechanism based on Zener tunneling is studied in terms of field strength across the intrinsic organic layers. A remarkable consistency between the measured field strength at the onset point of light emission (3-3.1 MV/cm) and the theoretically predicted breakdown field strength of around 3 MV/cm is obtained. The latter value represents the field required for Zener tunneling in wide band gap organic materials according to Fowler-Nordheim theory. AC-OLEDs with optimized thickness of the insulating and intrinsic layers show a reduction in the driving voltage required to reach a luminance of 1000 cd/m2 of up to 23% (8.9 V) and a corresponding 20% increase in luminous efficacy.

  8. Alternating current calorimeter for specific heat capacity measurements at temperatures below 10 K and pressures up to 10 GPa.

    Science.gov (United States)

    Umeo, Kazunori

    2016-06-01

    A developed alternating current calorimeter for measuring the absolute value of specific heat C of a very small sample under a pressure up to 10 GPa and low temperature below 10 K is described. A Bridgman anvil cell made of tungsten carbide with a top diameter of 3 mm is used. A hollow at the top prevents expansion of the sample space over the anvil top. Two chip resistors, which act as a thermometer and a heater, are mounted on the outer part of a copper-beryllium gasket with a frying pan-like shape. Thus, the thermometer is not pressurized. In order to isolate the gasket from the anvil thermally, diamond powder with a grain size of 0.25 μm is placed on the anvil top. Two jumps of C at the superconducting transitions of Pb (3.3 mg) and In (5.0 mg) are observed under various pressures up to 9 GPa, as clearly as those at the ambient pressure. PMID:27370464

  9. Enhancing Protein Capture Using a Combination of Nanoyeast Single-Chain Fragment Affinity Reagents and Alternating Current Electrohydrodynamic Forces.

    Science.gov (United States)

    Vaidyanathan, Ramanathan; Rauf, Sakandar; Grewal, Yadveer S; Spadafora, Lauren J; Shiddiky, Muhammad J A; Cangelosi, Gerard A; Trau, Matt

    2015-12-01

    New high-performance detection technologies and more robust protein capture agents can be combined to both rapidly and specifically capture and detect protein biomarkers associated with disease in complex biological samples. Here we demonstrate the use of recently developed recombinant affinity reagents, namely nanoyeast-scFv, in combination with alternating current electrohydrodynamic (ac-EHD)-induced shear forces, to enhance capture performance during protein biomarker analysis. The use of ac-EHD significantly improves fluid transport across the capture domain, resulting in enhanced sensor-target interaction and simultaneous displacement of nonspecific molecules from the electrode surface. We demonstrate this simple proof-of-concept approach for the capture and detection of Entamoeba histolytica antigens from disinfected stool, within a span of 5 min using an ac-EHD microfluidic device. Under an ac-EHD field, antigens were captured on a nanoyeast-scFv immobilized device and subsequently detected using a quantum dot conjugated antibody. This immunosensor specifically detected antigen in disinfected stool with low background noise at concentrations down to 58.8 fM with an interassay reproducibility (%RSD of n = 3) gold electrodes in disinfected stool. We predict this rapid and sensitive approach using these stable affinity reagents may offer a new methodology to detect protein disease biomarkers from biological matrices. PMID:26551436

  10. Comparison of atmospheric air plasmas excited by high-voltage nanosecond pulsed discharge and sinusoidal alternating current discharge

    Science.gov (United States)

    Zhang, Shuai; Wang, Wen-chun; Jiang, Peng-chao; Yang, De-zheng; Jia, Li; Wang, Sen

    2013-10-01

    In this paper, atmospheric pressure air discharge plasma in quartz tube is excited by 15 ns high-voltage nanosecond pulsed discharge (HVNPD) and sinusoidal alternating current discharge (SACD), respectively, and a comparison study of these two kinds of discharges is made through visual imaging, electrical characterization, optical detection of active species, and plasma gas temperature. The peak voltage of the power supplies is kept at 16 kV while the pulse repetition rate of nanosecond pulse power supply is 100 Hz, and the frequency of sinusoidal power supply is 10 kHz. Results show that the HVNPD is uniform while the SACD presents filamentary mode. For exciting the same cycles of discharge, the average energy consumption in HVNPD is about 1/13 of the SACD. However, the chemical active species generated by the HVNPD is about 2-9 times than that excited by the SACD. Meanwhile, the rotational and vibrational temperatures have been obtained via fitting the simulated spectrum of N2 (C3Πu → B3Πg, 0-2) with the measured one, and the results show that the plasma gas temperature in the HVNPD remains close to room temperature whereas the plasma gas temperature in the SACD is about 200 K higher than that in HVNPD in the initial phase and continually increases as discharge exposure time goes on.

  11. 一个新的适用于无刷直流电机驱动的单电流传感器技术%A Novel Current Sensor Technique for Brushless DC Motor Drives

    Institute of Scientific and Technical Information of China (English)

    谭徽; 江建中; 汪信尧; 王勇

    2000-01-01

    The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.

  12. Compound current control for aerospace fuel pump motor%航空油泵电机复合电流控制

    Institute of Scientific and Technical Information of China (English)

    匡敏驰; 朱纪洪; 吉敬华

    2014-01-01

    考虑电枢反应中磁饱和现象、电机各相间互感以及功率管的非线性特性等因素的影响,为提升电流环性能,提出了一种新型的永磁同步电机复合电流控制方法.该方法中控制器由相电流畸变纠正控制器和功率角补偿控制器组成.相电流畸变控制器采用P控制配合电流前馈实现,能够较好地对相电流畸变进行纠正.针对负载变化时功率角变化较大的问题,专门设计了功率角补偿控制器,可以通过稳定快速地检测内功率因数角自动进行功率角补偿.实验结果验证了该方法的有效性,表明该方法可以在高转速、大电流、高动态的情况下稳定可靠地对航空油泵电机进行控制.%A compound current control method was developed for permanent-magnet synchronous motors to improve the current control by considering the magnetic saturation,mutual inductance and nonlinear characteristics of the inverters.The controller is a current distortion correcting controller with a power angle compensating controller.The phase current distortion correcting controller uses P control with current feed forward,which can correct phase current distortions.Since the power angle changes with the load,the control method includes a power angle compensating controller which automatically compensate for changes in the power angle by quickly detecting the internal power-factor angle.Tests verify the effectiveness of this controller which gives a stable,reliable control for a high speed,rapidly varying aerospace fuel pump motor that draws large currents.

  13. Electrical motor/generator drive apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

    Su, Gui Jia

    2013-02-12

    The present disclosure includes electrical motor/generator drive systems and methods that significantly reduce inverter direct-current (DC) bus ripple currents and thus the volume and cost of a capacitor. The drive methodology is based on a segmented drive system that does not add switches or passive components but involves reconfiguring inverter switches and motor stator winding connections in a way that allows the formation of multiple, independent drive units and the use of simple alternated switching and optimized Pulse Width Modulation (PWM) schemes to eliminate or significantly reduce the capacitor ripple current.

  14. Online Monitoring of Induction Motors

    Energy Technology Data Exchange (ETDEWEB)

    McJunkin, Timothy R. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Lybeck, Nancy Jean [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-01-01

    The online monitoring of active components project, under the Advanced Instrumentation, Information, and Control Technologies Pathway of the Light Water Reactor Sustainability Program, researched diagnostic and prognostic models for alternating current induction motors (IM). Idaho National Laboratory (INL) worked with the Electric Power Research Institute (EPRI) to augment and revise the fault signatures previously implemented in the Asset Fault Signature Database of EPRI’s Fleet Wide Prognostic and Health Management (FW PHM) Suite software. Induction Motor diagnostic models were researched using the experimental data collected by Idaho State University. Prognostic models were explored in the set of literature and through a limited experiment with 40HP to seek the Remaining Useful Life Database of the FW PHM Suite.

  15. The mathematical model of the motor drive current based on considerable measure%可观测量的电动机驱动电流建模

    Institute of Scientific and Technical Information of China (English)

    黄飞超; 陈明明; 杨戍

    2012-01-01

    检验汽车行车制动器设计的优劣,需要得到电动机驱动电流与时间之间的精确关系。因为制动器性能的复杂性,驱动电流与时间之间的精确关系很难得到。基于模拟实验台,由能量等效转化的方法,将能量转化为可观测的转速以及对于转动物体来说恒定不变的转动惯量,建立了电动机驱动电流依赖于可观测量的数学模型。%In order to test the merits of the design on brakes, the precise relationship between the motor drive current and time is necessary. Because of the complexity of the Braking performance, it' s too difficult to get the precise relationship. On the basis of Energy Equivalent Conversion, this essay is to get the mathematical model based on the quantities of the motor, such as rotate speed and rotary inertia which is measurable or constant.

  16. Advanced Motors

    Energy Technology Data Exchange (ETDEWEB)

    Knoth, Edward A.; Chelluri, Bhanumathi; Schumaker, Edward J.

    2012-12-14

    Project Summary Transportation energy usage is predicted to increase substantially by 2020. Hybrid vehicles and fuel cell powered vehicles are destined to become more prominent as fuel prices rise with the demand. Hybrid and fuel cell vehicle platforms are both dependent on high performance electric motors. Electric motors for transportation duty will require sizeable low-speed torque to accelerate the vehicle. As motor speed increases, the torque requirement decreases which results in a nearly constant power motor output. Interior permanent magnet synchronous motors (IPMSM) are well suited for this duty. , , These rotor geometries are configured in straight lines and semi circular arc shapes. These designs are of limited configurations because of the lack of availability of permanent magnets of any other shapes at present. We propose to fabricate rotors via a novel processing approach where we start with magnet powders and compact them into a net shape rotor in a single step. Using this approach, widely different rotor designs can be implemented for efficiency. The current limitation on magnet shape and thickness will be eliminated. This is accomplished by co-filling magnet and soft iron powders at specified locations in intricate shapes using specially designed dies and automatic powder filling station. The process fundamentals for accomplishing occurred under a previous Applied Technology Program titled, “Motors and Generators for the 21st Century”. New efficient motor designs that are not currently possible (or cost prohibitive) can be accomplished by this approach. Such an approach to

  17. 无刷直流电动机不导通相电流分析%Analysis of Floating Phase Current in Brushless DC Motor

    Institute of Scientific and Technical Information of China (English)

    王璞; 解恩; 翟猛

    2012-01-01

    分析了无刷直流电动机在三相六状态及不同的PWM方式下,绕组续流期间不导通相电流,并且指出各有不同.对常用的各种PWM方式通过原理分析及数学推导,得出不导通相电流存在的时段和幅值趋势.并通过实验测试,验证了分析结果.%The floating phase current during the free-wheeling and the difference of the brushless DC motor operating in three-phase-six-states and different PWM modes were analysed. The conclusion of existing time and amplitude trend were achieved by theory analysis and mathematical deduction of common PWM modes. The result was verified through the experiment test.

  18. 航空油泵电机的相电流畸变纠正控制%Phase current distortion correction control for aerospace fuel pump motor

    Institute of Scientific and Technical Information of China (English)

    匡敏驰; 朱纪洪; 吉敬华

    2015-01-01

    In order to improve current performance, a new control method is proposed to correct the distortion of phase current, in which the magnetic saturation and the nonlinear characteristic of inverters are considered. The amplitude fluctuation is eliminated by using feed forward current amplitude compensation. Meanwhile, based on iteration convergence control, the phase current is compulsorily corrected to a standard sinusoidal shape. Then, the problem of the phase current distortion is successfully solved. The experimental results show that the amplitude of phase current is reduced effectively, and the efficiency of motor system is improved.%考虑电枢反应中磁饱和现象和驱动器功率管非线性特性等因素的影响,为了解决航空油泵电机相电流谐波含量大、畸变较为严重的问题,提出一种新型的相电流畸变纠正控制方法. 该方法通过电流前馈幅值补偿能够基本消除各周期相电流幅值的波动,并通过迭代收敛控制,最终将相电流强制纠正为标准正弦波,从而解决了相电流畸变的难题.实验结果表明,所提出的相电流畸变纠正控制方法可以有效减少相电流幅值,提高电机系统的效率.

  19. Modelling of the steady state thermal behaviour of a permanent magnet direct current motor with commutator. 3D finite elements study

    Science.gov (United States)

    Bernard, R.; Glises, R.; Chamagne, D.; Cuchet, D.; Kauffmann, J. M.

    1999-08-01

    The aim of this work concerns the development and the validation of a thermal steady state model applied to a permanent magnet direct current motor with commutator. The rated power of the machine is 120 W. Design has been realized thanks to the thermal modulus of the computation software with the finite element method Flux3D. It is shown in this work how it is possible to use only the heat equation to simulate the thermal behaviour of the motor. It implies calculating of new fluid conductivities (considering also all thermal modes) by comparison of calculated and experimental temperatures. To realize these 3D modelizations, it is necessary to know and to locate all the losses of the motor which are considered as thermal sources. The experimental temperatures are given by 40 chromel-alumel thermocouples of 100 μm diameter located in the rotor and the stator of the machine. Numerical computations use Dirichlet boundary layer conditions given by an IR camera. Ce travail concerne le développement et la validation d'un modèle de simulation du comportement thermique tridimensionnel en régime permanent d'un moteur électrique de 120 watt à courant continu, à aimants permanents et à collecteur. Le logiciel est développé à partir du code de calculs par éléments finis Flux3D. L'équation de la chaleur modélise l'ensemble des transferts thermiques du moteur. Cela nécessite de recaler certains paramètres fluides par comparaison des températures simulées et expérimentales. Une séparation détaillée des différentes pertes est nécessaire pour obtenir une bonne précision finale. Un banc d'essais thermiques permet d'obtenir à l'aide de 40 thermocouples (chromel-alumel de 100 μm de diamètre) les températures au stator et au rotor. Une caméra thermographique infrarouge donne les conditions aux limites de Dirichlet nécessaires à la modélisation.

  20. Investigation of parameters of the three phase high-voltage alternating current plasma generator with power up to 100 kW working on steam

    Science.gov (United States)

    Rutberg, Ph G.; Lukyanov, S. A.; Kiselev, A. A.; Kuschev, S. A.; Nakonechny, Gh V.; Nikonov, A. V.; Popov, S. D.; Serba, E. O.; Spodobin, V. A.; Surov, A. V.

    2011-01-01

    The paper presents the results of experimental investigation of parameters of the three-phase high voltage alternating current plasma generator with power up to 100 kW operating on steam with gas protection of the electrodes. Researches were carried out over a range of arc current from 25 to 50 A and range of steam consumption of 3-5 g/s. Current-voltage and volt consumable characteristics, operation oscillograms and dependence of power versus the flow rate of steam and protective gas are presented.

  1. Palm oil production in Peruvian Amazon Basin. A case study of current effects and emerging localized alternatives in Loreto district

    OpenAIRE

    Jensen, Charlotte Bratberget

    2015-01-01

    An analysis of palm oil production in the Peruvian Amazon basin was carried out in a systemic way, as part of a whole, with its complexities. With an agroecological perspective, the social, ecological and economic effects of this production are discussed. Additionally, alternatives that could better fulfil the necessities of farmers were explored. The oil palm, Elaeis guineensis, originally from West Africa, is a common plant in an enormous industry that is extensive in South East Asia, ma...

  2. Transcranial Direct Current Stimulation over the Medial Prefrontal Cortex and Left Primary Motor Cortex (mPFC-lPMC) Affects Subjective Beauty but Not Ugliness.

    Science.gov (United States)

    Nakamura, Koyo; Kawabata, Hideaki

    2015-01-01

    Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC) and the left primary motor cortex (lPMC) correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS) to examine whether non-invasive brain stimulation modulates two types of esthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions. PMID:26696865

  3. Transcranial direct current stimulation over the medial prefrontal cortex and left primary motor cortex (mPFC-lPMC affects subjective beauty but not ugliness

    Directory of Open Access Journals (Sweden)

    Koyo eNakamura

    2015-12-01

    Full Text Available Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC and the left primary motor cortex (lPMC correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS to examine whether noninvasive brain stimulation modulates two types of aesthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions.

  4. Transcranial Direct Current Stimulation over the Medial Prefrontal Cortex and Left Primary Motor Cortex (mPFC-lPMC) Affects Subjective Beauty but Not Ugliness.

    Science.gov (United States)

    Nakamura, Koyo; Kawabata, Hideaki

    2015-01-01

    Neuroaesthetics has been searching for the neural bases of the subjective experience of beauty. It has been demonstrated that neural activities in the medial prefrontal cortex (mPFC) and the left primary motor cortex (lPMC) correlate with the subjective experience of beauty. Although beauty and ugliness seem to be semantically and conceptually opposite, it is still unknown whether these two evaluations represent extreme opposites in unitary or bivariate dimensions. In this study, we applied transcranial direct current stimulation (tDCS) to examine whether non-invasive brain stimulation modulates two types of esthetic evaluation; evaluating beauty and ugliness. Participants rated the subjective beauty and ugliness of abstract paintings before and after the application of tDCS. Application of cathodal tDCS over the mPFC with anode electrode over the lPMC, which induced temporal inhibition of neural excitability of the mPFC, led to a decrease in beauty ratings but not ugliness ratings. There were no changes in ratings of both beauty and ugliness when applying anodal tDCS or sham stimulation over the mPFC. Results from our experiment indicate that the mPFC and the lPMC have a causal role in generating the subjective experience of beauty, with beauty and ugliness evaluations constituting two distinct dimensions.

  5. Effects of left primary motor and dorsolateral prefrontal cortex transcranial direct current stimulation on laser-evoked potentials in migraine patients and normal subjects.

    Science.gov (United States)

    Vecchio, Eleonora; Ricci, Katia; Montemurno, Anna; Delussi, Marianna; Invitto, Sara; de Tommaso, Marina

    2016-07-28

    Migraine is characterized by an altered cortical excitability. Because transcranial direct current stimulation (tDCS) can change brain activity noninvasively, it is possible to hypothesize its efficacy in modulating pain in migraine. In this study, we compared the effects of tDCS of the left primary motor cortex (M1) and left dorsolateral prefrontal cortex (DLPFC) both on subjective pain and on evoked responses induced by laser stimulation (LEPs). Thirty-two patients and sixteen controls were randomized to receive sham stimulation and real tDCS with the anode centered over M1 or DLPFC. Laser Evoked potentials were recorded in basal, sham and tDCS conditions. We did not find significant acute changes in LEPs parameters and pain perception among subjects who received tDCS of both M1 and DLPFC. After DLPFC tDCS, we observed a significant increase of N2-P2 component habituation in migraine patients while M1 stimulation reduced it. These findings may suggest a modulation of abnormal pain processing induced by DLPFC and M1 anodal tDCS and outline the need for future investigations exploring the possible neuronal plasticity changes supporting the clinical effect on migraine. PMID:27208831

  6. Cryogenic Electric Motor Tested

    Science.gov (United States)

    Brown, Gerald V.

    2004-01-01

    Technology for pollution-free "electric flight" is being evaluated in a number of NASA Glenn Research Center programs. One approach is to drive propulsive fans or propellers with electric motors powered by fuel cells running on hydrogen. For large transport aircraft, conventional electric motors are far too heavy to be feasible. However, since hydrogen fuel would almost surely be carried as liquid, a propulsive electric motor could be cooled to near liquid hydrogen temperature (-423 F) by using the fuel for cooling before it goes to the fuel cells. Motor windings could be either superconducting or high purity normal copper or aluminum. The electrical resistance of pure metals can drop to 1/100th or less of their room-temperature resistance at liquid hydrogen temperature. In either case, super or normal, much higher current density is possible in motor windings. This leads to more compact motors that are projected to produce 20 hp/lb or more in large sizes, in comparison to on the order of 2 hp/lb for large conventional motors. High power density is the major goal. To support cryogenic motor development, we have designed and built in-house a small motor (7-in. outside diameter) for operation in liquid nitrogen.

  7. High Voltage Resistive Divider Based on Cast Microwire in Glass Insulation on 6–24 kV Alternating Current of Commercial Frequency.

    Directory of Open Access Journals (Sweden)

    Juravleov A.

    2008-12-01

    Full Text Available It is presented the analysis and description of the construction of the high voltage resistive divider on the base of cast microwire in glass insulation on 6–24 kV alternating current of commercial frequency. It is presented the procedure of compensation of frequency error during the process of fabrication of divides and results of tests of the sample model of the divider as well.

  8. Motor variability in occupational health and performance.

    Science.gov (United States)

    Srinivasan, Divya; Mathiassen, Svend Erik

    2012-12-01

    Several recent reviews have reported that 'repetitive movements' constitute a risk factor for occupational musculoskeletal disorders in the neck, shoulder and arm regions. More variation in biomechanical exposure is often suggested as an effective intervention in such settings. Since increasing variation using extrinsic methods like job rotation may not always be possible in an industrial context, the intrinsic variability of the motor system may offer an alternative opportunity to increase variation. Motor variability refers to the natural variation in postures, movements and muscle activity observed to different extents in all tasks. The current review discusses research appearing in motor control, sports sciences and occupational biomechanics literature to answer whether motor variability is important to consider in an occupational context, and if yes, whether it can be manipulated by training the worker or changing the working conditions so as to increase biomechanical variation without jeopardizing production. The review concludes that motor variability is, indeed, a relevant issue in occupational health and performance and suggests a number of key issues for further research. PMID:22954427

  9. Alternatives and selection of an electrical motor for the autonomous hybrid drive system; Alternativen und Auswahl eines Elektromotors fuer den Autarken Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Krasser, B.; Lorenzen, H.W.; Schmid, M.

    1994-12-31

    Equipping a vehicle with a hybrid drive system always involves additional components to be installed. These components will have to be specifically light of weight with a view to total vehicle weight increase. In the electrical motor, weight savings may be achieved by an appropriate selection of motor concept and speed. The weight of electronic parts is largely determined by the weight of the associated heat dissipation systems. The different drive trains will be studied for their efficiency and operating properties in various test cycles on test stand which is being set up. This test rig will have a high-precision output analyzer which will be accurate if samples are static-converter-fed. Computer simulations will be used for optimization. (orig./HW) [Deutsch] Die Ausruestung eines Fahrzeugs mit einem Hybridantrieb bedingt immer zusaetzliche Komponenten. Diese Komponenten muessen im Hinblick auf eine moeglichst geringe Zunahme des Gesamtgewichts besonders leicht sein. Die Gewichtsreduzierung beim Elektromotor laesst sich durch die Wahl des Motorkonzepts und der Drehzahl beeinflussen. Bei der Leistungselektronik wird der groesste Anteil des Gewichts durch die Einrichtungen zur Waemeabfuhr verursacht. Die verschiedenen Antriebsstraenge sollen auf einem im Aufbau befindlichen Pruefstand hinsichtlich Wirkungsgrad und Betriebseigenschaften bei unterschiedlichen Testzyklen untersucht werden. Am Pruefstand wird ein hochgenauer Leistungsanalysator eingesetzt, der auch bei Stromrichterspeisung der Prueflinge praezise arbeitet. Als Hilfe zur Optimierung werden Computersimulationen ausgefuehrt. (orig./HW)

  10. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kajikawa, K., E-mail: kajikawa@sc.kyushu-u.ac.j [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Funaki, K. [Research Institute of Superconductor Science and Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395 (Japan); Shikimachi, K.; Hirano, N.; Nagaya, S. [Chubu Electric Power Co., Inc., 20-1 Kitasekiyama, Ohdaka-cho, Midori-ku, Nagoya 459-8522 (Japan)

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean's critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  11. Numerical and theoretical evaluations of AC losses for single and infinite numbers of superconductor strips with direct and alternating transport currents in external AC magnetic field

    Science.gov (United States)

    Kajikawa, K.; Funaki, K.; Shikimachi, K.; Hirano, N.; Nagaya, S.

    2010-11-01

    AC losses in a superconductor strip are numerically evaluated by means of a finite element method formulated with a current vector potential. The expressions of AC losses in an infinite slab that corresponds to a simple model of infinitely stacked strips are also derived theoretically. It is assumed that the voltage-current characteristics of the superconductors are represented by Bean’s critical state model. The typical operation pattern of a Superconducting Magnetic Energy Storage (SMES) coil with direct and alternating transport currents in an external AC magnetic field is taken into account as the electromagnetic environment for both the single strip and the infinite slab. By using the obtained results of AC losses, the influences of the transport currents on the total losses are discussed quantitatively.

  12. Alternating current losses of a 10 metre long low loss superconducting cable conductor determined from phase sensitive measurements

    DEFF Research Database (Denmark)

    Olsen, Søren Krüger; Kühle (fratrådt), Anders Van Der Aa; Træholt, Chresten;

    1999-01-01

    voltage. The 1 mu V cm(-1) critical current of the conductor was 3240 A at 77 K. At an rms current of 2 kA (50 Hz) the ac loss was derived to be 0.6 +/- 0.15 W m(-1). This is, to the best of our knowledge, the lowest value of ac loss of a high temperature superconducting cable conductor reported so far...

  13. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    Directory of Open Access Journals (Sweden)

    Paolo Zamboni

    2016-01-01

    Full Text Available Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA. However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b the use of just a single CSA value in a pulsatile vessel is inaccurate; (c time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave and with the outflow (jugular venous pulse in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

  14. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse.

    Science.gov (United States)

    Zamboni, Paolo

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders.

  15. Organizing motor imageries.

    Science.gov (United States)

    Hanakawa, Takashi

    2016-03-01

    Over the last few decades, motor imagery has attracted the attention of researchers as a prototypical example of 'embodied cognition' and also as a basis for neuro-rehabilitation and brain-machine interfaces. The current definition of motor imagery is widely accepted, but it is important to note that various abilities rather than a single cognitive entity are dealt with under a single term. Here, motor imagery has been characterized based on four factors: (1) motor control, (2) explicitness, (3) sensory modalities, and (4) agency. Sorting out these factors characterizing motor imagery may explain some discrepancies and variability in the findings from previous studies and will help to optimize a study design in accordance with the purpose of each study in the future. PMID:26602980

  16. 基于DSP控制的纯电动汽车无刷直流电动机%Brushless Direct Current Motor Based on DSP Control on Pure Electric Vehicle

    Institute of Scientific and Technical Information of China (English)

    吴敏

    2011-01-01

    无刷直流电动机是一种高性能的电动机,它具有结构简单、运行可靠、维护方便、运行效率高、无励磁损耗、运行成本低和调速性能好等优点,因此,它在电动汽车上的应用与日俱增.对无刷直流电动机控制的优化是人们一直期待解决的问题。文章设计了利用TMS320LF2407DSP控制器构成的无刷直流电动机的无位置传感器控制的系统硬件和系统软件,实现了对无位置传感器无刷直流电动机的优化控制,试验证明了该方法的正确性和有效性。%Brushless direct current motor is a type of motor with high performance and many advantages, including simple structure, reliable operation, convenient maintenance, high efficiency, non-excitation loss, low cost and good performance of speed governing. Therefore, its application on electric vehicles has increased. People have been looking forward to the solution to the optimization of the control of brushless direct current motor. This paper designs the eontrolling system's hardware and software for no-position sensor on the brushless current motor with the structure of TMS320LF2407 DSP controller, which optimized the brushless current motor with no-position sensor. The test also proves the correctness and effectiveness of this method.

  17. Current State of Research at the EMAD Research Centre from „Ştefan cel Mare“ University in Connection with Actuators and Solar Motors with Solid Heating Medium

    Directory of Open Access Journals (Sweden)

    Adrian Neculai Romanescu

    2014-09-01

    Full Text Available Within the EMAD Research Center of the USV have been developed since 1996 a number of solutions in heliothermic actuators and motors area made on the basis of solid heating medium. The solutions relates to rotary actuators and motors as well as linear actuators with limited movement. Are presented the primary constructive solutions with the peculiarities and finally, the general conclusion regarding the experimentation and practical implementation.

  18. A Study of Second-Year Engineering Students' Alternative Conceptions about Electric Potential, Current Intensity and Ohm's Law

    Science.gov (United States)

    Periago, M. Cristina; Bohigas, Xavier

    2005-01-01

    The aim of this research was to evaluate and analyse second-year industrial engineering and chemical engineering students prior knowledge of conceptual aspects of "circuit theory". Specifically, we focused on the basic concepts of electric potential and current intensity and on the fundamental relationship between them as expressed by Ohm's law.…

  19. The effects of anodal transcranial direct current stimulation and patterned electrical stimulation on spinal inhibitory interneurons and motor function in patients with spinal cord injury.

    Science.gov (United States)

    Yamaguchi, Tomofumi; Fujiwara, Toshiyuki; Tsai, Yun-An; Tang, Shuen-Chang; Kawakami, Michiyuki; Mizuno, Katsuhiro; Kodama, Mitsuhiko; Masakado, Yoshihisa; Liu, Meigen

    2016-06-01

    Supraspinal excitability and sensory input may play an important role for the modulation of spinal inhibitory interneurons and functional recovery among patients with incomplete spinal cord injury (SCI). Here, we investigated the effects of anodal transcranial direct current stimulation (tDCS) combined with patterned electrical stimulation (PES) on spinal inhibitory interneurons in patients with chronic incomplete SCI and in healthy individuals. Eleven patients with incomplete SCI and ten healthy adults participated in a single-masked, sham-controlled crossover study. PES involved stimulating the common peroneal nerve with a train of ten 100 Hz pulses every 2 s for 20 min. Anodal tDCS (1 mA) was simultaneously applied to the primary motor cortex that controls the tibialis anterior muscle. We measured reciprocal inhibition and presynaptic inhibition of a soleus H-reflex by stimulating the common peroneal nerve prior to tibial nerve stimulation, which elicits the H-reflex. The inhibition was assessed before, immediately after, 10 min after and 20 min after the stimulation. Compared with baseline, simultaneous application of anodal tDCS with PES significantly increased changes in disynaptic reciprocal inhibition and long-latency presynaptic inhibition in both healthy and SCI groups for at least 20 min after the stimulation (all, p < 0.001). In patients with incomplete SCI, anodal tDCS with PES significantly increased the number of ankle movements in 10 s at 20 min after the stimulation (p = 0.004). In conclusion, anodal tDCS combined with PES could induce spinal plasticity and improve ankle movement in patients with incomplete SCI. PMID:26790423

  20. Analysis of the Alternating-current Circuits with Matlab%利用Matlab分析交流电路

    Institute of Scientific and Technical Information of China (English)

    陆朝华; 蓝海江

    2011-01-01

    探讨利用Matlab软件辅助分析交流电路的方法。以Matlab软件为辅助工具,具体分析了动态电路、正弦稳态电路及非正弦交流电路。结果表明,利用Matlab软件辅助分析交流电路问题,逻辑清晰、程序简短、结果精确。因此,Matlab软件是分析和研究电路的有效工具。%By using Matlab software,the aided analysis method of alternating-current(AC) circuits was explored.Taking Matlab software as aids,the dynamic circuit,sinusoidal steady state circuit and non-sinusoidal AC circuit were discussed.The results show that,it has such features: a clear logic,a short program and an accurate result,which analyzing the problems of AC circuits on using Matlab software.Therefore,the Matlab software is an effective tool for analyzing and researching AC circuits.

  1. Symmetric Brownian motor

    OpenAIRE

    Gomez-Marin, A.; Sancho, J. M.

    2004-01-01

    In this paper we present a model of a symmetric Brownian motor (SBM) which changes the sign of its velocity when the temperature gradient is inverted. The velocity, external work and efficiency are studied as a function of the temperatures of the baths and other relevant parameters. The motor shows a current reversal when another parameter (a phase shift) is varied. Analytical predictions and results from numerical simulations are performed and agree very well. Generic properties of this type...

  2. 儿童运动发育评定现状研究%Study on the Current Situation of Children's Motor Development Assessment

    Institute of Scientific and Technical Information of China (English)

    梁运龙; 潘华玮; 赵嘉文; 易文俊; 孙嘉惠

    2014-01-01

    Motor development assessment is an important means to early discovery abnormal development of children. This paper reviews the rating scale, evaluation mechanism, evaluation popularity of children's motor development, in order to provide the reference on rehabilitation assessment study of children's motor development.%运动发育评定是早期发现儿童异常发育的重要手段。本文从儿童运动发育评定量表、评定机构、评定普及度三个方面进行综述,以期为儿童运动发育的康复评定研究提供参考。

  3. Motor neglect.

    OpenAIRE

    Laplane, D.; Degos, J D

    1983-01-01

    Motor neglect is characterised by an underutilisation of one side, without defects of strength, reflexes or sensibility. Twenty cases of frontal, parietal and thalamic lesions causing motor neglect, but all without sensory neglect, are reported. It is proposed that the cerebral structures involved in motor neglect are the same as those for sensory neglect and for the preparation of movement. As in sensory neglect, the multiplicity of the structures concerned suggests that this interconnection...

  4. Harmonic flux penetration of superconductors in low-frequency, high-amplitude, alternating-current magnetic fields

    CERN Document Server

    Ramsbottom, H D

    1997-01-01

    A critical-state model has been used to calculate the magnetic response of a superconducting sample to an applied a.c. magnetic field. The analysis has been performed for both a cylindrical and a slab geometry and evaluated up to the tenth harmonic. It is shown that standard expressions derived using the critical-state model which relate the critical current density to the d.c. magnetic moment can be used in a.c. measurements to within an accuracy of approx 4% by replacing the term for the d.c. magnetic moment by sq root 2m sub r sub m sub s (min), where m sub r sub m sub s (min) is the minimum lossless rms magnetic moment; the apparent penetration of the field beyond the centre of the sample (i.e. an overshoot) found in flux penetration measurements is an artifact of the analysis and cannot be used as direct evidence for granularity. Flux penetration measurements on non-granular NbTi from 4.2 K up to T sub c in magnetic fields up to 10 T are presented which provide good agreement with calculations. (author)

  5. Segmented motor drive - with multi-phase induction motor

    DEFF Research Database (Denmark)

    Bendixen, Flemming Buus

    This PhD project commences in modulation of motor drives, i.e. having the advantage of reducing the number of variants and improves the system reliability at error situations. Four different motor drive topologies with modular construction as common denominator are compared on a general level....... The multi-phase motor is selected for further analysis. The project is limited to examine if increasing the number of phases can improve the characteristics for induction motor drives. In the literature it is demonstrated that torque production in a six-phase motor can be increased, if a 3rd harmonic...... current with 1/6 amplitude is added to the 1st harmonic current. This claim is verified and the optimization of the motor design is extended to, beyond the stator tooth width, also to include the inner diameter of the stator. This means that the lamination sheet is optimized according to two geometrical...

  6. Current levels and composition profiles of PBDEs and alternative flame retardants in surface sediments from the Pearl River Delta, southern China: Comparison with historical data

    International Nuclear Information System (INIS)

    Polybrominated diphenyl ethers (PBDEs) and alternative flame retardants were measured in surface sediments collected during 2009–2010 from the Pearl River Delta, southern China (a large manufacturing base for electronics/electrical products), to evaluate the influence of China's RoHS directive (adopted in 2006) on their environmental occurrence. The concentrations in sediments from different water systems ranged from 3.67 to 2520 ng/g (average of 17.1–588 ng/g) for PBDEs and from 0.22 to 5270 ng/g (average of 11.3–454 ng/g) for the alternative retardants. Although the PBDE levels have decreased significantly compared with those in sediments collected in 2002 in this region, the levels of alternative decabromodiphenyl ethane (DBDPE) have exceeded those of BDE209 (two predominant halogenated flame retardants (HFRs) in China) in the majority of sediments. This finding suggests a different contaminant pattern of HFRs in current sediments due to the replacement of the deca-BDE mixture with DBDPE in this region. In addition, sediment concentrations of discontinued PBDEs in the rural area are clearly elevated due to e-waste dismantling. The congener profiles of PBDEs in the current sediments (with more abundant lower-brominated congeners) differed substantially from those in 2002 and from the technical products, suggesting that biological or photolytic debromination of PBDEs may have occurred in the environment. - Highlights: ► PBDE levels in sediments have decreased substantially since China's RoHS directive. ► Contamination of novel DBDPE has exceeded that of deca-BDE in the PRD sediments. ► The congener profiles of PBDEs in the sediments have changed significantly. ► Significant biological or photolytic degradation of PBDEs may occur in the environment

  7. High-performance motor drives

    OpenAIRE

    Kazmierkowski, Marian P.; García Franquelo, Leopoldo; Rodríguez, José; Pérez, Marcelo; León Galván, José Ignacio

    2011-01-01

    This article reviews the present state and trends in the development of key parts of controlled induction motor drive systems: converter topologies, modulation methods, as well as control and estimation techniques. Two- and multilevel voltage-source converters, current-source converters, and direct converters are described. The main part of all the produced electric energy is used to feed electric motors, and the conversion of electrical power into mechanical power involves motors ranges from...

  8. Induction motor feedback current calculation and speed factor analysis%电压跌落时感应电动机反馈电流计算及转速影响研究

    Institute of Scientific and Technical Information of China (English)

    姜杰; 许宏; 陈贵文; 张太勤

    2014-01-01

    Large capacity induction machines have a great influence on short-circuit current level of industrial distribution network. Accurate calculation of the feedback current plays an important role in protection configuration and short-circuit current calculation. The motor speed changing during voltage drop is an important factor affecting the accuracy of feedback current calculation, regardless of the speed changing may cause error in feedback current calculation and affect the operation of protection. Using the positive and negative sequence steady-state equivalent circuit of induction motor and constant complex coefficient linear differential equations solving process, forced component and free component of stator/rotor flux linkage are solved. Then the induction motor feedback current formula in consideration of speed changing factor is deduced. Furthermore, the influence of speed on each component of the flux and feedback current is analyzed. The correctness of the proposed analysis is verified by the fifth electromagnetic transient model of induction motor in PSCAD/EMTDC simulation software.%大容量感应电动机会影响工业配网的短路电流水平,准确计算其反馈电流对系统保护配置及全网短路电流计算具有重要作用。电压跌落时电动机转速变化会影响电动机的反馈电流,不考虑转速变化可能会导致反馈电流计算结果不准确,影响保护的正确动作。利用感应电动机静态等值电路和复常系数线性微分方程组解法求解定转子磁链正负序强制分量和自由分量,进而得到电压跌落时计及转速变化的感应电动机反馈电流计算方法,并进一步探讨了转速对磁链和反馈电流各分量的影响。采用PSCAD/ EMTDC仿真软件中感应电动机的5阶动态模型仿真验证了该分析的正确性。

  9. Infant overweight is associated with delayed motor development

    Science.gov (United States)

    Slining, Meghan; Adair, Linda S.; Goldman, Barbara Davis; Borja, Judith B.; Bentley, Margaret

    2012-01-01

    Objective To examine how infant overweight and high subcutaneous fat relate to infant motor development. Study design Participants are from the Infant Care, Feeding, and Risk of Obesity Project, a prospective, longitudinal study of low-income African American mother-infant dyads assessed from 3 -18 months of age (836 observations on 217 infants). Exposures were overweight (weight-for-length z-score ≥90th percentile of 2000 CDC/NCHS growth reference) and high subcutaneous fat (sum of three skinfold measurements >90th percentile of our sample). Motor development was assessed using Bayley Scales of Infant Development-II. Developmental delay was characterized as a standardized Psychomotor Development Index score <85. Longitudinal models estimated developmental outcomes as functions of time-varying overweight and subcutaneous fat, controlling for age and sex. Alternate models tested concurrent and lagged relationships (prior weight or subcutaneous fat predicting current motor development). Results Motor delay was 1.80 times as likely in overweight compared with non-overweight infants (95% CI:1.09, 2.97), and 2.32 times as likely in infants with high subcutaneous fat compared with lower subcutaneous fat (95% CI:1.26, 4.29). High subcutaneous fat was also associated with delay in subsequent motor development (OR=2.27, 95% CI:1.08, 4.76). Conclusions Pediatric overweight and high subcutaneous fat are associated with delayed infant motor development. PMID:20227724

  10. About Armature Winding and Armature Circuit of DC Motor Circular Current Problem(Part 1)%关于直流电动机的电枢绕组及电枢电路(一)环流问题

    Institute of Scientific and Technical Information of China (English)

    王宗培; 陈敏祥

    2012-01-01

    The new DC motor (New DCM) shares the same armature winding with traditional DC motor (DCM) , all adopt seal connection (namely polygon connection) to combine K commutating units, the armature winding of New DCM is similar but are different with multi-phase AC motor's armature winding which employ typical polygon connection. New DCM is neither multi-phase AC motor nor multi-phase BLDCM. Multi-phase AC armature winding adopted typical polygon connection can have circular current in closed circuit. However, New DCM or DCM with seal connection armature winding will not and can not have circular current in closed circuit.%新直流电动机(New DCM)与传统有刷直流电动机(DCM)有相同的电枢绕组,都是分成K个换向单元成封闭形(多边形)接法,与多相交流电动机采取封闭形(多边形)接法的电枢绕组有类似之处但有区别,New DCM不是一台多相交流电动机,也不是一台多相无刷直流电动机.与典型多边形接法的多相交流电枢绕组闭合回路可能有环流的情况不同,New DCM或DCM为封闭形接法的电枢绕组,闭合回路内不存在环流,不可能产生环流.

  11. Motor variability--an important issue in occupational life.

    Science.gov (United States)

    Srinivasan, Divya; Mathiassen, Svend Erik

    2012-01-01

    Several recent reviews have reported that 'repetitive movements' is a risk factor for occupational musculoskeletal disorders (MSD) in the neck, shoulder and arm regions. More variation in biomechanical exposure is often suggested as an effective intervention in such settings. While increasing variation using extrinsic methods like job rotation may not always be possible in an industrial context, the intrinsic variability of the motor system may offer an alternative opportunity to increase variation. Motor variability (MV) refers to the natural variation in postures, movements and muscle activity observed to different extents in all tasks. The current review explores the state of the art in MV research from motor control, sports and occupational biomechanics literature to answer whether MV is important to consider in an occupational context, and if yes, whether this literature stimulates further studies to test if MV can be manipulated as a deliberate intervention for increasing biomechanical variation without jeopardizing production. PMID:22317100

  12. Accumulation and Decay Characteristics of Exoelectron Sources at MgO Protective Layer Surface in Alternating-Current Plasma Display Panels

    Science.gov (United States)

    Yoshino, Kyohei; Nagatomi, Takaharu; Morita, Yukihiro; Oue, Toshiyasu; Kosugi, Naoki; Nishitani, Mikihiko; Kitagawa, Masatoshi; Takai, Yoshizo

    2010-08-01

    The accumulation and decay characteristics of exoelectron sources at a MgO protective layer surface in alternating-current plasma display panels (AC-PDPs) were investigated. The positively charged MgO surface provides a larger number of exoelectrons than the negatively charged surface, indicating that electrons trapped in shallow carrier traps coexist with trapped holes, and exoelectrons are emitted through Auger and/or photoionization processes after their recombination. The exoelectron sources are accumulated by sustain discharges and always decay. The half-life of the decay of the exoelectron sources is relatively long, of the order of a few tens of ms, confirming that the exoelectron emission property at the address discharge in a certain television (TV) field is strongly affected by sustain firings in the previous two TV fields or more. The effects of such a long-term decay of the exoelectron sources should be taken into consideration when designing the driving waveforms of AC-PDPs.

  13. Motor homopolar

    OpenAIRE

    2007-01-01

    Mostramos la construcción de un modelo de motor homopolar, uno de los más antiguos tipos de motores eléctricos. Se caracterizan porque el campo magnético del imán mantiene siempre la misma polaridad (de ahí su nombre, del griego homos, igual), de modo que, cuando una corriente eléctrica atraviesa el campo magnético, aparece una fuerza que hace girar los elementos no fijados mecánicamente. En el sencillísimo motor homopolar colgado (Schlichting y Ucke 2004), el imán puede girar ...

  14. Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation

    Directory of Open Access Journals (Sweden)

    Leonardo Furlan

    2016-01-01

    Full Text Available Advances in our understanding of the neural plasticity that occurs after hemiparetic stroke have contributed to the formulation of theories of poststroke motor recovery. These theories, in turn, have underpinned contemporary motor rehabilitation strategies for treating motor deficits after stroke, such as upper limb hemiparesis. However, a relative drawback has been that, in general, these strategies are most compatible with the recovery profiles of relatively high-functioning stroke survivors and therefore do not easily translate into benefit to those individuals sustaining low-functioning upper limb hemiparesis, who otherwise have poorer residual function. For these individuals, alternative motor rehabilitation strategies are currently needed. In this paper, we will review upper limb immobilisation studies that have been conducted with healthy adult humans and animals. Then, we will discuss how the findings from these studies could inspire the creation of a neural plasticity model that is likely to be of particular relevance to the context of motor rehabilitation after stroke. For instance, as will be elaborated, such model could contribute to the development of alternative motor rehabilitation strategies for treating poststroke upper limb hemiparesis. The implications of the findings from those immobilisation studies for contemporary motor rehabilitation strategies will also be discussed and perspectives for future research in this arena will be provided as well.

  15. A novel induction motor starting method using superconduction

    Science.gov (United States)

    Silva, F. B. B.; Orlando, M. T. D.; Fardin, J. F.; Simonetti, D. S.; Baldan, C. A.

    2014-12-01

    In this paper, an alternative method for starting up induction motors is proposed, taking into account experimental measurements. The new starting current limitation method is based on using a high-temperature superconductor. A prototype of the superconducting starting current limiter was constructed with a commercially available second-generation high-temperature superconductor YBCO tape, and this was tested with a 55-kW industrial induction motor in a 440-V/60-Hz three-phase power grid. Performance evaluations of the superconducting limiter method (applied to startup of the induction motor) were performed and were compared with a direct-on-line starter and an electronic soft starter. In addition, a computational model was developed and used for electromagnetic torque analysis of the system. As significant characteristics, our method offers the ability to limit the starting current of the induction motor with greater electromagnetic torque, reduced current waveform distortion and therefore lower harmonic pollution during startup when compared to the soft starter method.

  16. Application of stepping motor

    International Nuclear Information System (INIS)

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  17. Study on the Current Status of Medical Alternative Animal Researches%医学动物替代研究发展现状研究

    Institute of Scientific and Technical Information of China (English)

    卫茂玲

    2016-01-01

    目的:了解我国动物替代研究发展现状,发现问题,提出对策。方法文献检索与定性描述法。以主题、篇名或关键词“动物替代”或“动物减少”或“动物优化”精确检索中文医学常用数据库中国知网、维普数据和万方数据库,补充查找相关研究参考文献。纳入分析组织建设、立法、医学教育和替代研究方法文献,并进行定性描述概括,检索时间截止2015年7月20日。结果初检引文219条,文献发表于1999-2014年,以描述性研究为主。动物替代研究领域包括皮肤刺激、眼刺激毒理学检测、热敏试验和动物模型替代等。替代研究信息交流平台已建立,部分教师已经在实践运用替代原则,相关专著已出版,但法规建设和验证体系滞后,替代研究认识还不乐观,验证方法研究不多。结论国内动物替代研究不多,缺乏系统化建设。未来应加强动物替代研究体系研究,重点在立法、政策引导、医学教育、人才培养和研究方法等。%Objective:To investigate the current status of alternative animal researches in China and thus find the problems and put forward countermeasures. Method: This study was carried out by the methods of literature search and qualitative description. The authors precisely searched the medicine databases commonly used in China ( CNKI, VIP, and Wanfang Data) using the MeSH word, title, or keyword namely"animal alternative","animal decrease" or"animal optimization", and added to find the related researches′references. Then the author included the literature regarding to the organization construction, legislation, medical education, and alternative research methods, and conducted a qualitative description. The deadline was July 20, 2015. Results:There were 219 ini-tial quotations published from 1999 to 2014, and mainly were descriptive researches. The fields of alternative ani-mal researches included skin

  18. 医学动物替代研究发展现状研究%Study on the Current Status of Medical Alternative Animal Researches

    Institute of Scientific and Technical Information of China (English)

    卫茂玲

    2016-01-01

    Objective:To investigate the current status of alternative animal researches in China and thus find the problems and put forward countermeasures. Method: This study was carried out by the methods of literature search and qualitative description. The authors precisely searched the medicine databases commonly used in China ( CNKI, VIP, and Wanfang Data) using the MeSH word, title, or keyword namely"animal alternative","animal decrease" or"animal optimization", and added to find the related researches′references. Then the author included the literature regarding to the organization construction, legislation, medical education, and alternative research methods, and conducted a qualitative description. The deadline was July 20, 2015. Results:There were 219 ini-tial quotations published from 1999 to 2014, and mainly were descriptive researches. The fields of alternative ani-mal researches included skin and eye stimulating toxicology test, thermal hyperalgesia and animal model replace-ment, and etc. The information communication platform of replacement researches had established, part of teachers were in practice using the substitution principle, the related monographs had been published, but the law and regu-lation construction and validation system were lag, the cognitive of replacement researches was not optimistic, and the validation method researches were insufficient. Conclusion: The domestic alternative animal researches were insufficient and lacking of systematic construction. It should strengthen the study on alternative animal research sys-tem, focused on legislation, policy leading, medical education, talent cultivation, and research methods.%目的:了解我国动物替代研究发展现状,发现问题,提出对策。方法文献检索与定性描述法。以主题、篇名或关键词“动物替代”或“动物减少”或“动物优化”精确检索中文医学常用数据库中国知网、维普数据和万方数据库,补充查找相关研

  19. Fault Detection based on MCSA for a 400Hz Asynchronous Motor for Airborne Applications

    Directory of Open Access Journals (Sweden)

    Steffen Haus

    2013-01-01

    Full Text Available Future health monitoring concepts in different fields of engineering require reliable fault detection to avoid unscheduled machine downtime. Diagnosis of electrical induction machines for industrial applications is widely discussed in literature. In aviation industry, this topic is still only rarely discussed.A common approach to health monitoring for electrical induction machines is to use Motor Current Signature Analysis (MCSA based on a Fast Fourier Transform (FFT. Research results on this topic are available for comparatively large motors, where the power supply is typically based on 50Hz alternating current, which is the general power supply frequency for industrial applications.In this paper, transferability to airborne applications, where the power supply is 400Hz, is assessed. Three phase asynchronous motors are used to analyse detectability of different motor faults. The possibility to transfer fault detection results from 50Hz to 400Hz induction machines is the main question answered in this research work. 400Hz power supply frequency requires adjusted motor design, causing increased motor speed compared to 50Hz supply frequency. The motor used for experiments in this work is a 800W motor with 200V phase to phase power supply, powering an avionic fan. The fault cases to be examined are a bearing fault, a rotor unbalance, a stator winding fault, a broken rotor bar and a static air gap eccentricity. These are the most common faults in electrical induction machines which can cause machine downtime. The focus of the research work is the feasibility of the application of MCSA for small scale, high speed motor design, using the Fourier spectra of the current signal.Detectability is given for all but the bearing fault, although rotor unbalance can only be detected in case of severe damage level. Results obtained in the experiments are interpreted with respect to the motor design. Physical interpretation are given in case the results differ

  20. 交流发光二极管热特性的模拟分析%Thermal Simulation of Alternating Current Light Emitting Diodes

    Institute of Scientific and Technical Information of China (English)

    邓辉; 陈忠; 吕毅军; 高玉琳; 朱丽虹; 陈莹亮; 林岳; 郭自泉; 王凯; 陈国龙

    2012-01-01

    由于交流发光二极管(AC-LED)在实际应用中无需交流/直流整流变压器,它的发展越来越被关注.随着器件功率的增大,芯片结温升高,对器件的光通量、光功率及寿命等产生负面影响,所以精确掌握AC-LED的温升规律就成为芯片设计的关键.运用FloEFD有限元软件进行模拟仿真1W白光AC-LED分别在直流和交变功率驱动下的瞬态热特性,结果表明在加载交变信号情况下,器件结温会以直流信号的结温为中心周期振荡,振荡的频率与输入功率频率相同,但有明显的相位移动.同时,AC-LED在不同的输入功率和频率下的结温变化显示稳态时的平均结温和结温振荡幅度都随功率的增大而线性上升,但随着频率的增大而降低.%Alternating current light emitting diodes (AC-LED) have attracted more and more attentions due to the advantage of free of alternate current (AC)/direct current (DC) converter in practical application. With the increase of input power, the rising junction temperature will have negative influence on the the luminous flux, the optical power, the lifetime and other parameters of LED. Therefore, the understanding of the principle of accurate temperature rise of AC-LED is the key to the chip design. The finite-element analysis software (FloEFD) is used to simulate the transient thermal properties of 1 W white AC-LED driven by DC and AC power respectively. The results show that the junction temperature of AC-LED driven by AC power, fluctuates periodically around that driven by DC power and the fluctuation frequency is the same as that of the input signal, but with an apparent phase shift. Meanwhile, the variation of junction temperature of AC-LED driven at different powers and frequencies shows that the average junction temperature and its fluctuation amplitude increases linearly with the input power at steady state, however, decreases with the increase of frequency.

  1. 直流控制系统对直流近区交流线路短路电流幅值的影响%Impacts of Direct Current Control System on Alternating Current Circuit Short-Circuit Current Amplitude near Direct Current Region

    Institute of Scientific and Technical Information of China (English)

    樊佳辉; 都洪基

    2016-01-01

    在故障期间良好的直流控制系统可以减少故障对电网的伤害。介绍了目前主流的直流控制系统逆变侧的结构及其主要参数,分析了控制系统的低压限流、最大触发角控制、电流放大器和换相失败预测等环节的基本结构,通过PSCAD/EMTDC软件搭建仿真模型,在故障期间分别限制不同控制环节的信号输出,研究其对短路电流幅值的影响,指出换相失败预测环节是影响直流近区交流线路短路电流幅值的直接因素,最大触发角控制和电流放大器环节间接影响短路电流幅值。%During malfunction a good direct current control system could reduce harm to grid from faults. Introduction was made to the structure of the main stream direct current control system at the side of inverter side and its major parameter at present. Analysis was made to the basic struc-ture of low-voltage current-limiting, maximum ifring angle control, current ampliifer and commutation defeating prediction etc links. The software PSCAD/EMTDC was used to construct the simulation model. During malfunction the signal outputs of different control links were limited. This paper studied its impact on the short-circuit current amplitude, and pointed out that the commutation defeating prediction link is the direct factor inlfuencing on the alternating current circuit short-circuit current amplitude near direct current region and the maximum ifring angle control and cur-rent ampliifer links indirectly affect on the short-circuit current amplitude.

  2. 基于单片机的电动机转速/电流控制系统设计%Design of Motor Speed/Current Control System Based on Singlechip

    Institute of Scientific and Technical Information of China (English)

    贾文哲; 王剑平; 康亚慧

    2016-01-01

    With the continuous development of modern society, there are increasing requirements for mechanical automation. For singlechip, there are higher requirements for the accuracy of the location and time. Therefore, how to improve the speed of the motor is an important subject of motor in modern society. This study takes 89C52 singlechip as the core, uses C language for programming control, produces adjustable square wave by the MCU internal timer, and designs the drive circuit based on the working principle and mathematic model of continuous current motor and Pulse width modulation (PWM) control principle and the basic principle of H bridge circuit. It adopts PWM technology to control the motor and achieves the goal of precise speed control through duty cycle calculation.%随着现代社会的不断发展,对机械自动化的要求也越来越高,对于单片机而言,对其位置和时间的精确度也提出了更高的要求,因此,如何提高电机的运动速度是现代社会电机的一个重要课题。本次研究以89C52单片机为核心,用C语言进行编程控制,采用单片机内部定时器产生可调的矩形波,依据直流电动机的工作原理和数学模型以及脉宽调制(PWM)控制原理和H桥电路基本原理设计了驱动电路,采用了PWM技术对电动机进行控制,通过对占空比的计算达到精确调速的目的。

  3. Alternative Solar Indices

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, L.J.

    1980-07-01

    Possible alternative Solar Indices which could either be a perturbation from the currently defined Solar Index or possible indices based on current technologies for other media markets are discussed. An overview is given of the current project, including the logic that was utilized in defining its current structure and then alternative indices and definitions are presented and finally, recommendations are made for adopting alternative indices.

  4. Overview of Current Loop Control Technology for Permanent Magnet Synchronous Motor Servo System%永磁同步电机伺服系统电流环控制技术综述

    Institute of Scientific and Technical Information of China (English)

    黄玉平; 郑再平; 仲悦; 吴红星

    2015-01-01

    The current loop is the most inner and important loop for permanent magnet synchronous motor servo system in the three control loops.The current loop control method and control technology has a direct impact on the dynamic performance of the whole system.Based on the analysis of permanent magnet synchro-nous motor mathematical model and vector control principle, the paper carried on the summary of the domes-tic and foreign research method and control strategy of current control of permanent magnet synchronous mo-tor control system in the three control loops.The operation characteristics of the novel current regulator and current decoupling method in the control system were analyzed.The current decoupling method on back elec-tromotive force compensation technology research and development were investigated and the current control technique was summarized.%电流环是永磁同步电机伺服系统三环控制最内,也是最重要的控制环节,电流环控制方法和控制技术的好坏直接影响整个系统的动态性能。本文在分析永磁同步电动机数学模型和矢量控制原理的基础上,针对永磁同步电机三环控制系统中的电流环控制国内外研究的方法和控制策略进行综述,分析新型电流调节器在控制系统中的作用及工作特点,探讨现有的电流解耦方法对反电势补偿技术研究发展动态,并对电流控制技术进行总结。

  5. Comparison of Removal Effects in Azo Dyed Wastewater between Direct Current and Alternating Current Electrocoagulation%直流电和交流电凝聚法处理偶氮染料废水的对比研究

    Institute of Scientific and Technical Information of China (English)

    赵玉华; 苍晓艺; 赵首权; 金德才; 董瑞蛟

    2011-01-01

    The paper aimed to compare the different effects of removing azo dye in wastewater between direct current(DC) and alternating current(AC) electrocoagulation methods, and explored the impact of current density on the treatment effect. In this experiment, iron was served as anode, graphite column was served as cathode, the current density was changed, contrastive experiments were carried out with DC and AC electrocoagulation methods. The results showed that the removal ratio of azo dye concentration increased with the increase of the current density, when the current density was 0. 083 mA/cm2, the removal ratio of azo dye concentration arrived at 97.63%, which also removed colority, CODcr, NH3-N to a certain degree. But the treatment ability of azo dye in wastewater by AC electrocoagulation was poor, and the maximum removal ratio of azo dye concentration was only 16. 01%. Thus, DC electrocoagulation combined with electrolysis,flocculation,and other functions could treat azo dyed wastewater effectively. However, removal of azo dye from wastewater by AC electrocoagulation could not get significant effect.%目的 考查直流电凝聚法和交流电凝聚法对偶氮染料废水处理效果的差异.探索电流密度对处理效果的影响.方法 以铁皮为阳极,石墨柱为阴极,改变电流密度,分别用直流电和交流电进行电凝聚对比试验.结果 直流电凝聚法对染料质量浓度的去除率随电流密度的增大而增大,当电流密度为0.083 mA/cm2时,染料质量浓度的去除率达到97.63%.同时,色度、CODCr、氨氮也有一定的去除效果.而交流电凝聚法对偶氮染料废水的处理能力较差,其染料质量浓度的最大去除率为16.01%.结论 直流电凝聚法在电解、絮凝等共同作用下可有效的处理偶氮染料废水,而交流电凝聚法对偶氮染料废水的处理无明显效果.

  6. Coupling dynamic equations of motor-driven elastic linkage mechanism with links fabricated from three-dimensional braided composite materials

    Institute of Scientific and Technical Information of China (English)

    CAI Gan-wei; WANG Xiang; WANG Ru-gui; LI Zhao-jun; ZHANG Xiao-bin; CANG Ping-ping

    2005-01-01

    A motor-driven linkage system with links fabricated from 3-dimensional braided composite materials was studied. A group of coupling dynamic equations of the system, including composite materials parameters, electromagnetism parameters of the motor and structural parameters of the link mechanism, were established by finite element method. Based on the air-gap field of non-uniform airspace of three-phase alternating current motor caused by the vibration eccentricity of rotor, the relation of electromechanical coupling at the actual running state was analyzed. And the motor element, which defines the transverse vibration and torsional vibration of the motor as its nodal displacement, was established. Then, based on the damping element model and the expression of energy dissipation of the 3-dimentional braided composite materials, the damping matrix of the system was established by calculating each order modal damping of the mechanism.

  7. Peculiar Features of Burning Alternative Motor Fuels

    Directory of Open Access Journals (Sweden)

    M. Assad

    2006-01-01

    Full Text Available Some peculiar features of air-hydrogen mixture combustion process in a modeling combustion chamber are given in the paper. Dependences of burning duration of various fuel types on initial pressure have been obtained. The paper considers dynamics of changes in pressure and ignition rate of some fuel types in the combustion chamber.

  8. Flood-proof motors

    International Nuclear Information System (INIS)

    Even before the Fukushima event occurred some German nuclear power plants (NPP) have considered flooding scenarios. As a result of one of these studies, AREVA performed an upgrade project in NPP Isar 1 with flood-proof motors as a replacement of existing air-cooled low-voltage and high-voltage motors of the emergency cooling chain. After the Fukushima event, in which the cooling chains failed, the topic flood-proof equipment gets more and more into focus. This compact will introduce different kinds of flood-proof electrical motors which are currently installed or planned for installation into NPPs over the world. Moreover the process of qualification, as it was performed during the project in NPP Isar 1, will be shown. (orig.)

  9. Chaos control of the brushless direct current motor using adaptive dynamic surface control based on neural network with the minimum weights

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Shaohua [School of Automation, Chongqing University, Chongqing 400044 (China); Department of Mechanical Engineering, Chongqing Aerospace Polytechnic, Chongqing, 400021 (China); Wu, Songli [Department of Mechanical Engineering, Chongqing Aerospace Polytechnic, Chongqing, 400021 (China); Gao, Ruizhen [School of Automation, Chongqing University, Chongqing 400044 (China)

    2015-07-15

    This paper investigates chaos control for the brushless DC motor (BLDCM) system by adaptive dynamic surface approach based on neural network with the minimum weights. The BLDCM system contains parameter perturbation, chaotic behavior, and uncertainty. With the help of radial basis function (RBF) neural network to approximate the unknown nonlinear functions, the adaptive law is established to overcome uncertainty of the control gain. By introducing the RBF neural network and adaptive technology into the dynamic surface control design, a robust chaos control scheme is developed. It is proved that the proposed control approach can guarantee that all signals in the closed-loop system are globally uniformly bounded, and the tracking error converges to a small neighborhood of the origin. Simulation results are provided to show that the proposed approach works well in suppressing chaos and parameter perturbation.

  10. Validating the Rett Syndrome Gross Motor Scale

    OpenAIRE

    Jenny Downs; Michelle Stahlhut; Kingsley Wong; Birgit Syhler; Anne-Marie Bisgaard; Peter Jacoby; Helen Leonard

    2016-01-01

    Rett syndrome is a pervasive neurodevelopmental disorder associated with a pathogenic mutation on the MECP2 gene. Impaired movement is a fundamental component and the Rett Syndrome Gross Motor Scale was developed to measure gross motor abilities in this population. The current study investigated the validity and reliability of the Rett Syndrome Gross Motor Scale. Video data showing gross motor abilities supplemented with parent report data was collected for 255 girls and women registered with...

  11. Control of a Dual-Stator Flux-Modulated Motor for Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Xinhua Guo

    2016-07-01

    Full Text Available This paper presents the control strategies for a novel dual-stator flux-modulated (DSFM motor for application in electric vehicles (EVs. The DSFM motor can be applied to EVs because of its simple winding structure, high reliability, and its use of two stators and rotating modulation steels in the air gap. Moreover, it outperforms conventional brushless doubly-fed machines in terms of control performance. Two stator-current-oriented vector controls with different excitation in the primary winding, direct and alternating current excitation, are designed, simulated, and evaluated on a custom-made DSFM prototype allowing the decoupled control of torque. The stable speed response and available current characteristics strongly validate the feasibility of the two control methods. Furthermore, the proposed control methods can be employed in other applications of flux-modulated motors.

  12. Analysis of water flow, power and electrical current of a motor pump powered by photovoltaic panels; Analise da vazao, potencia e corrente em uma motobomba acionada por paines fotovoltaicos

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Paulo Takashi; Santos, Jose Airton Azevedo dos; Michels, Roger Nabeyama [Universidade Tecnologica Federal do Parana (UTFPR-MD), Medianeira, PR (Brazil)], E-mail: airton@utfpr.edu.br; Ricieri, Reinaldo Prandini [Universidade do Oeste Paulista (UNIOESTE), Cascavel, PR (Brazil). Dept. de Engenharia Agricola], E-mail: ricieri@unioeste.br; Halmeman, Maria Cristina Rodrigues [Universidade Tecnologica Federal do Parana (UTFPR-CM), Campo Mourao, PR (Brazil)

    2009-07-01

    Because of the high cost of electricity connection to distant places, far away from conventional nets, photovoltaic solar energy is widely used in public illumination, water pumping, medical care centers, etc. With the purpose to contribute to a better utilization in this type of energy, the object of the project is to analyze the water flow, power and electrical current of a motor pump to be used for water lift, driven by photovoltaic panels, the data will be collected at every 2 meters in height from 2.2 to 18.2 meters. The analyses show the outflow linear dependence in relation to the height of the water lift, a second order dependence of the electrical power provided by the photovoltaic panels in relation to the solar irradiance on the panels and a linear dependence of the electrical current in relation to the solar irradiance. This study is a part of a project developed at the 'Universidade Tecnologica Federal do Parana' (UTFPR) - Campus Medianeira - PR. Two photovoltaic panels were used from Solarex Brand, model MSX 56, a motor pump made by Shurflo Ltd, model 2088-732, two pyranometers from KIPP and ZONEN CM3, a type K thermocouple, a pressure transducer model HUBA-510 and a water flow transducer. (author)

  13. 振荡磁场量子点中自旋流的交流响应%Alternating response of spin current in a magnetic-oscillating quantum dot

    Institute of Scientific and Technical Information of China (English)

    宋红岩; 宋小龙; 张爱芳; 吴留坡; 施耀铭

    2007-01-01

    We investigate alternating response of the spin current in a quantum dot system coupled to a normal metal electrode, to which an alternating driving voltage and a pumping rotating magnetic field are applied. The expression of the time-averaged spin current and its differential is obtained based on a non-equilibrium Green's function method. We find that for a given rotating frequency, the spin current increases rapidly and appears to have small steps when the driven frequency increases. As the driven frequency is further increasing, the spin current can be significantly enhanced and approaches a stable value. The photon-assisted processes bring about interesting features of spin current. The influence of the gate voltage and temperature on the spin current is examined in detail.

  14. Alternative current conduction mechanisms of organic-inorganic compound [N(CH3)3H]2CuCl4

    Science.gov (United States)

    Ben Bechir, M.; Karoui, K.; Tabellout, M.; Guidara, K.; Ben Rhaiem, A.

    2014-05-01

    The [N(CH3)3H]2CuCl4 single crystal has been analyzed by X-ray powder diffraction patterns, differential scanning calorimetry (DSC), and electrical impedance spectroscopy. [N(CH3)3H]2CuCl4 crystallizes at room temperature in the monoclinic system with P21/C space group. Three phase transitions at T1 = 226 K, T2 = 264 K, and T3 = 297 K have been evidenced by DSC measurements. The electrical technique was measured in the 10-1-107 Hz frequency range and 203-313 K temperature intervals. The frequency dependence of alternative current (AC) conductivity is interpreted in terms of Jonscher's law (developed). The AC electrical conduction in [N(CH3)3H]2CuCl4 compound is studied by two processes which can be attributed to a hopping transport mechanism: the correlated barrier hopping model in phases I, II, and III, the non-overlapping small polaron tunneling model in phase IV. The conduction mechanism is interpreted with the help of Elliot's theory, and the Elliot's parameters are found.

  15. Enhancing the versatility of alternate current biosusceptometry (ACB) through the synthesis of a dextrose-modified tracer and a magnetic muco-adhesive cellulose gel

    Energy Technology Data Exchange (ETDEWEB)

    Martins, Murillo L., E-mail: murillolongo@gmail.com [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark); Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Calabresi, Marcos F.; Quini, Caio; Matos, Juliana F.; Miranda, José R.A.; Saeki, Margarida J. [Instituto de Biociências, Universidade Estadual Paulista, CP 510, 18618–970 Botucatu SP (Brazil); Bordallo, Heloisa N. [Niels Bohr Institute, University of Copenhagen, DK-2100 Copenhagen (Denmark)

    2015-03-01

    Alternate Current Biosusceptometry (ACB) is a promising bio-magnetic method, radiation free and easily performed used for gastric emptying exams. Due to development on its sensitivity level, interesting nature, noninvasiveness and low cost it has attracted a lot of attention. In this work, magnetic nanoparticles of Mn–Zn ferrite as well as dextrose-modified nanoparticles were synthesized to be used as possible tracers in ACB gastric emptying exams. In addition, a magnetic muco-adhesive gel was obtained by modifying the ferrite nanoparticles with cellulose. Based on in-vivo tests in rats, we show that the pure ferrite nanoparticles, whose isoelectric point was found to be at pH = 3.2, present a great sensitivity to pH variations along the gastrointestinal tract, while the reduction of the isoelectric point by the dextrose modification leads to suitable nanoparticles for rapid gastric emptying examinations. On the other hand, the in-vivo tests show that the muco-adhesive cellulose gel presents substantial stomach adhesion and is a potential drug delivery system easily traceable by the ACB system.

  16. Treating waste waters in small agglomerations. The current situation, commitments and alternatives; Depuracion de las aguas residuales en pequenos nuclear. Situacion actual, compromisos y alternativas

    Energy Technology Data Exchange (ETDEWEB)

    Collado Lara, R. [Universidad de Cantabria. (Spain)

    2003-07-01

    In 1991, the European Economic Community issued a directive on urban waste water treatment: (91/27/EEC). This directive laid down that such treatment had to be in place ny the period 2000-2005, depending on the application of different requirements according to the size of the agglomeration and the discharge area. A large number of sewage plants are being built in Spain at the present time, especially in medium-size and large agglomeration (pop>10.000 inhabitants). However, in the smaller agglomeration, over 50% of the waste waters have still to be treated. In agglomerations of less than 10.000 inhabitants, which make up 95% of the municipalities in Spain, it is possible to apply a greater diversity of treatments not all of them conventional that comply with the directive in question. Natural systems and biofilm processes are low-cost solutions that are well adapted to the natural environment. However, conventional technologies are virtually essential in medium-size and large agglomerations, as the lack of space and the exacting demands render them irreplaceable (Collado, 2002). This article describes the distribution of the municipalities in Spain according to the number of inhabitants, the current state os sewage treatment,the commitments made by the European Economic Community and the viable alternatives. Some comments have been added regarding the running of such systems and the need for them to be managed by associations of local councils or regional bodies. (Author)

  17. Novel method for rapid in-situ hybridization of HER2 using non-contact alternating-current electric-field mixing

    Science.gov (United States)

    Saito, Yoshitaro; Imai, Kazuhiro; Nakamura, Ryuta; Nanjo, Hiroshi; Terata, Kaori; Konno, Hayato; Akagami, Yoichi; Minamiya, Yoshihiro

    2016-01-01

    Human epidermal growth factor receptor 2 (HER2)-targeted agents are an effective approach to treating HER2-positive breast cancer patients. However, the lack of survival benefit in HER2-negative patients as well as the toxic effects and high cost of the drugs highlight the need for accurate and prompt assessment of HER2 status. Our aim was to evaluate the clinical utility of a novel rapid dual in-situ hybridization (RISH) method developed to facilitate hybridization. The method takes advantage of the non-contact mixing effect of an alternating current (AC) electric field. One hundred sixty-three specimens were used from patients diagnosed with primary breast cancers identified immunohistochemically as HER2 0/1(+), (2+) or (3+). The specimens were all tested using conventional dual in-situ hybridization (DISH), DISH with an automated slide stainer, and RISH. With RISH the HER2 test was completed within 6 h, as compared to 20–22 h needed for the standard protocol. Although RISH produced results more promptly using smaller amounts of labeled antibody, the staining and accuracy of HER2 status evaluation with RISH was equal to or greater than with DISH. These results suggest RISH could be used as a clinical tool to promptly determine HER2 status. PMID:27443187

  18. Preliminary evaluation of wheelchair occupant restraint system usage in motor vehicles.

    Science.gov (United States)

    van Roosmalen, Linda; Bertocci, Gina E; Hobson, Douglas A; Karg, Patricia

    2002-01-01

    Individuals using wheeled mobility devices (WMDs) often use them as motor vehicle seats during transportation. Wheelchair occupant restraint systems (WORSs), consisting of upper torso and pelvic restraints, are usually mounted to the structure of transit vehicles to secure individuals within their wheelchair seats. This preliminary study attempts to evaluate the use and satisfaction of currently installed vehicle-mounted WORSs for individuals using WMD as seats in motor vehicles. A survey was conducted among 33 adults who use their WMD to travel in motor vehicles. Results from the survey showed that upper torso and pelvic restraints installed in private vehicles are quick, comfortable, and easy to use. However, WORS installed in mass transit and paratransit are often uncomfortable to wear, difficult to reach, and time-consuming to use. This preliminary study documents the growing need for developing alternative WORS that are safe, comfortable, and that allow independent usage for wheelchair occupants while traveling in a motor vehicle.

  19. Analysis of Rotor Eddy-current Loss in High-speed Permanent Magnet Motors%高速永磁电机的转子涡流损耗分析

    Institute of Scientific and Technical Information of China (English)

    高鹏飞; 房建成; 韩邦成; 孙津济

    2013-01-01

    For high-speed permanent magnet motors,the rotor eddy-current loss cannot be underestimated in that it has serious implications on the motors' efficiency or even demagnetizes the permanent magnets because of the overheating problem.The sources of the harmonics which produce the rotor eddy-current loss were put forward,and the analytical calculation was presented,then the loss of different motor structures were analyzed,and the influences of various stator slot numbers,slot opening width,airgap length,the shield and the auxiliary slot were studied.The results show that the rotor eddy-current loss can be reduced by more slots,thinner slot opening width and larger airgap length.It also comes to the conclusion that a shield with high conductivity between the retaining sleeve and permanent magnets can reduce the rotor eddy-current loss,and a proper thickness of the shied can help to minimize the loss.The auxiliary slot is studied,and with proper width,depth angle and type,the auxiliary slot can be used to reduce the rotor eddy-current loss and cool the motors.The research is of great value in theory and engineer applications for high-speed permanent magnet motors.%在高速永磁电机中,转子涡流损耗会使转子温度升高,影响电机效率等性能,甚至导致永磁体过热退磁.针对高速永磁电机中的转子涡流损耗问题,进行了解析分析和有限元计算,分析了产生转子涡流损耗的谐波来源,研究了不同定转子结构电机的转子涡流损耗,分析了定子槽数、槽口宽度、气隙长度、屏蔽层、定子齿开辅助槽对转子涡流损耗的影响.结果表明,增加定子槽数、减小槽口宽度、增加气隙长度可以减小转子涡流损耗;在护套和永磁体中间加一层高电导率屏蔽层能有效减小永磁体的涡流,且选择合适的屏蔽层厚度能够进一步减小转子涡流损耗;提出了使用合适宽度、深度、角度和槽型的辅助槽来减小转子涡流损耗、

  20. Understanding social motor coordination.

    Science.gov (United States)

    Schmidt, R C; Fitzpatrick, Paula; Caron, Robert; Mergeche, Joanna

    2011-10-01

    Recently there has been much interest in social coordination of motor movements, or as it is referred to by some researchers, joint action. This paper reviews the cognitive perspective's common coding/mirror neuron theory of joint action, describes some of its limitations and then presents the behavioral dynamics perspective as an alternative way of understanding social motor coordination. In particular, behavioral dynamics' ability to explain the temporal coordination of interacting individuals is detailed. Two experiments are then described that demonstrate how dynamical processes of synchronization are apparent in the coordination underlying everyday joint actions such as martial art exercises, hand-clapping games, and conversations. The import of this evidence is that emergent dynamic patterns such as synchronization are the behavioral order that any neural substrate supporting joint action (e.g., mirror systems) would have to sustain.

  1. THE MOTOR

    DEFF Research Database (Denmark)

    Gammelgaard Nielsen, Anders

    2011-01-01

    MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...

  2. Motor Magnates

    Institute of Scientific and Technical Information of China (English)

    ISABEL DING

    2008-01-01

    @@ The automotive industry is often seen as a man's world. Wang Fengying (王风英) begs to differ. The 38-year-old has presided over Great Wall Motors (长城汽车), the leading pick-up truck and Sport Utility Vehicle(SUV) manufacturer in China for the past five years.

  3. Motor radiculopathy

    OpenAIRE

    Khan, Afsha; Camilleri, Jeremy

    2012-01-01

    A 48-year-old immunosuppressed woman presented to a rheumatology follow-up clinic after suffering from herpes zoster infection. She had manifestations of foot drop 3 months after the initial infection. She was diagnosed with motor radiculopathy following herpes zoster infection that was effectively managed by physiotherapy and amitriptyline.

  4. Motor cortical plasticity induced by motor learning through mental practice.

    Directory of Open Access Journals (Sweden)

    Laura eAvanzino

    2015-04-01

    Full Text Available Several investigations suggest that actual and mental actions trigger similar neural substrates. Motor learning via physical practice results in long-term potentiation (LTP-like plasticity processes, namely potentiation of M1 and a temporary occlusion of additional LTP-like plasticity. However, whether this neuroplasticity process contributes to improve motor performance through mental practice remains to be determined. Here, we tested skill learning-dependent changes in primary motor cortex (M1 excitability and plasticity by means of transcranial magnetic stimulation in subjects trained to physically execute or mentally perform a sequence of finger opposition movements. Before and after physical practice and motor-imagery practice, M1 excitability was evaluated by measuring the input-output (IO curve of motor evoked potentials. M1 long-term potentiation (LTP and long-term depression (LTD-like plasticity was assessed with paired-associative stimulation (PAS of the median nerve and motor cortex using an interstimulus interval of 25 ms (PAS25 or 10 ms (PAS10, respectively. We found that even if after both practice sessions subjects significantly improved their movement speed, M1 excitability and plasticity were differentially influenced by the two practice sessions. First, we observed an increase in the slope of IO curve after physical but not after motor-imagery practice. Second, there was a reversal of the PAS25 effect from LTP-like plasticity to LTD-like plasticity following physical and motor-imagery practice. Third, LTD-like plasticity (PAS10 protocol increased after physical practice, whilst it was occluded after motor-imagery practice. In conclusion, we demonstrated that motor-imagery practice lead to the development of neuroplasticity, as it affected the PAS25- and PAS10- induced plasticity in M1. These results, expanding the current knowledge on how motor-imagery training shapes M1 plasticity, might have a potential impact in

  5. Why were alternating-current-driven electrochemiluminescence properties from Ru(bpy)3(2+) dramatically improved by the addition of titanium dioxide nanoparticles?

    Science.gov (United States)

    Tsuneyasu, Shota; Ichihara, Kazuki; Nakamura, Kazuki; Kobayashi, Norihisa

    2016-06-28

    Electrochemiluminescence (ECL) is a phenomenon in which light is emitted from the excited state of a redox-active material generated by electrochemical reactions. Among light-emitting devices, ECL devices have various advantages in terms of structure and ease of fabrication, and therefore, they are expected to be next-generation emitting devices. In this study, we introduced rutile-type titanium dioxide nanoparticles (TiO2 NPs) in a Ru(ii)-complex-based electrolyte to improve the emission properties of an alternating current (AC)-driven ECL device. The properties of the ECL device with TiO2 NPs were greatly improved (emission luminescence, 165 cd m(-2); half-life time, 1000 s) compared to a previously reported AC-driven ECL device without nanoparticles. To determine how TiO2 NPs helped in achieving high emission luminescence and long-term stability, we measured the optical and electrochemical properties of the Ru(bpy)3(2+)-based ECL solution in detail. The PL intensity of Ru(bpy)3(2+) was increased by adding TiO2 NPs, which indicated that the suppression of non-radiative quenching of the complex's excited states could improve the ECL intensity. With respect to the enhanced stability, electron transfers between Ru(bpy)3(2+) and TiO2 were suggested by detailed electrochemical measurements. These electron transfers occurred from the reduced Ru(bpy)3(2+) species to the TiO2, and subsequently, from the TiO2 to the oxidized Ru(bpy)3(2+) species. Such electron transfers are thought to improve the balance of the redox reactions in the ECL device, leading to long-term stability. PMID:27253475

  6. Analysis of Vibration and Acoustic Noise in Permanent Magnet Motors.

    Science.gov (United States)

    Hwang, Sangmoon

    . The effect of various design parameters on the output torque and torque ripple are discussed. Design parameters include winding patterns, magnetization direction, magnet arc length, number of segments in poles and magnet pole shaping. New designs of trapezoidal BEMF motors are proposed to reduce the electromagnetic torque ripple. Magnet stepping and magnet edge shaping with reduced arc length, significantly reduce torque ripple, with minimal sacrifice of the maximum output torque. Acoustic noise of electromagnetic origin is investigated using a magnetic frame which emulates a DC motor. The driving electromagnetic force is calculated using finite element analysis and the resulting vibration and acoustic noise is measured. Acoustic noise of purely electromagnetic origin was also tested with a DC brushless motor to confirm the results of the magnetic frame. The mechanism of noise generation in a DC motor is a quasi-static response of a stator not only at the fundamental frequency but also at higher harmonic frequencies of alternating switched DC, which is a current characteristic of a DC motor. Noise generation is significantly aggravated when some of those harmonics are close to the resonant frequencies of the stator. Therefore, acoustic noise is highly dependent upon the excitation current shape, as higher harmonics may match with resonant frequencies of the stator.

  7. System and method for determining stator winding resistance in an AC motor using motor drives

    Science.gov (United States)

    Lu, Bin; Habetler, Thomas G; Zhang, Pinjia

    2013-02-26

    A system and method for determining the stator winding resistance of AC motors is provided. The system includes an AC motor drive having an input connectable to an AC source and an output connectable to an input terminal of an AC motor, a pulse width modulation (PWM) converter having switches therein to control current flow and terminal voltages in the AC motor, and a control system connected to the PWM converter. The control system generates a command signal to cause the PWM converter to control an output of the AC motor drive corresponding to an input to the AC motor, selectively generates a modified command signal to cause the PWM converter to inject a DC signal into the output of the AC motor drive, and determines a stator winding resistance of the AC motor based on the DC signal of at least one of the voltage and current.

  8. IC Design of Motor Ignitor

    Institute of Scientific and Technical Information of China (English)

    TANG Zheng-wei; ZHOU Zhong-qiang

    2008-01-01

    On the basis of analysing traditional motor ignitor, a new motor ignitor design with precise ignition angle control, consistency and low cost is proposed. Techniques of low pertinence to process and power supply are introduced to promote its stability, reliability and unity. This circuit is implemented with a standard CMOS technology with perfect electric static discharge(ESD) design and can work under a broad range of power supply from 3V~5V with a quiescent current less than 2mA and can be widely used in motor with a displacement of 125ml and below.

  9. Energy Efficiency Standards of Induction Motors, ¿Are you Prepared Latin America?

    Directory of Open Access Journals (Sweden)

    Carlos M. Londoño-Parra

    2013-06-01

    Full Text Available In Colombia the regulatory process regarding the energy efficiency of end-use prod-ucts is emerging with the draft technical regulation product labeling RETIQ, which includes in Annex E, the test methods for determining the efficiency of motors alternat-ing current induction. The goal of this paper is to compare the energy efficiency of induction motors between the countries of Latin America and the countries of the major economies of the globe, considering four aspects: the current state of classification standards and test procedures of induction motors efficiency, multilateral agreements of mutual recognition, the infrastructure to conduct tests of the standard and support programs to improve the efficiency of electric motor-driven systems. The study reveals that Latin America is a considerable delay in the implementation of classification standards and methods for testing the efficiency of electric motors, most widely used in the world: IEC 60034-30:2008, IEC 60034-2-1: 2007 IEEE 112:2004 and EPAct'92, with respect to the countries of the European Union, United States, China, Australia, and other developed countries, in which these standards have been adopted. Furthermore, the region is evident in the absence of programs focused on improving the energy efficiency of electric motors and a limited number of accredited laboratories to evaluate their efficiency, which leads to most Latin American countries to establish agreements mutual recognition for this purpose.

  10. Energy Efficiency Standards of Induction Motors, ¿Are you Prepared Latin America?

    Directory of Open Access Journals (Sweden)

    Carlos M. Londoño-Parra

    2013-06-01

    Full Text Available In Colombia the regulatory process regarding the energy efficiency of end-use products is emerging with the draft technical regulation product labeling RETIQ, which includes in Annex E, the test methods for determining the efficiency of motors alternating current induction. The goal of this paper is to compare the energy efficiency of induction motors between the countries of Latin America and the countries of the major economies of the globe, considering four aspects: the current state of classification standards and test procedures of induction motors efficiency, multilateral agreements of mutual recognition, the infrastructure to conduct tests of the standard and support programs to improve the efficiency of electric motor-driven systems. The study reveals that Latin America is a considerable delay in the implementation of classification standards and methods for testing the efficiency of electric motors, most widely used in the world: IEC 60034-30:2008, IEC 60034-2-1: 2007 IEEE 112:2004 and EPAct'92, with respect to the countries of the European Union, United States, China, Australia, and other developed countries, in which these standards have been adopted. Furthermore, the region is evident in the absence of programs focused on improving the energy efficiency of electric motors and a limited number of accredited laboratories to evaluate their efficiency, which leads to most Latin American countries to establish agreements mutual recognition for this purpose.

  11. Neuronal control of turtle hindlimb motor rhythms.

    Science.gov (United States)

    Stein, P S G

    2005-03-01

    The turtle, Trachemys scripta elegans, uses its hindlimb during the rhythmic motor behaviors of walking, swimming, and scratching. For some tasks, one or more motor strategies or forms may be produced, e.g., forward swimming or backpaddling. This review discusses experiments that reveal characteristics of the spinal neuronal networks producing these motor behaviors. Limb-movement studies show shared properties such as rhythmic alternation between hip flexion and hip extension, as well as variable properties such as the timing of knee extension in the cycle of hip movements. Motor-pattern studies show shared properties such as rhythmic alternation between hip flexor and hip extensor motor activities, as well as variable properties such as modifiable timing of knee extensor motor activity in the cycle of hip motor activity. Motor patterns also display variations such as the hip-extensor deletion of rostral scratching. Neuronal-network studies reveal mechanisms responsible for movement and motor-pattern properties. Some interneurons in the spinal cord have shared activities, e.g., each unit is active during more than one behavior, and have distinct characteristics, e.g., each unit is most excited during a specific behavior. Interneuronal recordings during variations support the concept of modular organization of central pattern generators in the spinal cord.

  12. High Performance Speed Sensorless Control of Three-Phase Induction Motor Based on Cloud Computing

    Directory of Open Access Journals (Sweden)

    Z. M. Salem

    2012-10-01

    Full Text Available Induction motor is a cast of alternating current motor where charge endures allotted to the rotor close-at-hand deputation of conductive charge. These motors are broadly applied in industrial claim due to they are arduous along with adhere no contacts. The speed controller of deltoid phase induction motor is applied to alleviate the aberration of speed. The central constructivist of this paper is to accrue the performance of speed sensorless control of three phase induction motor. To increase its performance, this paper presents a modified method for speed controller of an indirect vector-controlled induction motor drive using cloud computing technique. Our methodology depends on speed sensorless scheme to obtain the speed signal feedback; the speed estimator is based on model reference adaptive control that uses the stator current and rotor flux as state variables for estimating the speed. In this method, the stator current error is represented as a function of first degree of the estimated speed error. An analysis and simulation of the tried algorithm is birthed and applied easing a TMS320C31 floating-point notational alert Processor. And accumulate the action of the three phase induction motor we conceived our appraisals affixed to the accountant based on cloud computing tactics. This intelligent policy uses the guidelines of the speed controller efficiently. Simulation and experimental results depicted that the motor speed is decelerated articulately to destine its illusion apprise without above and inferior smack and with about zero steady state error. The apprised accelerate alert and its dispatching buoy amassed off line from burlesque. After effects display an advantageous affinity among the accounted speed alert and it's dispatching allocated as well as aped speed flares

  13. Algorithm of Alternating Current Schedule Power Flow for Bulk Interconnected Grid%大型互联电网交流计划潮流算法

    Institute of Scientific and Technical Information of China (English)

    丁平; 李亚楼; 田芳; 李柏青; 严剑峰; 于之虹; 周孝信; 罗志强

    2014-01-01

    In China Power Grid, calculation of alternating current schedule power flow is an important foundation for checking security of schedule. An algorithm of AC schedule power flow applied to bulk interconnected power system was put forward in this paper. The principle of calculating was set firstly, which include four points, namely faithfulness, diversity by area, reality, selectable. Then solution based on interfaces controlling method was given. An approach to active schedule step by step was offered with three means of distributing unbalance power. To regulate reactive power, a method taking advantage of react power arranged in similar power flow was employed, which included using voltage of similar power flow as initial and determining parameter variation referring to closeness between active power of schedule and similar power flow. The algorithm was validated by cases from IEEE 39-node and China State Grid. The algorithm proposed is convergent well, can give power flow close to schedule data and situation appearing in power system, and owns good value for popularization and application.%在中国电网,交流计划潮流计算是校核计划安全性的重要基础。该文提出适用于大型互联电网的交流计划潮流算法。首先确立计算必须遵循的忠实性、分区域、真实性和可选择等4个原则;然后给出基于多断面控制法的实现方案。提出分阶段逐步逼近有功计划的方法,并给出3种不同的不平衡功率分配方式;提出以相似潮流中无功分布为初值并根据有功潮流相似度决定参数变化范围的无功调整方法。所提算法的有效性用 IEEE 39节点和中国国家电网的算例进行了验证。所提算法收敛性强,能给出与计划值和电网实际情况高度接近的潮流结果,具有良好的推广应用价值。

  14. The behavior of dissolution/passivation and the transformation of passive films during electrocoagulation: Influences of initial pH, Cr(VI) concentration, and alternating pulsed current

    International Nuclear Information System (INIS)

    Highlights: • Initial pH, Cr(VI) and APC could affect the behavior of dissolution/passivation in Fe-EC. • A dissolution/passivation region was constructed with different initial pH-Cr(VI). • The film was rich in Fe and Cr at high Cr(VI), whereas with lots of Fe but negligible of Cr at low Cr(VI). • The film was non-protective at long TAPC, but became more stable and protective at short TAPC. • Behavior of dissolution/passivation and passive film transformation in Fe-EC was elucidated. - Abstract: The passivation behavior of an iron anode for electrocoagulation (EC) was first investigated using response surface methodology (RSM). Tested initial pH range, Cr(VI) concentration and alternating pulsed current (APC) were 4.0 to 8.0, 52 to 520 mg L−1 and 10 to 590 s, respectively. The distance between electrodes was 25 mm, and K2SO4 (1 g L−1) was used as the supporting electrolyte in a 2.5 L EC reactor. Results confirmed that initial pH, Cr(VI) concentration, and APC significantly influence the extent of passivation. Then, based on the interaction effect on passivation behavior between initial pH and Cr(VI) in RSM, a pH-Cr(VI)-dissolution/passivation diagram was constructed with galvanostatic measurements. The diagram showed an optimal dissolution region for EC operation. This optimum was characterized by a reasonable final pH for extended precipitation and little passivation. Results of the cyclic voltammetry and X-ray photoelectron spectroscopy revealed a significant difference in the composition and stability of oxide films in the region with more pronounced passivation. Interestingly, the APC had both positive and negative effect on the passivation behavior. Long period of APC (TAPC = 590 s) produced a non-protective film, which favored the Fe0 dissolution. However, a more stable and protective passive film with a uniform structure of Fe and Cr oxides was formed by short TAPC (10 s). Based on the above results, this study elucidated the behavior of

  15. Electrical engineering of engineers 2. Alternative current engineering, loci diagrams, transformers, multiphase systems. A lecture and working book for the basic study. 8 ed.; Elektrotechnik fuer Ingenieure 2. Wechselstromtechnik, Ortskurven, Transformator, Mehrphasensysteme. Ein Lehr- und Arbeitsbuch fuer das Grundstudium

    Energy Technology Data Exchange (ETDEWEB)

    Weissgerber, Wilfried

    2013-05-01

    The book under consideration covers the basics and calculation methods of the alternating current technology, the transformer, loci diagrams as well as three-phase systems. The book is dedicated to the students of engineering and natural sciences, electrical engineering, technical informatics and physics at higher institutes of applied sciences, technical colleges, universities and universities of cooperative education.

  16. 消除谐波电流的七相感应电机矢量控制%Vector Control of Seven-Phase Induction Motor with Harmonic Currents Elimination

    Institute of Scientific and Technical Information of China (English)

    郭冀岭; 肖建; 邱忠才; 罗鹏

    2014-01-01

    为了实现对七相感应电机磁链和转矩控制,同时消除定子谐波电流,根据减小空间解耦模型谐波子空间中合成电压矢量的原理,提出了3种消除定子谐波电流的方法,即3次谐波子空间合成矢量为0的SVPWM (space vector pulse width module)A法、3次及5次谐波子空间合成矢量同时为0的SVPWM B法和通过电机闭环控制的UVM (unified voltage module)C法.采用负载调速实验验证了3种控制方法对七相感应电机磁链和转矩的控制效果.结果表明:SVPWM A法和SVPWM B法,在调制深度和转速调节过程中,依靠调整施加矢量顺序和作用时间来实现消谐,效果不理想;UVM C法通过增加谐波子空间电压为0的约束条件,实现闭环控制,消除谐波电流效果较好,在基波含量为52.5 dB情况下,3次和5次谐波含量很低,仅为17.8和9.8 dB.%In order to control the flux and torque and eliminate harmonic status currents of seven-phase induction motors simultaneously,three methods were proposed according to the principle of reducing the harmonic subspace composite voltage vectors in the space decomposition model. These methods included the space vector pulse width module (SVPWM)A where the composite voltage vector of the 3rd harmonic subspace is zero,the SVPWM B where the composite voltage vector of the 3rd or the 5th harmonic subspace is zero,and the unified voltage module (UVM)C that adopts a closed-loop motor control strategy. Speed-regulating experiments were then performed to verify the efficiency of the three methods in control of the flux and torque. The results show that the performance on harmonic currents elimination using SVPWM A or SVPWM B is not satisfying,since only the action time and sequence of voltage vectors are adjusted while the modulation depth and motor speed are changing continuously. However,a closed loop control of motor is realized under the constraint that harmonic space

  17. Alternative security

    International Nuclear Information System (INIS)

    This book contains the following chapters: The Military and Alternative Security: New Missions for Stable Conventional Security; Technology and Alternative Security: A Cherished Myth Expires; Law and Alternative Security: Toward a Just World Peace; Politics and Alternative Security: Toward a More Democratic, Therefore More Peaceful, World; Economics and Alternative Security: Toward a Peacekeeping International Economy; Psychology and Alternative Security: Needs, Perceptions, and Misperceptions; Religion and Alternative Security: A Prophetic Vision; and Toward Post-Nuclear Global Security: An Overview

  18. Intrinsic properties of lumbar motor neurones in the adult G127insTGGG superoxide dismutase-1 mutant mouse in vivo: evidence for increased persistent inward currents

    DEFF Research Database (Denmark)

    Meehan, Claire Francesca; Moldovan, Mihai; Marklund, Stefan L.;

    2010-01-01

    of lumbar motoneurones in the adult presymptomatic G127X mutant are not significantly different from those of wild type. However, at more depolarized membrane potentials, motoneurones in the G127X SOD1 mutants can sustain higher frequency firing, showing less spike frequency adaption and with persistent...... inward currents (PICs) being activated at lower firing frequencies and being more pronounced. Conclusion: We demonstrated that, in vivo, at resting membrane potential, spinal motoneurones of the adult G127X mice do not show an increased excitability. However, when depolarized they show evidence...

  19. Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis%基于定子电流法监测无刷直流电动机转子动态偏心的故障模型仿真研究

    Institute of Scientific and Technical Information of China (English)

    赵向阳; 葛文韬

    2011-01-01

    The dynamic eccentricity fault model was implemented and the inductance and flux were resolved based on the finite element method (FEA) on Ansoft/Maxwell. That the simplified fault frequency of monitoring induction motor dynamic eccentricity could be used on brushless DC motor (BLDC) was demonstrated by simulation. The system of brushless DC motor was simulated on Ansoft/Simplorer. In steady state, the Fast Fourier Transform (FFT) analysis was used on the stator current. The simulated model of detecting dynamic eccentricity based on the stator current signature analysis (MCSA) method was investigated and implemented: The frequency to indentify dynamic eccentricity fault, the amplitude of frequency to estimate the dynamic eccentricity severity. Furthermore, the effect of speed pulsation of BLDC operating under steady state was investigated in this article. The results indicate that the severity of dynamic eccentricity fault increase, the amplitude of fault frequency increase.%基于Ansoft/Maxwell设置动态偏心故障,建立求解电机电感和磁链的有限元模型,通过仿真,证明了将感应电机动态偏心故障的特征频率经过简化后,同样适用于无刷直流电动机。基于Ansoft/Simplorer建立无刷直流电动机系统的仿真模型。在电机稳态运行下,对定子电流进行傅里叶分析,研究并建立基于定子电流监测动态偏心故障的仿真模型:动态偏心故障与特征频率的关系、动态偏心故障程度与特征频率幅值的关系。进而研究了无刷直流电动机稳态运行时转速波动对偏心故障监测的影响。仿真结果表明,转子偏心程度加大,特征频率的幅值增加。

  20. 代用燃料汽车技术发展现状及应用前景%Current Development and Application Prospect of Automotive Alternative Fuel Technology

    Institute of Scientific and Technical Information of China (English)

    张宗法

    2012-01-01

    分析了主要代用燃料的类型、特点、存在的问题与应用情况,研究了代用燃料汽车技术的应用现状和发展趋势,讨论了代用燃料汽车应用前景和发展潜力,指出我国汽车应用推广应当走多元化的能源之路。%This paper analyzes the alternative fuel' s main types, characteristics, existing problems and application, researches the application and development tendency of alternative fuel technology. The application prospect and development potential of alternative fuel automobile are discussed in the paper. And then a conclusion is drew that the diversified energy sources must be chosen for vehicle application promotion in China.

  1. Simulation Study on Alternative Current Fault at Inverter Side of Yunnan-Guangdong Ultrahigh Voltage Direct Current Island Operation System%云广直流孤岛系统逆变侧交流故障仿真研究

    Institute of Scientific and Technical Information of China (English)

    刘洪涛; 张勇; 梅勇; 周煜智; 徐政

    2015-01-01

    云广特高压直流孤岛运行时,送端电网短路比和有效惯性常数显著低于联网方式,承受扰动能力较弱。如果逆变侧交流系统发生接地故障导致逆变站换相失败,直流电压和直流功率将大幅降低,引起送端孤岛系统过电压和频率升高。利用 PSCAD/EMTDC 电磁仿真软件,针对云广直流孤岛系统两种典型运行方式,研究了逆变侧交流系统故障对送端孤岛系统的影响。仿真结果表明:逆变侧交流系统故障引起的直流换相失败持续时间越长,整流侧交流系统短路比和有效惯性常数越小,送端孤岛系统受故障影响越严重;云广直流在两种典型孤岛运行方式下,逆变侧交流系统发生故障时,送端孤岛系统都能保持暂态稳定。%Short circuit ratio and effective inertia constant of the sending end grid under island operation mode of Yunnan-Guangdong ultrahigh voltage direct current(UVDC)project is notably lower than that under networking mode which means weak ability to bear turbulence. If commutation of the inverter station fails caused by grounding fault of alternative current (AC)system at the inverter side ,DC voltage and DC power may substantially reduce and cause overvoltage and frequency of the island system at sending end rise. In allusion two typical running modes of Yunnan-Guangdong UVDC island system, PSCAD/EMTDC electromagnetic simulation software was used for studying affect on the island system at sending end by AC system fault at the inverter side. The simulation results indicate that duration time of DC commutation failure is longer caused by AC system fault at the inverter side,short circuit ratio and effective inertia constant at the rectification side is smaller and affect on island system at sending end by the fault is more serious. In addition,under these two typical island op-eration modes,when the AC system at inverter side develops a fault,island system at sending end

  2. Locomotion of chemically powered autonomous nanowire motors

    Science.gov (United States)

    Wang, Lin; Li, Longqiu; Li, Tianlong; Zhang, Guangyu; Sun, Qian

    2015-08-01

    Physical insights on the hydrodynamics and locomotion of self-propelled nanowire motor under nonequilibrium steady state are investigated using finite element method in accordance with hybrid molecular dynamics/multiparticle collision dynamics and rigid body dynamics. Nanowire motor is discretized into finite segments, and forces of solvent molecule acting on the motor are assumed to be the sum of forces acting on all segments of the motor. We show that the locomotion of nanowire motor is mainly determined by the imbalance forces acting on the catalytic and noncatalytic segments. The average velocity along the axis increases significantly as a function of time prior to reaching equilibrium. The length of nanowire motor shows negligible effect on the velocity of the motor. Preliminary experimental results are provided to validate the current model.

  3. Actions to promote energy efficient electric motors. Motors study group

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, A.T. de [Coimbra Univ. (PT). Inst. of Systems and Robotics (ISR)

    1996-10-01

    Motor electricity consumption is influenced by many factors including: motor efficiency, motor speed controls, power supply quality, harmonics, systems oversizing, distribution network, mechanical transmission system, maintenance practices, load management and cycling, and the efficiency of the end-use device (e.g. fan, pump, etc.). Due to their importance, an overview of these factors is presented in this report. This study also describes the electricity use in the industrial and tertiary sectors and the electricity consumption associated with the different types of electric motors systems in the Member States of the European Union, as well as estimated future evolution until 2010. The studies for individual countries were carried out by the different partners of the motors study group at a previous stage. The study has found that there is a lack of accurate information about the motor electricity consumption, installed motor capacity and the motor market in almost all the European Union countries and only some general statistical sources are available. There is little field data, which is mainly available in Denmark, France, Italy and the Netherlands. Due to this lack of primary information, some common assumptions were made, based on the experience of the members of the study group. This lack of end-use characterisation data shows the need for improvement from the point of view of current knowledge. It is therefore recommended that further research is undertaken to arrive at more accurate figures. These could be the basis for a better understanding for motor use in practice and - as a consequence - for a more precise appraisal of potentials and barriers to energy efficiency. (orig.)

  4. Line start permanent magnet synchronous motors: Challenges and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Hassanpour Isfahani, Arash; Vaez-Zadeh, Sadegh [School of Electrical and Computer Engineering, Faculty of Engineering, University of Tehran, North Kargar Ave., P.O. Box: 14395/515, Tehran (Iran)

    2009-11-15

    Future energy challenges, likewise the environmental crises such as fossil fuel emissions and global warming urge the world to focus on energy saving programs more than ever. An effective way to face these challenges is to improve electric motors efficiency as one of the greatest energy consumption apparatuses in the world. Induction motors constitute, by far, the largest portion of electric motors both in terms of quantity and total power ratings among all electric motors. However, more efficient motor types gradually appear as alternatives. In this paper, line start permanent magnet motors as a powerful candidate with growing market are investigated in some details. The motor opportunities like high efficiency, high power factor and high power density are explored against the challenges associated with this motor including higher cost, extra manufacturing burden and transient and synchronization behaviors. Finally, some concluding comments and remarks are drawn for future research and manufacturing of line start permanent magnet motors. (author)

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

    Directory of Open Access Journals (Sweden)

    Y.Narendra Kumar,

    2014-04-01

    Full Text Available 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 as an alternative for traditional motors like induction and switched reluctance motors. In this paper PID controller is implemented with speed feedback loop and it is observe that torque ripples are minimized. Simulation is carried out using MATLAB / SIMULINK. The results show that the performance of BLDC Motor is quite satisfactory for various loading conditions. Brushless DC motor drives are typically employed in speed controlled applications.

  6. 76 FR 17577 - Increased Scope of Coverage for Electric Motors

    Science.gov (United States)

    2011-03-30

    ... torque, pull-up torque, breakdown torque, inrush current, and locked-rotor current.) These motors are identical except with respect to the limit on inrush current \\2\\--Design B motors are limited to certain...\\ Inrush current refers to the maximum, instantaneous input current drawn by an electrical device...

  7. Differential effects of cathodal transcranial direct current stimulation of prefrontal, motor and somatosensory cortices on cortical excitability and pain perception - a double-blind randomised sham-controlled study.

    Science.gov (United States)

    Vaseghi, B; Zoghi, M; Jaberzadeh, S

    2015-10-01

    The primary aim of this study was to assess the effects of cathodal transcranial direct current stimulation (c-tDCS) over cortical regions of the pain neuromatrix, including the primary motor (M1), sensory (S1) and dorsolateral prefrontal (DLPFC) cortices on M1/S1 excitability, sensory (STh), and pain thresholds (PTh) in healthy adults. The secondary aim was to evaluate the placebo effects of c-tDCS on induced cortical and behavioural changes. Before, immediately after and 30 min after c-tDCS the amplitude of N20-P25 components of somatosensory evoked potentials (SEPs) and peak-to-peak amplitudes of motor evoked potentials (MEPs) were measured under four different experimental conditions. STh and PTh for peripheral electrical and mechanical stimulation were also evaluated. c-tDCS of 0.3 mA was applied for 20 min. A blinded assessor evaluated all outcome measures. c-tDCS of M1, S1 and DLPFC significantly decreased the corticospinal excitability of M1 (P SEPs decreased for at least 30 min (P < 0.05). Compared with baseline values, significant STh and PTh increases were observed after c-tDCS of these three sites. Decreasing the level of S1 and M1 excitability, following S1, M1 and DLPFC stimulation, confirmed the functional connectivities between these cortical sites involved in pain processing. Furthermore, increasing the level of STh/PTh after c-tDCS of these sites indicated that stimulation of not only M1 but also S1 and DLPFC could be considered a technique to decrease the level of pain in patients. PMID:26275236

  8. Alternative energies; Energies alternatives

    Energy Technology Data Exchange (ETDEWEB)

    Bonal, J.; Rossetti, P

    2007-07-01

    The earth took millions years to made the petroleum, the gas the coal and the uranium. Only a few centuries will be needed to exhaust these fossil fuels and some years to reach expensive prices. Will the wold continue on this way of energy compulsive consumption? The renewable energies and some citizen attitudes are sufficient to break this spiral. This book proposes to discuss these alternative energies. It shows that this attitude must be supported by the government. It takes stock on the more recent information concerning the renewable energies. it develops three main points: the electricity storage, the housing and the transports. (A.L.B.)

  9. 步进驱动器高压恒流过程与参数计算%High-Voltage Constant-Current Process and Parameter Calculation for Stepper Motor Drives

    Institute of Scientific and Technical Information of China (English)

    张文明

    2011-01-01

    To solve the problem of torque decrease at low or high speed,a new three-phase hybrid stepper motor drive was developed. All the hardware circuit and software program of the drive were presented. With the new device,the hardware circuit parameters,critical data and software design were analyzed in detail. Meanwhile a comprehesive explanation of the PLC,logic control,constant cruuent control,high voltage drive,current sampling,over current protection and power supply ciruit was put forward, which is of a certain reference value.%针对步进电动机在低速和高速转矩下降的问题,开发出一种新型三相混合式步进电动机驱动器.给出驱动器全部硬件电路和软件程序,结合新器件应用,对硬件电路参数、关键数据、软件设计进行详实分析,全面剖析了单片机、逻辑控制、恒流控制、高压驱动、电流采样、过压保护、供电电源电路等,具有一定参考价值.

  10. THE MOTOR

    DEFF Research Database (Denmark)

    Gammelgaard Nielsen, Anders

    2011-01-01

    MOTOR is the first assignment that students at Unit 1a of the School of Architecture are introduced to. The purpose of the assignment is to shake up the students and their preconceptions of what architec- ture is. This is done by introducing them to a working method that al- lows them to develop...... architecture that resides beyond their own imag- inative capabilities. In other words the core aim of the assignment is to equip students with an understand- ing that architecture can be devel- oped through a predetermined ge- neric process and that through this process opportunities exist to devel- op...... something original and genuine that decisively challenges the limits of the field of architecture. This un- derstanding is important if students are to avoid mimicking an existing world of imagery in architecture or fragments of it. The point of departure for the MO- TOR assignment is that a car engine...

  11. Motor Neuron Diseases

    Science.gov (United States)

    ... Awards Enhancing Diversity Find People About NINDS Motor Neuron Diseases Fact Sheet See a list of all ... can I get more information? What are motor neuron diseases? The motor neuron diseases (MNDs) are a ...

  12. Using the motor to monitor pump conditions

    Energy Technology Data Exchange (ETDEWEB)

    Casada, D. [Oak Ridge National Lab., TN (United States)

    1996-12-01

    When the load of a mechanical device being driven by a motor changes, whether in response to changes in the overall process or changes in the performance of the driven device, the motor inherently responds. For induction motors, the current amplitude and phase angle change as the shaft load changes. By examining the details of these changes in amplitude and phase, load fluctuations of the driven device can be observed. The usefulness of the motor as a transducer to improve the understanding of devices with high torque fluctuations, such as positive displacement compressors and motor-operated valves, has been recognized and demonstrated for a number of years. On such devices as these, the spectrum of the motor current amplitude, phase, or power normally has certain characteristic peaks associated with various load components, such as the piston stroke or gear tooth meshing frequencies. Comparison and trending of the amplitudes of these peaks has been shown to provide some indication of their mechanical condition. For most centrifugal pumps, the load fluctuations are normally low in torque amplitude, and as a result, the motor experiences a correspondingly lower level of load fluctuation. However, both laboratory and field test data have demonstrated that the motor does provide insight into some important pump performance conditions, such as hydraulic stability and pump-to-motor alignment. Comparisons of other dynamic signals, such as vibration and pressure pulsation, to motor data for centrifugal pumps are provided. The effects of inadequate suction head, misalignment, mechanical and hydraulic unbalance on these signals are presented.

  13. Fine motor skill performance in Irish children

    OpenAIRE

    Gaul, David

    2014-01-01

    Background Motor skills are the basis for any bodily movement. They allow children to read, write, walk, talk and play sports. These skills play a central role in children's lives and specifically allow them to be physically active and healthy. However there is currently a lack of knowledge in relation to the level of fine motor skills in children both in Ireland and internationally. Fine motor skills are an essential component of numerous activities of daily life such as dressing and feed...

  14. Alternative additives; Alternative additiver

    Energy Technology Data Exchange (ETDEWEB)

    2007-08-15

    In this project a number of industrial and agricultural waste products have been characterised and evaluated in terms of alkali-getter performance. The intended use is for biomass-fired power stations aiming at reducing corrosion or slagging related problems. The following products have been obtained, characterised and evaluated: 1) Brewery draff 2) Danish de-gassed manure 3) Paper sludge 4) Moulding sand 5) Spent bleaching earth 6) Anorthosite 7) Sand 8) Clay-sludge. Most of the above alternative additive candidates are deemed unsuitable due to insufficient chemical effect and/or expensive requirements for pre-treatment (such as drying and transportation). 3 products were selected for full-scale testing: de-gassed manure, spent bleaching earth and clay slugde. The full scale tests were undertaken at the biomass-fired power stations in Koege, Slagelse and Ensted. Spent bleaching earth (SBE) and clay sludge were the only tested additive candidates that had a proven ability to react with KCl, to thereby reduce Cl-concentrations in deposits, and reduce the deposit flux to superheater tubes. Their performance was shown to nearly as good as commercial additives. De-gassed manure, however, did not evaluate positively due to inhibiting effects of Ca in the manure. Furthermore, de-gassed manure has a high concentration of heavy metals, which imposes a financial burden with regard to proper disposal of the ash by-products. Clay-sludge is a wet clay slurring, and drying and transportation of this product entails substantial costs. Spent bleaching does not require much pre-treatment and is therefore the most promising alternative additive. On the other hand, bleaching earth contains residual plant oil which means that a range of legislation relating to waste combustion comes into play. Not least a waste combustion fee of 330 DKK/tonne. For all alternative (and commercial) additives disposal costs of the increase ash by-products represents a significant cost. This is

  15. Alternative strategies to prevent and control endoparasite diseases in organic sheep and goat farming systems – a review of current scientific knowledge

    OpenAIRE

    Rahmann, Gerold (Ed.); Seip, Hannah

    2006-01-01

    Infestation with gastro-intestinal nematodes in small ruminants can cause server economic losses and endanger animal welfare. The development of organic farming systems, the increased public awareness for drug residues in agricultural products and the development of resistant strains of parasites have enforced the search for sustainable alternatives. The aim of this paper was to provide information about endoparasite infecting small ruminants, to give an overview of the legal background and t...

  16. 脉冲交变磁场测量技术缺陷识别与定量评估%Pulsed Alternating Current Field Measurement Technique for Defect Identification and Quantification

    Institute of Scientific and Technical Information of China (English)

    胡祥超; 罗飞路; 何赟泽; 唐莺

    2011-01-01

    传统的交变磁场测量(Alternating current field measurement,ACFM)技术具有缺陷定量准确、无需接触等优点,但是不能检测深层缺陷;脉冲涡流检测技术(Pulsed eddy current testing,PECT)具有较好的深层缺陷检测能力,但由于采用瞬态响应信号分析方法,容易受到提离效应干扰,工程实际应用较为困难,并且定量能力弱于ACFM技术.结合ACFM和PECT的优势,提出了脉冲交变磁场测量技术(Pulsed alternating current field measurement,PACFM).该技术采用脉冲周期信号作为激励信号源,基于瞬态脉冲响应信号,采用三维场量测量和瞬态信号分析相结合的方法实现缺陷识别与定量评估.对瞬态响应信号中能够表征磁场变化规律的特征量进行提取,通过研究发现PACFM不仅具有与ACFM等同的表面缺陷检测能力,而且具有优异的深层缺陷识别与定最评估能力,抗干扰能力强,具有较高的应用价值和前景.%Traditional alternating current field measurement (ACFM) technique has advantages of quantitative defect detection and noncontact, but poor detective performances on deep-layer defects. Pulsed eddy current testing (PECT) has a better detectability in deep-layer defect, but poorer quantitative performances than ACFM, and moreover, it is easily interfered by lift-off due to using transient response signal analysis method so it is difficult to be applied practically. A method of alternating current filed measurement with pulsed signal excitation is proposed, which implements defect detection and quantitative evaluation by approach of transient signal analysis combined with 3D magnetic filed measurement based on pulsed response signal. Characteristics in the transient response signal which can reflect the variation law of magnetic field are extracted. Through the study it is found that the pulsed alternating current field measurement has not only the same detectability of surface defects as ACFM, but also an

  17. Alternative crops

    International Nuclear Information System (INIS)

    Surplus cereal production in the EEC and decreasing product prices, mainly for cereals, has prompted considerable interest for new earnings in arable farming. The objective was to examine whether suggested new crops (fibre, oil, medicinal and alternative grains crops) could be considered as real alternatives. Whether a specific crop can compete economically with cereals and whether there is a market demand for the crop is analyzed. The described possibilities will result in ca. 50,000 hectares of new crops. It is expected that they would not immediately provide increased earnings, but in the long run expected price developments are more positive than for cereals. The area for new crops will not solve the current surplus cereal problem as the area used for new crops is only 3% of that used for cereals. Preconditions for many new crops is further research activities and development work as well as the establishment of processing units and organizational initiatives. Presumably, it is stated, there will then be a basis for a profitable production of new crops for some farmers. (AB) (47 refs.)

  18. Five phase hybrid stepping motor microstepping control

    Directory of Open Access Journals (Sweden)

    Zsolt Albert Barabas

    2014-12-01

    Full Text Available Single stepping a motor results in jerky movements of the motor, especially at lower speeds. Microstepping is used to achieve increased step resolution and smoother transitions between steps. In most applications, microstepping increases system performance while limiting noise and resonance problems. The paper presents a method for calculation the values of the phase currents for microstepping control of a 5 – phase hybrid stepping motor. This method uses the standard control of the stepping motor with rated currents and only during the commutation the currents of the switched phases change their values in small steps so as the natural step is divided into several micro – steps. The authors have developed a mathematical model and computer programs for simulation of the motor operation under investigated microstepping control. The paper contains also the results from simulations and corresponding conclusions.

  19. 非正弦交变励磁电流峰值与试件磁化关系的讨论%Discussion on the Relationship Between Non-Sinusoidal Alternate Exciting Current Peak Value and Sample Magnetization

    Institute of Scientific and Technical Information of China (English)

    林锡忠

    2012-01-01

    论述了磁粉探伤中,当用可控硅产生非正弦交变(50Hz)电流励磁时,磁化的效果仍取决于励磁电流的峰值。%It was' described that magnetizing effect was dependent on exciting current(50 Hz) peak value during using silicon control generate non-sinusoidal alternately current in magnetic particle testing.

  20. 智能斜极面交流接触器动态优化设计与分析%Dynamic Optimization Design and Analysis for Intelligent Inclined Surface Alternating Current Contactor

    Institute of Scientific and Technical Information of China (English)

    鲍光海; 张培铭

    2011-01-01

    采用ANSYS电磁场分析软件与基于遗传算法的人工鱼群优化算法对智能平极面交流接触器进行以快速分断、提高零电流分断准确性与稳定性为目标的动态优化计算,并验证了优化算法的正确性.考虑到斜极面交流电磁系统的优越性,对平极面交流接触器与斜极面交流接触器静态特性进行比较分析,提出了智能斜极面交流接触器的结构方案.根据上述优化算法,对智能斜极面交流接触器进行了智能动态优化设计.优化结果表明:智能斜极面交流接触器与智能平极面交流接触器相比,其用铜量减小45%,用铁量减小23%,而且具有更好的动态特性、更高的零电流分断准确性与稳定性.%We conducted dynamic optimized calculation of electromagnetic mechanism for the goal of breaking quickly and zero current break stability by using artificial fish swarm optimization algorithm based on genetic algorithm, and verifies the validity of optimization algorithm. According to the advantage of inclined surface alternating current contactor, the proposal of intelligent inclined surface alternating current contactor was proposed. The method of intelligent dynamic optimization design was used to optimization design the intelligent inclined surface alternating current contactor base on the previous optimized algorithm. The optimization results showed that the coil volume of intelligent incline surface alternating current contactor decrease 45% than that of flat surface,and the iron core volume decrease 23 %. Moreover, its dynamic characteristics were better than those of intelligent flat surface alternating current contactor.

  1. Designing velocity modulation and measuring system of direct current motor based on the DSP%基于DSP的直流电机调速、测速系统设计

    Institute of Scientific and Technical Information of China (English)

    王惠平

    2011-01-01

    To realize the control function of velocity modulation and measuring of direct current motor,the platform of TMS320LF2407A model DSP was used to develop a 24V control system based on digital PWM principle.The system can be connected to a computer with simple serial port software.The electrical circuit is simple,reliable and practical.%为了精确实现直流电机调速、测速等控制功能,文中利用TMS320LF2407A型号的DSP实验平台,以数字PWM对直流电机调速为控制原理,构建了一个24V直流电机控制系统,且可通过一个简单的串口软件实现电脑输入调节,通过设计本系统较精确的实现了电机调速、测速和串口通信显示等功能,该设计方案电路简单、可靠性强,具有较高的应用价值。

  2. 电流型多相永磁同步电动机调速系统的换相转矩脉动%Commutation Torque Ripple Analysis of Current-Type Multiphase Permanent Magnet Synchronous Motor Speed Control System

    Institute of Scientific and Technical Information of China (English)

    周羽; 李槐树; 苏广东

    2013-01-01

    为了研究多相梯形波永磁同步电动机(以下简称TPMSM)的换流转矩脉动,基于Y-Y移30°电角度的六相TPMSM建立电流型调速系统的数学模型,给出了换流重叠角的计算公式,并利用仿真分析了换相超前角和换流重叠角之间的关系以及换相超前角和转矩脉动之间的关系.结果表明,减小换相超前角有利于减小转矩脉动,但是会增加换流重叠角,甚至导致换流失败.%In order to study the commutation torque ripple of multiphase trapezia-wave permanent magnet synchronous motor (TPMSM) ,the mathematical model of current-type speed control system was established based on the six-phase TPMSM with Y-Y winding shifting 30° electric-degree. The calculating formula of commutating angular overlap was given. And the relationship of commutating angle and commutating angular overlap and relationship of commutating angular overlap and torque ripple were analyzed. The results show that reducing commutating angle is beneficial to reducing torque ripple, but it will increase commutating angular overlap,even bring on the failure of commutation.

  3. Designing an intelligent system to predict drill wear by using of motor current and fuzzy logic method - doi: 10.4025/actascitechnol.v35i4.15647

    Directory of Open Access Journals (Sweden)

    Aydin Salimi

    2013-10-01

    Full Text Available In automation flexible manufacturing systems, tool wear detection during the cutting process is one of the most important considerations. This study presents an intelligent system for online tool condition monitoring in drilling process. In this paper, analytical and empirical models have been used to predict the thrust and cutting forces on the lip and chisel edges of a new drill. Also an empirical model is used to estimate tool wear rate and force values on the edges of the worn drill .By using the block diagram of machine tool drives, the changes in the feed and spindle motor currents are simulated, as wear rate increases. To predict tool wear rate, fuzzy logic capabilities have been used to develop an intelligent system. The simulation results presented with MATLAB software show the effectiveness of proposed system for on-line drill wear monitoring. This is confirmed by comparing the measured and estimated values with each other in which the value of R2 was obtained 0.9367 in the regression graph.  

  4. High efficiency motors; Motores de alta eficiencia

    Energy Technology Data Exchange (ETDEWEB)

    Uranga Favela, Ivan Jaime [Energia Controlada de Mexico, S. A. de C. V., Mexico, D. F. (Mexico)

    1992-12-31

    This paper is a technical-financial study of the high efficiency and super-premium motors. As it is widely known, more than 60% of the electrical energy generated in the country is used for the operation of motors, in industry as well as in commerce. Therefore the importance that the motors have in the efficient energy use. [Espanol] El presente trabajo es un estudio tecnico-financiero de los motores de alta eficiencia y los motores super premium. Como es ampliamente conocido, mas del 60% de la energia electrica generada en el pais, es utilizada para accionar motores, dentro de la industria y el comercio. De alli la importancia que los motores tienen en el uso eficiente de la energia.

  5. Free Energy Transduction in a Chemical Motor Model

    CERN Document Server

    Baker, J E

    2003-01-01

    Motor enzymes catalyze chemical reactions, like the hydrolysis of ATP, and in the process they also perform work. Recent studies indicate that motor enzymes perform work with specific intermediate steps in their catalyzed reactions, challenging the classic view (in Brownian motor models) that work can only be performed within biochemical states. An alternative class of models (chemical motor models) has emerged in which motors perform work with biochemical transitions, but many of these models lack a solid physicochemical foundation. In this paper, I develop a self consistent framework for chemical motor models. This novel framework accommodates multiple pathways for free energy transfer, predicts rich behaviors from the simplest multi motor systems, and provides important new insights into muscle and motor function.

  6. Premium Efficiency Motor Selection and Application Guide – A Handbook for Industry

    Energy Technology Data Exchange (ETDEWEB)

    Gilbert A. McCoy and John G. Douglass

    2014-02-01

    This handbook informs new motor purchase decisions by identifying energy and cost savings that can come from replacing motors with premium efficiency units. The handbook provides an overview of current motor use in the industrial sector, including the development of motor efficiency standards, currently available and emerging advanced efficiency motor technologies, and guidance on how to evaluate motor efficiency opportunities. It also several tips on getting the most out of industrial motors, such as how to avoid adverse motor interactions with electronic adjustable speed drives and how to ensure efficiency gains are not lost to undervoltage operation or excessive voltage unbalance.

  7. Complicaciones respiratorias de la tetraplejia: Una mirada a las alternativas terapéuticas actuales Respiratory complications in tetraplegia: Overview to current therapeutic alternatives

    Directory of Open Access Journals (Sweden)

    DANIELA GARCÍA P

    2007-06-01

    Full Text Available Las complicaciones respiratorias son la principal causa de muerte en los pacientes con tetraplejia, tanto en el período agudo como crónico. En esta categoría se incluyen diversas alteraciones como neumonías recurrentes, atelectasias, mal manejo de las secreciones, insuficiencia respiratoria e hipoventilación. Además, son frecuentes patologías más complejas como el tromboembolismo pulmonar y la apnea obstructiva del sueño. Se postula que las causas principales de los problemas respiratorios son la debilidad de los músculos intercostales y abdominales, y la disfunción parcial o total del diafragma. Hoy en día existen múltiples alternativas terapéuticas para prevenir, manejar y tratar en forma específica las diversas complicaciones. El propósito de este artículo es revisar las opciones terapéuticas actualmente vigentes y despertar el interés entre los clínicos para profundizar más en este importante temaRespiratory complications are the first cause of death in patients with tetraplegia, including both the acute and chronic stage of the disease. They include a wide variety of respiratory problems, such as repeated pneumonias, atelectasis, unsatisfactory secretions manage, respiratory failure, hypoventilation, and other complex pathologies such as pulmonary embolism and sleep apnea syndrome. It has been postulated that the main cause of all these respiratory complications is weakness of inter costáis and abdominal muscles, and partial or complete dysfunction of the diaphragm. Today we have multiple therapeutic alternatives to prevent, manage and specifically treat the multiple types of complications. The main objective of this article is to review the different therapeutical alternatives and encourage the study of this important topic

  8. Motor Priming in Neurorehabilitation

    OpenAIRE

    Stoykov, Mary Ellen; Madhavan, Sangeetha

    2015-01-01

    Priming is a type of implicit learning wherein a stimulus prompts a change in behavior. Priming has been long studied in the field of psychology. More recently, rehabilitation researchers have studied motor priming as a possible way to facilitate motor learning. For example, priming of the motor cortex is associated with changes in neuroplasticity that are associated with improvements in motor performance. Of the numerous motor priming paradigms under investigation, only a few ...

  9. 飞轮储能用高速永磁电机转子的涡流损耗%Rotor eddy current loss in high speed permanent magnet motors for flywheel energy storage system

    Institute of Scientific and Technical Information of China (English)

    田占元; 祝长生; 王玎

    2011-01-01

    为了减小高速永磁电机中由定子电流的时间谐波、定子磁动势的空间谐波以及定子槽开口造成的气隙磁导变化引起的转子涡流损耗,提高电机的效率,采用ANSOFT有限元软件分析了高速永磁电机中气隙磁场和定子电流.研究了槽开口大小以及气隙长度对转子涡流损耗的影响,分析了利用涡流磁场的屏蔽作用,提出在永磁体外增加一薄层非导磁金属屏蔽环来减小转子铁心、永磁体和护套损耗的机理和有效性,以及屏蔽环的电导率和厚度对转子涡流损耗的影响.结果表明:在合理选取槽开口大小、气隙长度和非导磁金属屏蔽环电导率和厚度的情况下,添加非导磁金属屏蔽环可以有效地减小转子涡流损耗.%In order to reduce the rotor eddy current loss, which is mainly caused by temporal harmonics in the excitation current, spatial harmonics in the pulsating stator magnetic motive force, and the airgap permeance variation due to slot-openings, and improve the efficiency of high speed permanent magnet motor,the spatial harmonics of the airgap flux density and the temporal harmonics of the excitation current were first analyzed by ANSOFT software, The influences of slot opening width and airgap length on the rotor eddy current loss were studied considering the skin effect. The mechanism and the effectiveness of a thin unmagnetized metal shielding ring around the magnets, which uses the shielding effect of the eddy current magnetic field, to reduce the eddy current loss in the rotor core, the magnets, and the retaining sleeve were analyzed. The effects of the electrical conductivity and thickness of the shielding ring on the rotor eddy current loss were analyzed. The results show that a thin unmagnetized metal shielding ring around the magnets only with a properly chosen slot opening width, airgap length, electrical conductivity and thickness of the shielding ring can significantly reduce the total eddy

  10. Improved Rotor Speed Brushless DC Motor Using Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Jafar Mostafapour

    2015-04-01

    Full Text Available A brushless DC (BLDC Motors have advantages over brushed, Direct current (DC Motors and , Induction motor (IM. They have better speed verses torque characteristics, high dynamic response, high efficiency, long operating life, noiseless operation, higher speed ranges, and rugged construction. Also, torque delivered to motor size is higher, making it useful in application where space and weight are critical factors. With these advantages BLDC motors find wide spread application in automotive appliance, aerospace medical, and instrumentation and automation industries This paper can be seen as fuzzy controllers compared to PI control BLDC motor rotor speed has improved significantly and beter result can be achieve.

  11. Biofuel as an alternative to oil——current industry progress and sustainable development%生物燃料替代石油——产业现状与可持续发展

    Institute of Scientific and Technical Information of China (English)

    李十中

    2011-01-01

    As modern transport has provided facilities to people' s lives, it has triggered significant air pollution and oil depletion in the meanwhile. For the purpose of a sustainable social-economic development, biofuel is the most viable alternative to oil, as well as the best option. This paper summarizes research and practice development process of biofuel, with a focus on the application as motor fuel and aviation fuel. Also, proposed strategies and their significance about biofuel development in China are also presented in this study.%文章分析了用生物燃料替代石油以实现控制全球气候变化、减少石油消耗和环境污染、创造就业机会,实现社会经济的可持续发展的重要性;介绍了国内外生物燃料产业发展历程和趋势,以及在汽车燃料和航空燃料领域的应用现状,提出了我国当前发展生物燃料的战略和对策.

  12. Complementary/Alternative therapies for the treatment of breast cancer. A systematic review of randomized clinical trials and a critique of current terminology.

    Science.gov (United States)

    Ernst, Edzard; Schmidt, Katja; Baum, Michael

    2006-01-01

    The objectives of this study was to evaluate and critically analyze all randomized clinical trials (RCTs) of ''alternative cancer cures'' (ACCs) for breast cancer. The electronic databases Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, Allied and Complementary Medicine, Scirus, BIOSIS, CancerLit and CINAHL and for ongoing trials the MetaRegister at http://www.controlled-trials.com/ and the National Research Register at http://www.update-software.com/national/ were searched from their inception. Bibliographies of located studies were scanned. Unpublished or ongoing trials were identified through correspondence with experts in the field. Our own files were hand searched for further RCTs. Review methods included a systematic review of RCTs involving breast cancer patients treated with ACCs, survival, parameters indicative of tumor burden, disease progression, cancer recurrence, and cancer cure. Results were tabulated and summarized. Thirteen RCTs met the inclusion criteria. In most cases their methodological quality is low, with only two RCTs scoring ''4'' and four RCTs scoring ''3'' out of 5 possible points for methodological quality. The treatments tested included various methods of psychosocial support such as group support therapy, cognitive behavioral therapy cognitive existential group therapy, a combination of muscle relaxation training and guided imagery, the Chinese herbal remedy Shi Quan Da Bu Tang, thymus extract, transfer factor, melatonin, and factor AF2. Encouraging but not fully convincing results emerged for melatonin. PMID:17238981

  13. Current source inverter fed electric vehicle motor drive system with high performance%电动汽车用高性能电流型trans-Z源逆变器特性研究

    Institute of Scientific and Technical Information of China (English)

    郭强; 刘和平; 彭东林

    2015-01-01

    Considering the tougher standards on operation temperature and reliability, an electric vehicle ( EV) motor drive system based on current-fed trans-Z source inverter was presented. The inverter is a single-stage topology, which has Buck-Boost characteristic and achieves bidirectional power flow. The drive system can overcome the drawbacks of the traditional EV drives. It can realize output voltage range from 0 to any times of battery voltage,requires no DC bus capacitors, and provides sinusoidal voltage out-put to the motor, reduces the inverter cost and the failure rate. The different operation states and the e-quivalent circuits of the system were elaborated. The mapping relationship of multi-degrees of control freedom between duty ratios of open-zero states, non-open states and DC-link voltage gain was estab-lished. The available range for different operation modes was discussed, and ac voltage of inverter versus modulation index and power factor was clarified. A prototype of current-fed trans-Z-source inverter was built,the experimental results were presented to verify the theoretical analysis.%鉴于对电动汽车驱动系统运行温度及可靠性的严格要求,提出基于高性能电流型trans-Z源逆变器电机驱动系统,其拓扑是一种具有升-降压功能的单级逆变器,具有能量双向流动的特点。该系统能够克服传统驱动系统中缺点与不足:具有输出电压的任意升-降压功能;无需直流母线电容,提供正弦驱动电压,同时降低了硬件成本、提高了整个驱动系统的可靠性。文中详细分析了系统工作原理并推导出不同运行模式的等效电路,建立多自由度控制下直通零状态、开路零状态与直流链电压增益的映射关系;明确了系统在不同模式下的运行范围,量化逆变器输出电压与控制变量及功率因数之间的关系。最后通过实验验证了理论分析的正确性与实用性。

  14. A Humanized Clinically Calibrated Quantitative Systems Pharmacology Model for Hypokinetic Motor Symptoms in Parkinson’s Disease

    OpenAIRE

    Roberts, Patrick; Spiros, Athan; Geerts, Hugo

    2016-01-01

    The current treatment of Parkinson’s disease with dopamine-centric approaches such as L-DOPA and dopamine agonists, although very successful, is in need of alternative treatment strategies, both in terms of disease modification and symptom management. Various non-dopaminergic treatment approaches did not result in a clear clinical benefit, despite showing a clear effect in preclinical animal models. In addition, polypharmacy is common, sometimes leading to unintended effects on non-motor cogn...

  15. Bulanık Kazanç Ayarlamalı Nonlineer PI Kontrolörün Kalıcı Mıknatıslı Doğru Akım Motor-Dinamo Sistemine Uygulanması = Applying the Fuzzy Gain Scheduling Nonlinear PI Controller to Permanent Magnet Direct Current Motor - Dynamo System

    Directory of Open Access Journals (Sweden)

    Kamil Burak DALCI

    2004-01-01

    Full Text Available This paper describes the realization of a fuzzy gain scheduling scheme of a PI controller using a RISC microcontroller. Fuzzy rules and reasoning are utilised on-line to determine the PI controller parameters based on the error signal and its first difference. The Fuzzy control algorithm is implemented in the RISC microcontroller to regulate the speed of a permanent magnet DC motor (PMDC and works on-line. The microcontroller directly tunes the motor speed with a chopper converter which changes the motor terminal voltage. Application results demonstrate that better control performance can be achieved in comparison with traditional PI controllers.

  16. Nb-Ti base high-field superconductors with current capacities in excess of 3000 A for application in magnet systems with alternating field components

    International Nuclear Information System (INIS)

    Monolithical and fully transposed conductors with current capacities of up to 1000 A at 5 T and 4.2 K as well as measurement methods are described. For conductor technology, extrusion as well as bundling and sealing methods have been developed and tested, a number of different conductors with different substrate amounts and combinations with high-resistivity substrate have been produced and optimized. Fully transposed conductors have been developed as flat cables. A process for continuous soldering and an equipment for soldering cables have been developed and set up. (orig.)

  17. Calculation of alternating current losses in stacks and coils made of second generation high temperature superconducting tapes for large scale applications

    DEFF Research Database (Denmark)

    Zermeno, Victor M. R.; Abrahamsen, Asger Bech; Mijatovic, Nenad;

    2013-01-01

    A homogenization method to model a stack of second generation High Temperature Superconducting tapes under AC applied transport current or magnetic field has been obtained. The idea is to find an anisotropic bulk equivalent for the stack such that the geometrical layout of the internal alternatin...... to be considered. The method presented here allows for a computational speedup factor of up to 2 orders of magnitude when compared to full 2-D simulations taking into account the actual dimensions of the stacks without compromising accuracy....

  18. A Review of the Non-Motoric Visual Gestalt Test and a Comparison with the Bender Visual-Motor Gestalt Test.

    Science.gov (United States)

    Elovitz, Gerald P.

    1979-01-01

    Measures of visual perception, such as the Bender Visual-Motor Gestalt Test (BVMGT) usually require motoric responding, i.e., drawing of figures. An alternative test, the Non-Motoric Visual Gestalt Test (NVGT), is compared with the BVMGT and shown to be superior in measuring visual-perceptual abilities that can discriminate poor and average…

  19. Sensorless Speed Control of Traveling Wave Ultrasonic Motor

    OpenAIRE

    Flückiger, Markus; Bullo, Matteo; Perriard, Yves

    2006-01-01

    Ultrasonic motors are a good alternative to electromagnetic motors in medical robotics, since they are electromagnetically compatible. Estimating speed instead of using encoders reduces cost and dimension of the robot on the one hand and increases reliability on the other hand. However, no sensorless speed controller is yet industrialized. Analytical models of the traveling wave ultrasonic motor being too complex to be exploited for sensorless control purpose, we suggest speed estimation base...

  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. Reluctance motors with bulk HTS material

    International Nuclear Information System (INIS)

    In recent years we have successfully designed, built and tested several reluctance motors with YBCO bulk material incorporated into the rotor, working at 77 K. Our last motor type SRE150 was tested up to 200 kW. The aim of our investigations is the construction of motors with extremely high power density and dynamics. In comparison to conventional motor types the advantage of HTS reluctance motors with respect to size and dynamics could be demonstrated. Some fields of possible future applications will be described. These motors show a significant improvement in performance using high quality HTS bulk elements in the rotor. Until now the motor parameters have been limited by the current density which could be obtained in the bulk material at 77 K and by the geometric dimensions of the segments available. Therefore we expect further improvements in the case of these materials. Since the total motor including stator and rotor is working at low temperature we have to optimize the windings and the magnetic circuit to these operation conditions. A new design of a 200 kW motor in order to achieve increased power density and the theoretical results of our calculations will be shown

  2. Improvement of superconducting cylindrical linear induction motor; Chodendo entokeitan ichiji rinia yudo mota no tokusei kaizen

    Energy Technology Data Exchange (ETDEWEB)

    Kikuma, T.; Tomita, M.; Ishiyama, A. [Waseda Univ., Tokyo (Japan)

    1999-11-10

    For the purpose of we examining the effect of characteristics and ac loss under real machine operating environment of the alternating current superconductivity winding for a realization of the superconductive AC machine vessel, cylindrical shortness first linear guiding motor which used NbTi/CuNi superconducting cable for the primary winding was produced experimentally. The coil number was increased from 6 in 14 this time, and the optimization of the primary current was done, and the improvement on characteristics was attempted. Here, starting torque characteristics, quenching detection protection control circuit are reported. (NEDO)

  3. Electric motor handbook

    CERN Document Server

    Chalmers, B J

    2013-01-01

    Electric Motor Handbook aims to give practical knowledge in a wide range of capacities such as plant design, equipment specification, commissioning, operation and maintenance. The book covers topics such as the modeling of steady-state motor performance; polyphase induction, synchronous, and a.c. commutator motors; ambient conditions, enclosures, cooling and loss dissipation; and electrical supply systems and motor drives. Also covered are topics such as variable-speed drives and motor control; materials and motor components; insulation types, systems, and techniques; and the installation, sit

  4. Directed flux motor

    Science.gov (United States)

    Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

    2011-01-01

    A directed flux motor described utilizes the directed magnetic flux of at least one magnet through ferrous material to drive different planetary gear sets to achieve capabilities in six actuated shafts that are grouped three to a side of the motor. The flux motor also utilizes an interwoven magnet configuration which reduces the overall size of the motor. The motor allows for simple changes to modify the torque to speed ratio of the gearing contained within the motor as well as simple configurations for any number of output shafts up to six. The changes allow for improved manufacturability and reliability within the design.

  5. Motor learning as a criterion for evaluating coordination motor abilities

    Directory of Open Access Journals (Sweden)

    Boraczynski Tomasz

    2011-10-01

    Full Text Available The aim of the study was to evaluate the ability of motor learning based on objective, metric criteria, in terms of pedagogical process aimed at improving the accuracy of hits a golf ball to the target. A group of 77 students of physical education participated in the study. Within 8 months there were performed 11 measurement sessions. In each session, subjects performed 10 hits a golf ball to the target from a distance of 9 m. Accuracy of hits was recorded. Effect of motor learning has been demonstrated in the progress of 10 consecutive hits a golf ball to the target in each session (operational control; in the dynamics of performance improvement between sessions (current control; as well as in the total result of eight-month experiment (stage control. There were developed norms for quantitative and qualitative assessment of accuracy of hits a golf ball to the target. Developed quantitative and qualitative criteria for assessing the speed of motor learning in various conditions of the educational process creates the possibility of organization the operational, current and stage control of the level of human coordination motor abilities, as required by leading process.

  6. Development of variable-shaft-speed alternator

    Science.gov (United States)

    Rothbart, G.; Fullwood, R.

    1982-02-01

    A variable shaft speed alternator (VSSA) consists of an ordinary unmodified 1-1/2 Hp wound-rotor motor, with polyphase excitation controlled by solid state switching and a hybrid of analog and digital circuitry. This circuitry senses both shaft speed and line phase resulting in logic levels which control the current flow in each rotor coil. A first order polynomial was found using the least-squares regression method which accurately expressed the relationship among shaft speed, excitation power, and output power, VSSA torque was inferred from observations to be proportional to output power. Efficiency for converting mechanical power to electrical was inferred over a range of shaft speeds. A break-even speed below which no net power is produced was observed to be 0.375 of the synchronous speed for all output power levels. Similar behavior was observed with power fed to the power network (grid). Additional measurements involved VSSA performance at various power factors.

  7. Investigation of Flux-Linkage Profile Measurement Methods for Switched-Reluctance Motors and Permanent-Magnet Motors

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2009-01-01

    Knowledge of actual flux linkage versus current profiles plays an important role in design verification and performance prediction for switched reluctance motors (SRM's) and permanent magnet motors (PMM's). Various measurement methods have been proposed and discussed so far but each method has its...... the described AC method on an SRM and on a PM motor. For these two motors, the measured flux-linkage-current curves are compared to those measured using other methods. The comparison results show good effectiveness of the proposed AC method for both the SRM and the PM motor....

  8. Unit commitment considering alternating current power flow constraints%交流潮流约束下的机组组合求解

    Institute of Scientific and Technical Information of China (English)

    潘志远; 韩学山; 刘超男

    2012-01-01

    With the parallel development of distributed generation technology and large power grid technology, a great amount of renewable energy generation was introduced to the electrical power grid. Under this circumstance, a unit commitment model was established by considering the constraints of transmission safety using AC (alternating current) power flow. This model also involved reactive and voltage constraints, as well as safe operation limits of generators. According to the Benders decomposition, the model was decomposed into a master problem and a sub-problem. The master problem could solve the unit commitment without AC constraints, and then the sub-problem could check the AC constraints according to the result of the master problem. Benders cuts might develop from the sub problem, and the cuts would form additional associated constraints, which could connect the master problem and the sub problem. Simulation results of modified IEEE-14 buses case proved that the proposed method could effectively solve unit commitment problems with constraints of AC power flow.%针对当前大电网与分布式发电并进,可再生资源发电大量接入的电网发展格局,构建交流潮流约束下的机组组合模型,在传统考虑有功网络安全约束的基础上,引入无功电压的制约,并计及机组的安全运行极限。依据Benders分解思想,将该模型分解为主、子两个问题,主问题为单母线模型机组组合,子问题为交流潮流约束的检验,通过子问题导引的Benders割形成主、子问题之间关联的附加约束。修正的IEEE-14节点仿真结果表明,该方法能够有效解决交流潮流约束下的机组组合问题。

  9. Private Housing or Alternative Financing?

    Science.gov (United States)

    Bruno, Nick

    1999-01-01

    Explores the history of privatizing university housing and some current financing options, including use of developer and private foundations. Examples of successful alternative financing methods are highlighted. (GR)

  10. Handbook on linear motor application

    International Nuclear Information System (INIS)

    This book guides the application for Linear motor. It lists classification and speciality of Linear Motor, terms of linear-induction motor, principle of the Motor, types on one-side linear-induction motor, bilateral linear-induction motor, linear-DC Motor on basic of the motor, linear-DC Motor for moving-coil type, linear-DC motor for permanent-magnet moving type, linear-DC motor for electricity non-utility type, linear-pulse motor for variable motor, linear-pulse motor for permanent magneto type, linear-vibration actuator, linear-vibration actuator for moving-coil type, linear synchronous motor, linear electromagnetic motor, linear electromagnetic solenoid, technical organization and magnetic levitation and linear motor and sensor.

  11. 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

  12. Energy balance in motor vehicles

    Science.gov (United States)

    Dziubńiski, M.; Drozd, A.; Adamiec, M.; Siemionek, E.

    2016-09-01

    This paper present the concept of testing energy balance. The test was conducted on the test bench equipped with the alternator, battery and standard mounted current receivers. The course of measurements consisted in recording the indications of three ammeters and a tachometer. On the basis of the recorded current values, it was possible to determine: energy received from the battery, consumed by the receivers and the energy drawn from the alternator.

  13. Chronic motor tic disorder

    Science.gov (United States)

    Chronic vocal tic disorder; Tic - chronic motor tic disorder ... Chronic motor tic disorder is more common than Tourette syndrome . Chronic tics may be forms of Tourette syndrome. Tics usually start ...

  14. Fine motor control

    Science.gov (United States)

    ... figure out the child's developmental age. Children develop fine motor skills over time, by practicing and being taught. To have fine motor control, children need: Awareness and planning Coordination ...

  15. Alternating current impedance imaging of high-resistance membrane pores using a scanning electrochemical microscope. Application of membrane electrical shunts to increase measurement sensitivity and image contrast.

    Science.gov (United States)

    Ervin, Eric Nathan; White, Henry S; Baker, Lane A; Martin, Charles R

    2006-09-15

    Whether an individual pore in a porous membrane can be imaged using scanning electrochemical microscopy (SECM), operated in ac impedance mode, is determined by the magnitude of the change in the total impedance of the imaging system as the SECM tip is scanned over the pore. In instances when the SECM tip resistance is small relative to the internal pore resistance, the total impedance changes by a negligible amount, rendering the pore invisible during impedance imaging. A simple solution to this problem is to introduce a low-impedance electrical shunt (i.e., a salt bridge) across the membrane. This principle is demonstrated by imaging polycarbonate membranes (6-12-microm thickness) containing between 1 and 2000 conical-shaped pores (60-nm- and 2.5-microm-diameter openings) using an approximately 1-microm-radius Pt tip. Theory and experiments show that image contrast (the change in ac current measured as the probe is scanned over the pore) is inversely proportional to the total resistance of the membrane and can be increased by a factor of approximately 50x by introducing a low-resistance electrical shunt across the membrane. Remarkably, SECM images of membranes containing a single high-resistance (approximately 1 G Omega) pore can only be imaged by short-circuiting the membrane. Image contrast also becomes independent of membrane resistance when an electrical shunt is used, allowing for more quantitative comparisons of the features in ac impedance images of different membranes. PMID:16970331

  16. Abnormal Analysis and Processing of a Direct Current String into Alternating Current Circuit in Substation%一起变电站直流串入交流回路的异常分析与处理

    Institute of Scientific and Technical Information of China (English)

    申涛

    2016-01-01

    In the process of #2 main transformer recommision operation of certain 500kV substation, after the grounding switch blade of #2 main transformer at 220 kV side was pulled open, the direct current grounding alarm occurred; while the grounding switch blade of #2 main transformer was closed, the direct current grounding alarm disappeared. After analysis and search, the abnormal insulation between two pairs of contact in thermal relay F1 was the cause of alarm events in 3221 switch blade operation box of #2 main transformer, which has elec-tric locking relationship with the grounding switch blade at 220 kV side. The concrete fault treating procedure was expounded. This paper gave the matters need attention to prevent direct current grounding in the process of substation design, construction, operation and mainte-nance.%针对某500kV变电站2号主变复役操作过程中,当拉开2号主变220kV侧接地闸刀后,出现直流接地报警,合上该接地闸刀,直流接地告警消失的异常情况,经过分析查找,发现与该主变220 kV侧接地闸刀有联闭锁关系的2号主变2号电容器3221闸刀机构箱内的热继电器F1两副接点间内绝缘异常,导致直流串入闸刀交流控制回路。阐述了具体的故障处理过程,并给出了变电站在设计、施工、运维过程中防止直流接地的注意事项。

  17. Edinburgh Motor Assessment (EMAS)

    OpenAIRE

    Bak, Thomas

    2013-01-01

    Edinburgh Motor Assessment (EMAS) is a brief motor screening test, specifically designed for assessment of patients with dementia, aphasia and other cognitive disorders. It focuses, therefore, on those motor symptoms, which are known to occur in association with these diseases, such as extrapyramidal, amyotrophic, and cerebellar features as well as complex cognitive‐motor phenomena such as apraxia. EMAS has been developed by a team of neurologists and psychiatrists at the ...

  18. CONSOLIDATION OF MOTOR MEMORY

    OpenAIRE

    Krakauer, John W.; Shadmehr, Reza

    2005-01-01

    A question of great recent interest is whether motor memory consolidates in a manner analogous to declarative memories, with the formation of a memory that progresses over time from a fragile state, susceptible to interference by a lesion or a conflicting motor task, to a stabilized state, resistant to such interference. Here, we first review studies that examine the anatomical basis for motor consolidation: evidence implicates cerebellar circuitry for two types of associative motor learning,...

  19. Development of Ulta-Efficient Electric Motors

    Energy Technology Data Exchange (ETDEWEB)

    Shoykhet, B. (Baldor Comp.); Schiferl, R. (Baldor Comp.); Duckworth, R.; Rey, C.M.; Schwenterly, S.W.; Gouge, M.J.

    2008-05-01

    . Between the HTS field winding and the physical air gap is a series of concentric cylinders that act as vacuum insulation space walls as well as conducting paths for induced currents to flow in order to shield the HTS winding and the rotor cold space from time dependent fields. These time dependent fields may be caused by rotor hunting, during a change in motor load, or by non-fundamental component voltages and currents applied by the inverter. These motors are variable speed controlled by the inverter. Common large motor utility and industrial applications are pump and fan drives that are best suited by a variable speed motor. Inverter control of the HTS motor eliminates the need to design the rotor for line starting, which would dump a large amount of heat into the rotor that would then heavily tax the cryogenic cooling system. The field winding is fed by a brushless exciter that provides DC current to the HTS rotor winding. The stator winding is air or water cooled. Technical and commercial hurdles to industrial HTS motor product introduction and customer acceptance include (1) the high cost of HTS wire and the cryogenic cooling system components, (2) customer concerns about reliability of HTS motors, and (3) the ability to attain the loss reduction potential of large HTS motors. Reliance Electric has demonstrated a number of HTS based electric motors up to a 1000 hp, variable speed synchronous motor with an HTS field winding in the year 2000. In 2001 this motor was tested to 1600 hp with a sinusoidal (constant frequency) supply. Figure 1-2 shows the HTS motor on the dynamometer test stand in the Reliance Electric test lab. The extensive test program of the 1000 hp motor successfully demonstrated the technical feasibility of large HTS motors and the basic technologies involved, however the test results did indicate the need for design refinements. In addition, test results served to identify other more fundamental critical technology issues, and revealed the need to

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

    Directory of Open Access Journals (Sweden)

    Rukmini

    2015-03-01

    Full Text Available 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 to modelling. Simulink (one of Matlab toolboxes was used to model the forward and reverse of DC hoist motor. When lifting the container (forward motoring, the current required depends on the applied load torque. But when lowering the containers (reverse motoring, the voltage generated by the engine polarity reverse is determined by the downward movement of containers (mass and height. Reverse the polarity, and let the motor functions as a generator, produces a current and then the potential energy was calculated. Conclusions were drawn at the end of the paper.

  1. Motor Neurons that Multitask

    OpenAIRE

    Goulding, Martyn

    2012-01-01

    Animals use a form of sensory feedback termed proprioception to monitor their body position and modify the motor programs that control movement. In this issue of Neuron, Wen et al. (2012) provide evidence that a subset of motor neurons function as proprioceptors in C. elegans, where B-type motor neurons sense body curvature to control the bending movements that drive forward locomotion.

  2. Quantum motor and future

    CERN Document Server

    Fateev, Evgeny G

    2013-01-01

    In a popular language, the possibilities of the Casimir expulsion effect are presented, which can be the basis of quantum motors. Such motors can be in the form of a special multilayer thin film with periodic and complex nanosized structures. Quantum motors of the type of the Casimir platforms can be the base of transportation, energy and many other systems in the future.

  3. Calculation of Stator Current Fluctuation and Selection of Flywheel Torque of the Synchronous Motor to Drive the Compressor%驱动压缩机用同步电动机的定子电流波动计算与飞轮力矩选择

    Institute of Scientific and Technical Information of China (English)

    陈兴卫

    2014-01-01

    讨论了驱动往复式压缩机用同步电动机定子电流波动的计算和飞轮力矩的选择。介绍了合理选择同步电动机的飞轮力矩和控制定子电流波动计算方法,为同步电动机设计提供参考。%The calculation of stator current fluctuation and selection of flywheel torque of the synchronous motor to drive the compressor were discussed. The way to select the flywheel torque reasonably and calculation to control the stator current fluctuation were proposed, thus to provide the reference for the synchronous motor design.

  4. 基于电流波形检测法的开关磁阻电动机无位置传感器控制%Sensorless Control of Switched Reluctance Motor Based on Current Waveform Detection Method

    Institute of Scientific and Technical Information of China (English)

    李珍国; 王红斌; 王江浩; 高雪飞; 张纯江

    2016-01-01

    开关磁阻电动机( SRM)在采用电压PWM控制方式时,通常在定、转子齿极开始重叠位置处出现峰值电流。传统电流梯度法利用该峰值电流的前后电流微分值符号变反的特征,通过微分和过零检测电路得到转子位置,但存在检测电路参数设计繁琐,低速运行时不易获取正确的转子位置以及容错能力较差等缺点。为此,提出了一种基于电流波形检测的转子位置估算方法。该方法通过比较前后时刻电流大小,在该相关断时刻确定该相电流峰值及其对应的时间,并与前一相峰值电流对应时间共同计算确定后一相的关断时间。随后通过给定开通角,计算出开通角对应脉冲数,再通过比较当前计数值与该开通角对应的脉冲数,确定当前相或后一相的开通时间。该方法不仅保留了不依赖SRM参数的优点,而且无需微分、过零检测等外围电路,在低速运行时也能够得到正确的转子位置且具有较强的容错能力。通过基于该方法搭建的SRM无位置传感器控制系统的DSP驱动实验,证明了所提方法的可行性和有效性。%In case of switched reluctance motor( SRM)using voltage PWM control mode,the peak current usually appears at the initial overlapping position between the stator and the rotor poles. In the conventional current gradient method,the rotor position can be estimated through the differential and zero crossing detection circuit by using the characteristics of the sign inversion of the current differential value before and after the peak current. However this method has such disadvantages as tedious parameters design for differential and zero crossing detection circuit,difficulty in obtaining the correct rotor position under the low-speed region,and poor fault tolerance ability. For these reasons,a current waveform detection based rotor position estimation method is proposed in this paper. This method

  5. Miniaturization of planar horn motors

    Science.gov (United States)

    Sherrit, Stewart; Ostlund, Patrick N.; Chang, Zensheu; Bao, Xiaoqi; Bar-Cohen, Yoseph; Widholm, Scott E.; Badescu, Mircea

    2012-04-01

    There is a great need for compact, efficient motors for driving various mechanisms including robots or mobility platforms. A study is currently underway to develop a new type of piezoelectric actuators with significantly more strength, low mass, small footprint, and efficiency. The actuators/motors utilize piezoelectric actuated horns which have a very high power density and high electromechanical conversion efficiency. The horns are fabricated using our recently developed novel pre-stress flexures that make them thermally stable and increases their coupling efficiency. The monolithic design and integrated flexures that pre-stresses the piezoelectric stack eliminates the use of a stress bolt. This design allows embedding solid-state motors and actuators in any structure so that the only macroscopically moving parts are the rotor or the linear translator. The developed actuator uses a stack/horn actuation and has a Barth motor configuration, which potentially generates very large torque and speeds that do not require gearing. Finite element modeling and design tools were investigated to determine the requirements and operation parameters and the results were used to design and fabricate a motor. This new design offers a highly promising actuation mechanism that can potentially be miniaturized and integrated into systems and structures. It can be configured in many shapes to operate as multi-degrees of freedom and multi-dimensional motors/actuators including unidirectional, bidirectional, 2D and 3D. In this manuscript, we are reporting the experimental measurements from a bench top design and the results from the efforts to miniaturize the design using 2×2×2 mm piezoelectric stacks integrated into thin plates that are of the order of 3 × 3 × 0.2 cm.

  6. Miniaturization of Planar Horn Motors

    Science.gov (United States)

    Sherrit, Stewart; Ostlund, Patrick N.; Chang, Zensheu; Bao, Xiaoqi; Bar-Cohen, Yoseph; Widholm, Scott E.; Badescu, Mircea

    2012-01-01

    There is a great need for compact, efficient motors for driving various mechanisms including robots or mobility platforms. A study is currently underway to develop a new type of piezoelectric actuators with significantly more strength, low mass, small footprint, and efficiency. The actuators/motors utilize piezoelectric actuated horns which have a very high power density and high electromechanical conversion efficiency. The horns are fabricated using our recently developed novel pre-stress flexures that make them thermally stable and increases their coupling efficiency. The monolithic design and integrated flexures that pre-stresses the piezoelectric stack eliminates the use of stress bolt. This design allows embedding solid-state motors and actuators in any structure so that the only macroscopically moving parts are the rotor or the linear translator. The developed actuator uses a stack/horn actuation and has a Barth motor configuration, which potentially generates very large torque and speeds that do not require gearing. Finite element modeling and design tools were investigated to determine the requirements and operation parameters and the results were used to design and fabricate a motor. This new design offers a highly promising actuation mechanism that can potentially be miniaturized and integrated into systems and structures. It can be configured in many shapes to operate as multi-degrees of freedom and multi-dimensional motors/actuators including unidirectional, bidirectional, 2D and 3D. In this manuscript, we are reporting the experimental measurements from a bench top design and the results from the efforts to miniaturize the design using 2x2x2 mm piezoelectric stacks integrated into thin plates that are of the order of3 x 3x 0.2 cm.

  7. Development of a Human Motor Model for the Evaluation of an Integrated Alerting and Notification Flight Deck System

    Science.gov (United States)

    Daiker, Ron; Schnell, Thomas

    2010-01-01

    A human motor model was developed on the basis of performance data that was collected in a flight simulator. The motor model is under consideration as one component of a virtual pilot model for the evaluation of NextGen crew alerting and notification systems in flight decks. This model may be used in a digital Monte Carlo simulation to compare flight deck layout design alternatives. The virtual pilot model is being developed as part of a NASA project to evaluate multiple crews alerting and notification flight deck configurations. Model parameters were derived from empirical distributions of pilot data collected in a flight simulator experiment. The goal of this model is to simulate pilot motor performance in the approach-to-landing task. The unique challenges associated with modeling the complex dynamics of humans interacting with the cockpit environment are discussed, along with the current state and future direction of the model.

  8. Fuzzy Logic Controlled Solar Module for Driving Three- Phase Induction Motor

    Science.gov (United States)

    Afiqah Zainal, Nurul; Sooi Tat, Chan; Ajisman

    2016-02-01

    Renewable energy produced by solar module gives advantages for generated three- phase induction motor in remote area. But, solar module's ou tput is uncertain and complex. Fuzzy logic controller is one of controllers that can handle non-linear system and maximum power of solar module. Fuzzy logic controller used for Maximum Power Point Tracking (MPPT) technique to control Pulse-Width Modulation (PWM) for switching power electronics circuit. DC-DC boost converter used to boost up photovoltaic voltage to desired output and supply voltage source inverter which controlled by three-phase PWM generated by microcontroller. IGBT switched Voltage source inverter (VSI) produced alternating current (AC) voltage from direct current (DC) source to control speed of three-phase induction motor from boost converter output. Results showed that, the output power of solar module is optimized and controlled by using fuzzy logic controller. Besides that, the three-phase induction motor can be drive and control using VSI switching by the PWM signal generated by the fuzzy logic controller. This concluded that the non-linear system can be controlled and used in driving three-phase induction motor.

  9. Development of an induction motor abnormality monitoring system(IMAMS) using power line signal analysis

    International Nuclear Information System (INIS)

    An induction motor abnormality monitoring system using power line signal analysis is developed in this work. Various studies have focused their attention on the detection of particular harmonic frequencies produced from each defect mode of motors. However, these harmonic frequencies are valuable only when the motor has a continuous slip frequency and operate in constant torque/load condition. The basic concept of the system developed in this work is to detect the characteristic harmonic frequencies occurred when the motor is in abnormal state and to compare it with a predetermined setpoint. Based on these analyses, the place and degree of defect can be easily identified. The experimental results under test bench simulation are also introduced. To find out an alternative way to obtain a threshold level independent of slip/torque, with the rotating field theory, the ratio between harmonic current and total current was calculated with the simplified circuit that is equivalent to two abnormal cases, such as the spatial rotor resistance variation and the symmetrical components changes with field. Also, the threshold level calculation was done with performed the rotating field theory. The results show that they are in good agreement with a experimental results. Further studies are undertaken to extend this work to the on-line monitoring and diagnostic system with a likelihood ratio test method for field application

  10. Q-Sync Motors in Commercial Refrigeration. Preliminary Test Results and Projected Benefits

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Brian A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Becker, Bryan R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-09-01

    This report provides background information on various fractional-horsepower electric motor technologies, summarizes initial data from a DOE-sponsored Q-Sync motor demonstration project, and extrapolates that data to project the potential economic and environmental benefits resulting from upgrading the current installed base of 9–12 W evaporator fan motors to Q-Sync motors.

  11. Motor imagery training in hemiplegic cerebral palsy: a potentially useful therapeutic tool for rehabilitation

    NARCIS (Netherlands)

    Steenbergen, B.; Craje, Céline; Nilsen, D.M.; Gordon, A.M.

    2009-01-01

    Converging evidence indicates that motor deficits in cerebral palsy (CP) are related not only to problems with execution, but also to impaired motor planning. Current rehabilitation mainly focuses on alleviating compromised motor execution. Motor imagery is a promising method of training the more 'c

  12. Solid propellant motor

    Science.gov (United States)

    Shafer, J. I.; Marsh, H. E., Jr. (Inventor)

    1978-01-01

    A case bonded end burning solid propellant rocket motor is described. A propellant with sufficiently low modulus to avoid chamber buckling on cooling from cure and sufficiently high elongation to sustain the stresses induced without cracking is used. The propellant is zone cured within the motor case at high pressures equal to or approaching the pressure at which the motor will operate during combustion. A solid propellant motor with a burning time long enough that its spacecraft would be limited to a maximum acceleration of less than 1 g is provided by one version of the case bonded end burning solid propellant motor of the invention.

  13. Motor/generator

    Science.gov (United States)

    Hickam, Christopher Dale

    2008-05-13

    A motor/generator is provided for connecting between a transmission input shaft and an output shaft of a prime mover. The motor/generator may include a motor/generator housing, a stator mounted to the motor/generator housing, a rotor mounted at least partially within the motor/generator housing and rotatable about a rotor rotation axis, and a transmission-shaft coupler drivingly coupled to the rotor. The transmission-shaft coupler may include a clamp, which may include a base attached to the rotor and a plurality of adjustable jaws.

  14. Induction motor control design

    CERN Document Server

    Marino, Riccardo; Verrelli, Cristiano M

    2010-01-01

    ""Nonlinear and Adaptive Control Design for Induction Motors"" is a unified exposition of the most important steps and concerns in the design of estimation and control algorithms for induction motors. A single notation and modern nonlinear control terminology is used to make the book accessible to readers who are not experts in electric motors at the same time as giving a more theoretical control viewpoint to those who are. In order to increase readability, the book concentrates on the induction motor, eschewing the much more complex and less-well-understood control of asynchronous motors. The

  15. 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.

  16. Validating the Rett Syndrome Gross Motor Scale.

    Science.gov (United States)

    Downs, Jenny; Stahlhut, Michelle; Wong, Kingsley; Syhler, Birgit; Bisgaard, Anne-Marie; Jacoby, Peter; Leonard, Helen

    2016-01-01

    Rett syndrome is a pervasive neurodevelopmental disorder associated with a pathogenic mutation on the MECP2 gene. Impaired movement is a fundamental component and the Rett Syndrome Gross Motor Scale was developed to measure gross motor abilities in this population. The current study investigated the validity and reliability of the Rett Syndrome Gross Motor Scale. Video data showing gross motor abilities supplemented with parent report data was collected for 255 girls and women registered with the Australian Rett Syndrome Database, and the factor structure and relationships between motor scores, age and genotype were investigated. Clinical assessment scores for 38 girls and women with Rett syndrome who attended the Danish Center for Rett Syndrome were used to assess consistency of measurement. Principal components analysis enabled the calculation of three factor scores: Sitting, Standing and Walking, and Challenge. Motor scores were poorer with increasing age and those with the p.Arg133Cys, p.Arg294* or p.Arg306Cys mutation achieved higher scores than those with a large deletion. The repeatability of clinical assessment was excellent (intraclass correlation coefficient for total score 0.99, 95% CI 0.93-0.98). The standard error of measurement for the total score was 2 points and we would be 95% confident that a change 4 points in the 45-point scale would be greater than within-subject measurement error. The Rett Syndrome Gross Motor Scale could be an appropriate measure of gross motor skills in clinical practice and clinical trials.

  17. Energy-efficient steels for motor laminations

    Science.gov (United States)

    Werner, F. E.; Jaffee, R. I.

    1992-03-01

    Motors use over 60% of all electricity generated, and their losses exceed 200 × 109 kW.hr/year. A significant part of this loss results from eddy currents and hysteretic processes in the motor laminations. These so- called core losses cost motor users about 3 × 109/year. The metallurgy and economics of using various steels are considered, with emphasis on 5- to 125- hp polyphase induction motors. A lower core loss steel, even though it is more expensive, is economically justified most of the time when the operating costs of motors are considered. Impurities must be minimized, and steels can now be made with the principal impurities being less than 30 ppm. Further reduction of core losses depends on using the best steel processing equipment available, production of a consistently low carbon content so that decarburizing during the final anneal can be eliminated, developing a better understanding of the relation between material properties and performance in motors, and an increased willingness by the motor users to pay more for better motors that are cheaper to own in the long run.

  18. DSP-based electric power assisted steering using BLDC motor

    Indian Academy of Sciences (India)

    R Murugan; S Nandakumar; M S Mohiyadeen

    2008-10-01

    This paper introduces a design and implementation of electrically assisted power steering (EAS) using BLDC motor for a vehicle. The control architecture consists of two layers of control, namely the vehicle speed associated control and the torque assist control. In the higher level of control architecture, the vehicle speed controller works as an assistance level controller for the steering effort. In the lower level, the torque controller gives the effort level control. This has been realized by torque sensor and vehicle sensor interfaced in the DSP. For implementing in the system, a DSP-based BLDC motor controller with three-phase inverter module is specially designed using Hall-effect sensor feedback and a single dc-link current sensor. This work is implemented in a Light Commercial Vehicle having a recirculating ball type gear. This is for the first time (EAS) being implemented for this type of vehicle any where in the world. Generally, EAS having clutch to disconnect the motor in high speed or abnormal conditions from the gear box. In this implementation the motor is directly coupled to gearbox without clutch and all abnormalities are handled by the processor. This is implemented without modifying the vehicle supply system like changing the existing alternator or rating of the battery and using the existing sensors. The design is such a way that the feel of the driver assistance can be varied easily at any time. The performance of the control system is experimentally verified and it is tested in one of the Light Commercial Vehicle (LCV).

  19. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  20. Piezoelectric Motors, an Overview

    Directory of Open Access Journals (Sweden)

    Karl Spanner

    2016-02-01

    Full Text Available Piezoelectric motors are used in many industrial and commercial applications. Various piezoelectric motors are available in the market. All of the piezoelectric motors use the inverse piezoelectric effect, where microscopically small oscillatory motions are converted into continuous or stepping rotary or linear motions. Methods of obtaining long moving distance have various drive and functional principles that make these motors categorized into three groups: resonance-drive (piezoelectric ultrasonic motors, inertia-drive, and piezo-walk-drive. In this review, a comprehensive summary of piezoelectric motors, with their classification from initial idea to recent progress, is presented. This review also includes some of the industrial and commercial applications of piezoelectric motors that are presently available in the market as actuators.

  1. Neuroplasticity & Motor Learning

    DEFF Research Database (Denmark)

    Jensen, Jesper Lundbye

    is a measure of our ability to form and store a motor memory of the task. However, the initial memory of the task is labile and may be subject to interference. During and following motor learning plastic changes occur within the central nervous system. On one hand these changes are driven by motor practice......, on the other hand the changes underlie the formation of motor memory and the retention of improved motor performance. During motor learning changes may occur at many different levels within the central nervous system dependent on the type of task and training. Here, we demonstrate different studies from our......Practice of a new motor task is usually associated with an improvement in performance. Indeed, if we stop practicing and return the next day to the same task, we find that our performance has been maintained and may even be better than it was at the start of the first day. This improvement...

  2. Automobiles and global warming: Alternative fuels and other options for carbon dioxide emissions reduction

    International Nuclear Information System (INIS)

    Automobiles are a source of considerable pollution at the global level, including a significant fraction of the total greenhouse gas emissions. Alternative fuels have received some attention as potential options to curtail the carbon dioxide emissions from motor vehicles. This article discusses the feasibility and desirability (from a technical as well as a broader environmental perspective) of the large-scale production and use of alternative fuels as a strategy to mitigate automotive carbon dioxide emissions. Other options such as improving vehicle efficiency and switching to more efficient modes of passenger transportation are also discussed. These latter options offer an effective and immediate way to tackle the greenhouse and other pollutant emission from automobiles, especially as the limitations of currently available alternative fuels and the technological and other constraints for potential future alternatives are revealed

  3. Energy-efficient electric motors study

    Science.gov (United States)

    1981-03-01

    A survey conducted of purchasers of integral horsepower polyphase motors measured current knowledge of and awareness of energy efficient motors, decision making criteria, information sources, purchase and usage patterns, and related factors. The data obtained were used for the electric motor market penetration analysis. Additionally, a telephone survey was made. The study also provides analyses of distribution channels, commercialization constraints, and the impacts of government programs and rising energy prices. Study findings, conclusions, and recommendations are presented. Sample questionnaires and copies of letters to respondents are presented in appendices as well as descriptions of the methods used.

  4. Analytical and experimental study of high phase order induction motors

    Science.gov (United States)

    Klingshirn, Eugene A.

    1989-08-01

    Induction motors having more than three phases were investigated to determine their suitability for electric vehicle applications. The objective was to have a motor with a current rating lower than that of a three-phase motor. The name chosen for these is high phase order (HPO) motors. Motors having six phases and nine phases were given the most attention. It was found that HPO motors are quite suitable for electric vehicles, and for many other applications as well. They have characteristics which are as good as or better than three-phase motors for practically all applications where polyphase induction motors are appropriate. Some of the analysis methods are presented, and several of the equivalent circuits which facilitate the determination of harmonic currents and losses, or currents with unbalanced sources, are included. The sometimes large stator currents due to harmonics in the source voltages are pointed out. Filters which can limit these currents were developed. An analysis and description of these filters is included. Experimental results which confirm and illustrate much of the theory are also included. These include locked rotor test results and full-load performance with an open phase. Also shown are oscillograms which display the reduction in harmonic currents when a filter is used with the experimental motor supplied by a non-sinusoidal source.

  5. Alternative Treatments

    Science.gov (United States)

    ... Find your chapter: search by state Home > Alzheimer's Disease > Treatments > Alternative Treatments Overview What Is Dementia? What Is Alzheimer's? Younger/Early Onset Facts and Figures Know the 10 Signs Stages Inside the Brain: ...

  6. Traffic of cytoskeletal motors with disordered attachment rates

    Science.gov (United States)

    Grzeschik, H.; Harris, R. J.; Santen, L.

    2010-03-01

    Motivated by experimental results on the interplay between molecular motors and tau proteins, we extend lattice-based models of intracellular transport to include a second species of particle which locally influences the motor-filament attachment rate. We consider various exactly solvable limits of a stochastic multiparticle model before focusing on the low-motor-density regime. Here, an approximate treatment based on the random-walk behavior of single motors gives good quantitative agreement with simulation results for the tau dependence of the motor current. Finally, we discuss the possible physiological implications of our results.

  7. Robust Speed and Parameter Estimation in Induction Motors

    DEFF Research Database (Denmark)

    Børsting, H.; Vadstrup, P.

    1995-01-01

    This paper presents a Model Reference Adaptive System (MRAS) for the estimation of the induction motor speed, based on measured terminal voltages and currents.......This paper presents a Model Reference Adaptive System (MRAS) for the estimation of the induction motor speed, based on measured terminal voltages and currents....

  8. Incorporating future change into current conservation planning: Evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios

    Science.gov (United States)

    Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.

    2015-11-02

    In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

  9. Incorporating future change into current conservation planning: Evaluating tidal saline wetland migration along the U.S. Gulf of Mexico coast under alternative sea-level rise and urbanization scenarios

    Science.gov (United States)

    Enwright, Nicholas M.; Griffith, Kereen T.; Osland, Michael J.

    2015-01-01

    In this study, the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service, quantified the potential for landward migration of tidal saline wetlands along the U.S. Gulf of Mexico coast under alternative future sea-level rise and urbanization scenarios. Our analyses focused exclusively on tidal saline wetlands (that is, mangrove forests, salt marshes, and salt flats), and we combined these diverse tidal saline wetland ecosystems into a single grouping, “tidal saline wetland.” Collectively, our approach and findings can provide useful information for scientists and environmental planners working to develop future-focused adaptation strategies for conserving coastal landscapes and the ecosystem goods and services provided by tidal saline wetlands. The primary product of this work is a public dataset that identifies locations where landward migration of tidal saline wetlands is expected to occur under alternative future sea-level rise and urbanization scenarios. In addition to identifying areas where landward migration of tidal saline wetlands is possible because of the absence of barriers, these data also identify locations where landward migration of these wetlands could be prevented by barriers associated with current urbanization, future urbanization, and levees.

  10. Alternating Current Heating Technique of Hollow Rod

    Institute of Scientific and Technical Information of China (English)

    Na Weisheng; Shi Tonghao

    1995-01-01

    @@ In recent years, wellbore heat tracing technique is widely used in development of high viscosity and high pour point crude oil. Theory and experiences show that wellbore heat tracing has obvious effect on increasing liquid yield of oil wells.

  11. Electrical energy saving in motors and frequency variators; Ahorro de energia electrica en motores y variadores de frecuencia

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Neri, Roger [Comision Federal de Electricidad (CFE) (Mexico)

    2005-07-01

    The necessity of saving energy is urgent and undeniable. We must already begin with the rational use of energy. Which is obtaining the maximum benefit of the consumed energy and of the necessary facilities for its generation, transmission and use. Guaranteeing at the same time an operation free of interferences or interruptions for the users. The electricity in alternating current does not allow its storage, reason why it is necessary to generate and distribute it at the precise moment when it is required. This forces to determine the proportions of the generation facilities, to be able to feed the periods of maximum demand called {sup p}eaks{sup .} It is this very point where the problem of the inappropriate use of the electrical energy starts. The energy waste is self-evident during the periods of low demand because of the low efficiency of the sub-utilized facilities. Electrical motors of the induction type use approximately more than 60% of the energy in the industry. If we use high efficiency motors instead of standard motors, a better advantage of the energy demanded from Comision Federal de Electricidad (CFE) is obtained. [Spanish] Es impostergable e innegable la necesidad de ahorrar energia. Tenemos que empezar ya con el uso racional de la energia: Obtener el maximo beneficio de la energia consumida y de las instalaciones necesarias para su generacion, transmision y utilizacion. Garantizando a los usuarios un funcionamiento sin interferencias o interrupciones. La electricidad en corriente alterna no permite su almacenamiento, por lo que es necesario generarla y distribuirla en el momento preciso en que es requerida. Esto obliga a dimensionar las instalaciones de generacion, para poder alimentar los periodos de maxima demanda llamados pico. Desde esta parte inicia el problema de la mala utilizacion de la energia electrica. Ya que en los periodos de baja demanda, las instalaciones se encuentran subutilizadas y si su eficiencia es muy baja, el desperdicio de

  12. Enhanced Cancer Cell (HeLa Killing Efficacy of Mixed Αlpha and Gamma Iron Oxide Superparamagnetic Nanoparticles under Combined AC (Alternating Current Magnetic-Field and Photoexcitation

    Directory of Open Access Journals (Sweden)

    Md. Shariful Islam, Yoshihumi Kusumoto, Md. Abdulla Al-Mamun and Yuji Horie

    2011-12-01

    Full Text Available We synthesized mixed α and γ-Fe2O3 nanoparticles and investigated their toxic effects against HeLa cells under induced AC (alternating current magnetic-fields and photoexcited conditions at room temperature. The findings revealed that the cell-killing percentage was increased with increasing dose for all types of treatments. Finally, 99% cancer cells were destructed at 1.2 mL dose when exposed to combined AC magnetic-field and photoexcited conditions (T3 whereas 89 and 83 % of HeLa cells were killed under only AC magnetic-field induced (T1 or only photoexcited (T2 condition at the same dose.ABSTRAK: Campuran α dan zarah γ-Fe2O3 bersaiz nano disintesiskan dan kesan toksidnya terhadap sel HeLa dikaji dibawah aruhan medan magnet arus ulang-alik (alternating current (AC dan keadaan photoexcited (proses ransangan atom atau molekul suatu bahan dengan penyerapan tenaga sinaran pada suhu bilik. Penemuan mendedahkan bahawa peratusan sel yang musnah bertambah dengan pertambahan dos untuk semua jenis rawatan. Akhirnya, 99% sel kanser dimusnahkan pada kadar dos 1.2mL setelah didedahkan terhadap kombinasi medan magnet AC dan keadaan photoexcited (T3 dimana 89% dan 83% sel HeLa dimusnahkan dengan hanya di bawah aruhan medan magnet AC (T1 atau hanya pada keadaan photoexcited (T2 pada kadar dos yang sama.KEY WORDS : Cancer, Hyperthermia, Iron oxide nanoparticles, Heat dissipation,    Cytotoxicity, HeLa cell.

  13. Motor degradation prediction methods

    International Nuclear Information System (INIS)

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures

  14. The distal hereditary motor neuropathies.

    Science.gov (United States)

    Rossor, Alexander M; Kalmar, Bernadett; Greensmith, Linda; Reilly, Mary M

    2012-01-01

    The distal hereditary motor neuropathies (dHMN) comprise a heterogeneous group of diseases that share the common feature of a length-dependent predominantly motor neuropathy. Many forms of dHMN have minor sensory abnormalities and/or a significant upper-motor-neuron component, and there is often an overlap with the axonal forms of Charcot-Marie-Tooth disease (CMT2) and with juvenile forms of amyotrophic lateral sclerosis and hereditary spastic paraplegia. Eleven causative genes and four loci have been identified with autosomal dominant, recessive and X-linked patterns of inheritance. Despite advances in the identification of novel gene mutations, 80% of patients with dHMN have a mutation in an as-yet undiscovered gene. The causative genes have implicated proteins with diverse functions such as protein misfolding (HSPB1, HSPB8, BSCL2), RNA metabolism (IGHMBP2, SETX, GARS), axonal transport (HSPB1, DYNC1H1, DCTN1) and cation-channel dysfunction (ATP7A and TRPV4) in motor-nerve disease. This review will summarise the clinical features of the different subtypes of dHMN to help focus genetic testing for the practising clinician. It will also review the neuroscience that underpins our current understanding of how these mutations lead to a motor-specific neuropathy and highlight potential therapeutic strategies. An understanding of the functional consequences of gene mutations will become increasingly important with the advent of next-generation sequencing and the need to determine the pathogenicity of large amounts of individual genetic data.

  15. Motor Axon Pathfinding

    OpenAIRE

    Bonanomi, Dario; Pfaff, Samuel L

    2010-01-01

    Motor neurons are functionally related, but represent a diverse collection of cells that show strict preferences for specific axon pathways during embryonic development. In this article, we describe the ligands and receptors that guide motor axons as they extend toward their peripheral muscle targets. Motor neurons share similar guidance molecules with many other neuronal types, thus one challenge in the field of axon guidance has been to understand how the vast complexity of brain connection...

  16. Subcontract Report: Final Report on Assessment of Motor Technologies for Traction Drives of Hybrid and Electric Vehicles (Subcontract #4000080341)

    Energy Technology Data Exchange (ETDEWEB)

    Fezzler, Raymond [BIZTEK Consulting, Inc.

    2011-03-01

    Currently, interior permanent magnet (IPM) motors with rare-earth (RE) magnets are almost universally used for hybrid and electric vehicles (EVs) because of their superior properties, particularly power density. However, there is now a distinct possibility of limited supply or very high cost of RE magnets that could make IPM motors unavailable or too expensive. Because development of electric motors is a critical part of the U.S. Department of Energy (DOE) Advanced Power Electronics and Motors activity, DOE needs to determine which options should be investigated and what barriers should be addressed. Therefore, in order to provide a basis for deciding which research topics should be pursued, an assessment of various motor technologies was conducted to determine which, if any, is potentially capable of meeting FreedomCAR 2015 and 2020 targets. Highest priority was given to IPM, surface mounted permanent magnet (SPM), induction, and switched reluctance (SR) motors. Also of interest, but with lesser emphasis, were wheel motors, multiple-rotor motors, motors with external excitation, and several others that emerged from the assessment. Cost and power density (from a design perspective, the power density criterion translates to torque density) are emerging as the two most important properties of motors for traction drives in hybrid and EVs, although efficiency and specific power also are very important. The primary approach for this assessment involved interviews with original equipment manufacturers (OEMs), their suppliers, and other technical experts. For each technology, the following issues were discussed: (1) The current state-of-the-art performance and cost; (2) Recent trends in the technology; (3) Inherent characteristics of the motor - which ones limit the ability of the technology to meet the targets and which ones aid in meeting the target; (4) What research and development (R&D) would be needed to meet the targets; and (5) The potential for the technology to

  17. System and method to determine electric motor efficiency using an equivalent circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Habetler, Thomas G.

    2015-10-27

    A system and method for determining electric motor efficiency includes a monitoring system having a processor programmed to determine efficiency of an electric motor under load while the electric motor is online. The determination of motor efficiency is independent of a rotor speed measurement. Further, the efficiency is based on a determination of stator winding resistance, an input voltage, and an input current. The determination of the stator winding resistance occurs while the electric motor under load is online.

  18. Control motor brushless sensorless

    OpenAIRE

    Solchaga Pérez de Lazárraga, Gonzalo

    2015-01-01

    El proyecto consiste en la creación de un circuito capaz de controlar la velocidad de un motor brushless sensorless. Este tipo de motores eléctricos tienen como característica que no tienen escobillas para cambiar la polaridad del bobinado de su interior y tampoco precisan de un sensor que indique que ha realizado una vuelta. Los motores brushless que son controlados por este tipo de circuitos son específicos para aeronaves no tripuladas y requieren un diseño diferente a un motor brushless pe...

  19. Cosmic alternatives?

    Science.gov (United States)

    Gregory, Ruth

    2009-04-01

    "Cosmologists are often in error but never in doubt." This pithy characterization by the Soviet physicist Lev Landau sums up the raison d'être of Facts and Speculations in Cosmology. Authors Jayant Narlikar and Geoffrey Burbidge are proponents of a "steady state" theory of cosmology, and they argue that the cosmological community has become fixated on a "Big Bang" dogma, suppressing alternative viewpoints. This book very much does what it says on the tin: it sets out what is known in cosmology, and puts forward the authors' point of view on an alternative to the Big Bang.

  20. Impairments of social motor coordination in schizophrenia.

    Directory of Open Access Journals (Sweden)

    Manuel Varlet

    Full Text Available It has been demonstrated that motor coordination of interacting people plays a crucial role in the success of social exchanges. Abnormal movements have been reported during interpersonal interactions of patients suffering from schizophrenia and a motor coordination breakdown could explain this social interaction deficit, which is one of the main and earliest features of the illness. Using the dynamical systems framework, the goal of the current study was (i to investigate whether social motor coordination is impaired in schizophrenia and (ii to determine the underlying perceptual or cognitive processes that may be affected. We examined intentional and unintentional social motor coordination in participants oscillating hand-held pendulums from the wrist. The control group consisted of twenty healthy participant pairs while the experimental group consisted of twenty participant pairs that included one participant suffering from schizophrenia. The results showed that unintentional social motor coordination was preserved while intentional social motor coordination was impaired. In intentional coordination, the schizophrenia group displayed coordination patterns that had lower stability and in which the patient never led the coordination. A coupled oscillator model suggests that the schizophrenia group coordination pattern was due to a decrease in the amount of available information together with a delay in information transmission. Our study thus identified relational motor signatures of schizophrenia and opens new perspectives for detecting the illness and improving social interactions of patients.