Software and hardware complex for research and management of the separation process

NASA Astrophysics Data System (ADS)

Borisov, A. P.

2018-01-01

The article is devoted to the development of a program for studying the operation of an asynchronous electric drive using vector-algorithmic switching of windings, as well as the development of a hardware-software complex for controlling parameters and controlling the speed of rotation of an asynchronous electric drive for investigating the operation of a cyclone. To study the operation of an asynchronous electric drive, a method was used in which the average value of flux linkage is found and a method for vector-algorithmic calculation of the power and electromagnetic moment of an asynchronous electric drive feeding from a single-phase network is developed, with vector-algorithmic commutation, and software for calculating parameters. The software part of the complex allows to regulate the speed of rotation of the motor by vector-algorithmic switching of transistors or, using pulse-width modulation (PWM), set any engine speed. Also sensors are connected to the hardware-software complex at the inlet and outlet of the cyclone. The developed cyclone with an inserted complex allows to receive high efficiency of product separation at various entrance speeds. At an inlet air speed of 18 m / s, the cyclone’s maximum efficiency is achieved. For this, it is necessary to provide the rotational speed of an asynchronous electric drive with a frequency of 45 Hz.

Temporal prediction abilities are mediated by motor effector and rhythmic expertise.

PubMed

Manning, Fiona C; Harris, Jennifer; Schutz, Michael

2017-03-01

Motor synchronization is a critical part of musical performance and listening. Recently, motor control research has described how movements that contain more available degrees of freedom are more accurately timed. Previously, we demonstrated that stick tapping improves perception in a timing detection task, where percussionists greatly outperformed non-percussionists only when tapping along. Since most synchronization studies implement finger tapping to examine simple motor synchronization, here we completed a similar task where percussionists and non-percussionists synchronized using finger tapping; movement with fewer degrees of freedom than stick tapping. Percussionists and non-percussionists listened to an isochronous beat sequence and identified the timing of a probe tone. On half of the trials, they tapped along with their index finger, and on the other half of the trials, they listened without moving prior to making timing judgments. We found that both groups benefited from tapping overall. Interestingly, percussionists performed only marginally better than did non-percussionists when finger tapping and no different when listening alone, differing from past studies reporting highly superior timing abilities in percussionists. Additionally, we found that percussionist finger tapping was less variable and less asynchronous than was non-percussionist tapping. Moreover, in both groups finger tapping was more variable and more asynchronous than stick tapping in our previous study. This study demonstrates that the motor effector implemented in tapping studies affects not only synchronization abilities, but also subsequent prediction abilities. We discuss these findings in light of effector-specific training and degrees of freedom in motor timing, both of which impact timing abilities to different extents.

The control system of synchronous movement of the gantry crane supports

NASA Astrophysics Data System (ADS)

Odnokopylov, I. G.; Gneushev, V. V.; Galtseva, O. V.; Natalinova, N. M.; Li, J.; Serebryakov, D. I.

2017-01-01

The paper presents study findings on synchronization of the gantry crane support movement. Asynchrony moving speed bearings may lead to an emergency mode at the natural rate of deformed metal structure alignment. The use of separate control of asynchronous motors with the vector control method allows synchronizing the movement speed of crane supports and achieving a balance between the motors. Simulation results of various control systems are described. Recommendations regarding the system further application are given.

On the theory of 3-phase squirrel-cage induction motors including space harmonics and mutual slotting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papp, G.C.

1991-03-01

In this paper general equations for the asynchronous squirrel-cage motor which contain the influence of space harmonics and the mutual slotting are derived by using among others the power-invariant symmetrical component transformation and a time-dependent transformation with which, under certain circumstances, the rotor-position angle can be removed from the coefficient matrix. The developed models implemented in a machine-independent computer program form powerful tools, with which the influence of space harmonics in relation to the geometric data of specific motors can be analyzed for steady-state and transient performances.

Base drive and overlap protection circuit

DOEpatents

Gritter, David J.

1983-01-01

An inverter (34) which provides power to an A. C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A. C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A. C. machine is optimized. The control circuit includes a microcomputer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). A base drive and overlap protection circuit is included to insure that both transistors of a complimentary pair are not conducting at the same time. In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

Modifications of the IBM personal computer synchronous communications support programs for use with the Multics

USGS Publications Warehouse

Kork, John O.

1983-01-01

Version 1.00 of the Asynchronous Communications Support supplied with the IBM Personal Computer must be modified to be used for communications with Multics. Version 2.00 can be used as supplied, but error checking and screen printing capabilities can be added by using modifications very similar to those required for Version 1.00. This paper describes and lists required programs on Multics and appropriate modifications to both Versions 1.00 and 2.00 of the programs supplied by IBM.

An Autonomous Wireless Sensor Node With Asynchronous ECG Monitoring in 0.18 μ m CMOS.

PubMed

Mansano, Andre L; Li, Yongjia; Bagga, Sumit; Serdijn, Wouter A

2016-06-01

The design of a 13.56 MHz/402 MHz autonomous wireless sensor node with asynchronous ECG monitoring for near field communication is presented. The sensor node consists of an RF energy harvester (RFEH), a power management unit, an ECG readout, a data encoder and an RF backscattering transmitter. The energy harvester supplies the system with 1.25 V and offers a power conversion efficiency of 19% from a -13 dBm RF source at 13.56 MHz. The power management unit regulates the output voltage of the RFEH to supply the ECG readout with VECG = 0.95 V and the data encoder with VDE = 0.65 V . The ECG readout comprises an analog front-end (low noise amplifier and programmable voltage to current converter) and an asynchronous level crossing ADC with 8 bits resolution. The ADC output is encoded by a pulse generator that drives a backscattering transmitter at 402 MHz. The total power consumption of the sensor node circuitry is 9.7 μ W for a data rate of 90 kb/s and a heart rate of 70 bpm. The chip has been designed in a 0.18 μm CMOS process and shows superior RF input power sensitivity and lower power consumption when compared to previous works.

The chording effect on core losses of three-phase induction motor under sinusoidal and PWM voltage supplies

NASA Astrophysics Data System (ADS)

Deshmukh, Ram; Moses, A. J.; Anayi, F.

The core losses and the lower-order voltage harmonics of four different chorded motors fed from sinusoidal supply and inverter voltage supply were invigilated at no-load condition. All the four motors were tested with 4, 8 and 16 kHz switching frequencies and 30, 40, 50 and 60 Hz modulation frequencies The motor with 120° coil pitch has the least core losses and the lower-order voltage harmonics under sinusoidal and pulse width modulation (PWM) voltage supplies at all switching and modulation frequencies. The drop in the core losses for this motor was 46% and 53% under sinusoidal and PWM voltage supplies, respectively. The motor with 120° coil pitch is recommended to be used under sinusoidal and PWM voltage supplies.

About increasing informativity of diagnostic system of asynchronous electric motor by extracting additional information from values of consumed current parameter

NASA Astrophysics Data System (ADS)

Zhukovskiy, Y.; Korolev, N.; Koteleva, N.

2018-05-01

This article is devoted to expanding the possibilities of assessing the technical state of the current consumption of asynchronous electric drives, as well as increasing the information capacity of diagnostic methods, in conditions of limited access to equipment and incompleteness of information. The method of spectral analysis of the electric drive current can be supplemented by an analysis of the components of the current of the Park's vector. The research of the hodograph evolution in the moment of appearance and development of defects was carried out using the example of current asymmetry in the phases of an induction motor. The result of the study is the new diagnostic parameters of the asynchronous electric drive. During the research, it was proved that the proposed diagnostic parameters allow determining the type and level of the defect. At the same time, there is no need to stop the equipment and taky it out of service for repair. Modern digital control and monitoring systems can use the proposed parameters based on the stator current of an electrical machine to improve the accuracy and reliability of obtaining diagnostic patterns and predicting their changes in order to improve the equipment maintenance systems. This approach can also be used in systems and objects where there are significant parasitic vibrations and unsteady loads. The extraction of useful information can be carried out in electric drive systems in the structure of which there is a power electric converter.

Rate and Timing Precision of Motor Coordination in Developmental Dyslexia.

ERIC Educational Resources Information Center

Wolff, Peter H.; And Others

1990-01-01

Adolescents and young adults with developmental dyslexia and matched normal and disabled controls were asked to tap in time to a metronome at three rates by moving the index fingers of both hands in unison, in rhythmical alternation, or in more complex bimanual patterns. Dyslexic subjects showed significant deficits on asynchronous, but not…

DC Motor control using motor-generator set with controlled generator field

DOEpatents

Belsterling, Charles A.; Stone, John

1982-01-01

A d.c. generator is connected in series opposed to the polarity of a d.c. power source supplying a d.c. drive motor. The generator is part of a motor-generator set, the motor of which is supplied from the power source connected to the motor. A generator field control means varies the field produced by at least one of the generator windings in order to change the effective voltage output. When the generator voltage is exactly equal to the d.c. voltage supply, no voltage is applied across the drive motor. As the field of the generator is reduced, the drive motor is supplied greater voltage until the full voltage of the d.c. power source is supplied when the generator has zero field applied. Additional voltage may be applied across the drive motor by reversing and increasing the reversed field on the generator. The drive motor may be reversed in direction from standstill by increasing the generator field so that a reverse voltage is applied across the d.c. motor.

Effects of altered auditory feedback across effector systems: production of melodies by keyboard and singing.

PubMed

Pfordresher, Peter Q; Mantell, James T

2012-01-01

We report an experiment that tested whether effects of altered auditory feedback (AAF) during piano performance differ from its effects during singing. These effector systems differ with respect to the mapping between motor gestures and pitch content of auditory feedback. Whereas this action-effect mapping is highly reliable during phonation in any vocal motor task (singing or speaking), mapping between finger movements and pitch occurs only in limited situations, such as piano playing. Effects of AAF in both tasks replicated results previously found for keyboard performance (Pfordresher, 2003), in that asynchronous (delayed) feedback slowed timing whereas alterations to feedback pitch increased error rates, and the effect of asynchronous feedback was similar in magnitude across tasks. However, manipulations of feedback pitch had larger effects on singing than on keyboard production, suggesting effector-specific differences in sensitivity to action-effect mapping with respect to feedback content. These results support the view that disruption from AAF is based on abstract, effector independent, response-effect associations but that the strength of associations differs across effector systems. Copyright © 2011. Published by Elsevier B.V.

VASA: Interactive Computational Steering of Large Asynchronous Simulation Pipelines for Societal Infrastructure.

PubMed

Ko, Sungahn; Zhao, Jieqiong; Xia, Jing; Afzal, Shehzad; Wang, Xiaoyu; Abram, Greg; Elmqvist, Niklas; Kne, Len; Van Riper, David; Gaither, Kelly; Kennedy, Shaun; Tolone, William; Ribarsky, William; Ebert, David S

2014-12-01

We present VASA, a visual analytics platform consisting of a desktop application, a component model, and a suite of distributed simulation components for modeling the impact of societal threats such as weather, food contamination, and traffic on critical infrastructure such as supply chains, road networks, and power grids. Each component encapsulates a high-fidelity simulation model that together form an asynchronous simulation pipeline: a system of systems of individual simulations with a common data and parameter exchange format. At the heart of VASA is the Workbench, a visual analytics application providing three distinct features: (1) low-fidelity approximations of the distributed simulation components using local simulation proxies to enable analysts to interactively configure a simulation run; (2) computational steering mechanisms to manage the execution of individual simulation components; and (3) spatiotemporal and interactive methods to explore the combined results of a simulation run. We showcase the utility of the platform using examples involving supply chains during a hurricane as well as food contamination in a fast food restaurant chain.

Motor disorders of the oesophagus in gastro-oesophageal reflux.

PubMed Central

Mahony, M J; Migliavacca, M; Spitz, L; Milla, P J

1988-01-01

Mechanisms of gastro-oesophageal reflux were studied by oesophageal manometry and pH monitoring in 33 children: nine controls, 15 with gastro-oesophageal reflux alone, and nine with reflux oesophagitis. A total of 122 episodes of reflux were analysed in detail: 82 (67%) were synchronous with swallowing and 40 (33%) asynchronous. Infants with trivial symptoms had gastro-oesophageal reflux synchronous with swallowing, whereas those with serious symptoms had slower acid clearance and asynchronous reflux. There were significant differences in lower oesophageal sphincter pressure and amplitude of oesophageal contractions between controls and patients with both gastro-oesophageal reflux and reflux oesophagitis. In reflux oesophagitis there was a decrease in lower oesophageal sphincter pressure and the contractions had a bizarre waveform suggesting a neuropathic process. PMID:3202640

Robotic goalie with 3 ms reaction time at 4% CPU load using event-based dynamic vision sensor

PubMed Central

Delbruck, Tobi; Lang, Manuel

2013-01-01

Conventional vision-based robotic systems that must operate quickly require high video frame rates and consequently high computational costs. Visual response latencies are lower-bound by the frame period, e.g., 20 ms for 50 Hz frame rate. This paper shows how an asynchronous neuromorphic dynamic vision sensor (DVS) silicon retina is used to build a fast self-calibrating robotic goalie, which offers high update rates and low latency at low CPU load. Independent and asynchronous per pixel illumination change events from the DVS signify moving objects and are used in software to track multiple balls. Motor actions to block the most “threatening” ball are based on measured ball positions and velocities. The goalie also sees its single-axis goalie arm and calibrates the motor output map during idle periods so that it can plan open-loop arm movements to desired visual locations. Blocking capability is about 80% for balls shot from 1 m from the goal even with the fastest-shots, and approaches 100% accuracy when the ball does not beat the limits of the servo motor to move the arm to the necessary position in time. Running with standard USB buses under a standard preemptive multitasking operating system (Windows), the goalie robot achieves median update rates of 550 Hz, with latencies of 2.2 ± 2 ms from ball movement to motor command at a peak CPU load of less than 4%. Practical observations and measurements of USB device latency are provided1. PMID:24311999

Block-Module Electric Machines of Alternating Current

NASA Astrophysics Data System (ADS)

Zabora, I.

2018-03-01

The paper deals with electric machines having active zone based on uniform elements. It presents data on disk-type asynchronous electric motors with short-circuited rotors, where active elements are made by integrated technique that forms modular elements. Photolithography, spraying, stamping of windings, pressing of core and combined methods are utilized as the basic technological approaches of production. The constructions and features of operation for new electric machine - compatible electric machines-transformers are considered. Induction motors are intended for operation in hermetic plants with extreme conditions surrounding gas, steam-to-gas and liquid environment at a high temperature (to several hundred of degrees).

Multiple-input single-output closed-loop isometric force control using asynchronous intrafascicular multi-electrode stimulation.

PubMed

Frankel, Mitchell A; Dowden, Brett R; Mathews, V John; Normann, Richard A; Clark, Gregory A; Meek, Sanford G

2011-06-01

Although asynchronous intrafascicular multi-electrode stimulation (IFMS) can evoke fatigue-resistant muscle force, a priori determination of the necessary stimulation parameters for precise force production is not possible. This paper presents a proportionally-modulated, multiple-input single-output (MISO) controller that was designed and experimentally validated for real-time, closed-loop force-feedback control of asynchronous IFMS. Experiments were conducted on anesthetized felines with a Utah Slanted Electrode Array implanted in the sciatic nerve, either acutely or chronically ( n = 1 for each). Isometric forces were evoked in plantar-flexor muscles, and target forces consisted of up to 7 min of step, sinusoidal, and more complex time-varying trajectories. The controller was successful in evoking steps in force with time-to-peak of less than 0.45 s, steady-state ripple of less than 7% of the mean steady-state force, and near-zero steady-state error even in the presence of muscle fatigue, but with transient overshoot of near 20%. The controller was also successful in evoking target sinusoidal and complex time-varying force trajectories with amplitude error of less than 0.5 N and time delay of approximately 300 ms. This MISO control strategy can potentially be used to develop closed-loop asynchronous IFMS controllers for a wide variety of multi-electrode stimulation applications to restore lost motor function.

Impacts of P-f & Q-V Droop Control on MicroGrids Transient Stability

NASA Astrophysics Data System (ADS)

Zhao-xia, Xiao; Hong-wei, Fang

Impacts of P-f & Q-V droop control on MicroGrid transient stability was investigated with a wind unit of asynchronous generator in the MicroGrid. The system frequency stability was explored when the motor load starts and its load power changes, and faults of different types and different locations occurs. The simulations were done by PSCAD/EMTDC.

On the asynchronously continuous control of mobile robot movement by motor cortical spiking activity.

PubMed

Xu, Zhiming; So, Rosa Q; Toe, Kyaw Kyar; Ang, Kai Keng; Guan, Cuntai

2014-01-01

This paper presents an asynchronously intracortical brain-computer interface (BCI) which allows the subject to continuously drive a mobile robot. This system has a great implication for disabled patients to move around. By carefully designing a multiclass support vector machine (SVM), the subject's self-paced instantaneous movement intents are continuously decoded to control the mobile robot. In particular, we studied the stability of the neural representation of the movement directions. Experimental results on the nonhuman primate showed that the overt movement directions were stably represented in ensemble of recorded units, and our SVM classifier could successfully decode such movements continuously along the desired movement path. However, the neural representation of the stop state for the self-paced control was not stably represented and could drift.

Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

PubMed

Marisa, T; Niederhauser, T; Haeberlin, A; Wildhaber, R A; Vogel, R; Goette, J; Jacomet, M

2017-02-07

A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing. The architecture offers the advantages of smaller chip area, energy saving and fewer analogue system components. Beside lower energy consumption the use of dynamic comparators results in a more robust performance in noise conditions. Moreover, dynamic comparators make interfacing the asynchronous level crossing system to synchronous processing blocks simpler. The proposed adc was implemented in [Formula: see text] complementary metal-oxide-semiconductor (cmos) technology, the hardware occupies a chip area of 0.0372 mm 2 and operates from a supply voltage of [Formula: see text] to [Formula: see text]. The adc's power consumption is as low as 0.6 μW with signal bandwidth from [Formula: see text] to [Formula: see text] and achieves an equivalent number of bits (enob) of up to 8 bits.

[Ecosystem services supply and consumption and their relationships with human well-being].

PubMed

Wang, Da-Shang; Zheng, Hua; Ouyang, Zhi-Yun

2013-06-01

Sustainable ecosystem services supply is the basis of regional sustainable development, and human beings can satisfy and improve their well-being through ecosystem services consumption. To understand the relationships between ecosystem services supply and consumption and human well-being is of vital importance for coordinating the relationships between the conservation of ecosystem services and the improvement of human well-being. This paper summarized the diversity, complexity, and regionality of ecosystem services supply, the diversity and indispensability of ecosystem services consumption, and the multi-dimension, regionality, and various evaluation indices of human well-being, analyzed the uncertainty and multi-scale correlations between ecosystem services supply and consumption, and elaborated the feedback and asynchronous relationships between ecosystem services and human well-being. Some further research directions for the relationships between ecosystem services supply and consumption and human well-being were recommended.

Nitrogen recycling through the gut and the nitrogen economy of ruminants: an asynchronous symbiosis.

PubMed

Reynolds, C K; Kristensen, N B

2008-04-01

The extensive development of the ruminant forestomach sets apart their N economy from that of nonruminants in a number of respects. Extensive pregastric fermentation alters the profile of protein reaching the small intestine, largely through the transformation of nitrogenous compounds into microbial protein. This process is fueled primarily by carbohydrate fermentation and includes extensive recycling of N between the body and gut lumen pools. Nitrogen recycling occurs via blood and gut lumen exchanges of urea and NH(3), as well as endogenous gut and secretory N entry into the gut lumen, and the subsequent digestion and absorption of microbial and endogenous protein. Factors controlling urea transfer to the gut from blood, including the contributions of urea transporters, remain equivocal. Ammonia produced by microbial degradation of urea and dietary and endogenous AA is utilized by microbial fermentation or absorbed and primarily converted to urea. Therefore, microbial growth and carbohydrate fermentation affect the extent of NH(3) absorption and urea N recycling and excretion. The extensive recycling of N to the rumen represents an evolutionary advantage of the ruminant in terms of absorbable protein supply during periods of dietary protein deficiency, or asynchronous carbohydrate and protein supply, but incurs a cost of greater N intakes, especially in terms of excess N excretion. Efforts to improve the efficiency of N utilization in ruminants by synchronizing fermentable energy and N availability have generally met with limited success with regards to production responses. In contrast, imposing asynchrony through oscillating dietary protein concentration, or infrequent supplementation, surprisingly has not negatively affected production responses unless the frequency of supplementation is less than once every 3 d. In some cases, oscillation of dietary protein concentration has improved N retention compared with animals fed an equal amount of dietary protein on a daily basis. This may reflect benefits of Orn cycle adaptations and sustained recycling of urea to the gut. The microbial symbiosis of the ruminant is inherently adaptable to asynchronous N and energy supply. Recycling of urea to the gut buffers the effect of irregular dietary N supply such that intuitive benefits of rumen synchrony in terms of the efficiency of N utilization are typically not observed in practice.

Similar brain networks for detecting visuo-motor and visuo-proprioceptive synchrony.

PubMed

Balslev, Daniela; Nielsen, Finn A; Lund, Torben E; Law, Ian; Paulson, Olaf B

2006-05-15

The ability to recognize feedback from own movement as opposed to the movement of someone else is important for motor control and social interaction. The neural processes involved in feedback recognition are incompletely understood. Two competing hypotheses have been proposed: the stimulus is compared with either (a) the proprioceptive feedback or with (b) the motor command and if they match, then the external stimulus is identified as feedback. Hypothesis (a) predicts that the neural mechanisms or brain areas involved in distinguishing self from other during passive and active movement are similar, whereas hypothesis (b) predicts that they are different. In this fMRI study, healthy subjects saw visual cursor movement that was either synchronous or asynchronous with their active or passive finger movements. The aim was to identify the brain areas where the neural activity depended on whether the visual stimulus was feedback from own movement and to contrast the functional activation maps for active and passive movement. We found activity increases in the right temporoparietal cortex in the condition with asynchronous relative to synchronous visual feedback from both active and passive movements. However, no statistically significant difference was found between these sets of activated areas when the active and passive movement conditions were compared. With a posterior probability of 0.95, no brain voxel had a contrast effect above 0.11% of the whole-brain mean signal. These results do not support the hypothesis that recognition of visual feedback during active and passive movement relies on different brain areas.

Asynchronous brain-computer interface for cognitive assessment in people with cerebral palsy

NASA Astrophysics Data System (ADS)

Alcaide-Aguirre, R. E.; Warschausky, S. A.; Brown, D.; Aref, A.; Huggins, J. E.

2017-12-01

Objective. Typically, clinical measures of cognition require motor or speech responses. Thus, a significant percentage of people with disabilities are not able to complete standardized assessments. This situation could be resolved by employing a more accessible test administration method, such as a brain-computer interface (BCI). A BCI can circumvent motor and speech requirements by translating brain activity to identify a subject’s response. By eliminating the need for motor or speech input, one could use a BCI to assess an individual who previously did not have access to clinical tests. Approach. We developed an asynchronous, event-related potential BCI-facilitated administration procedure for the peabody picture vocabulary test (PPVT-IV). We then tested our system in typically developing individuals (N  =  11), as well as people with cerebral palsy (N  =  19) to compare results to the standardized PPVT-IV format and administration. Main results. Standard scores on the BCI-facilitated PPVT-IV, and the standard PPVT-IV were highly correlated (r  =  0.95, p  <  0.001), with a mean difference of 2.0  ±  6.4 points, which is within the standard error of the PPVT-IV. Significance. Thus, our BCI-facilitated PPVT-IV provided comparable results to the standard PPVT-IV, suggesting that populations for whom standardized cognitive tests are not accessible could benefit from our BCI-facilitated approach.

Pulse-Width-Modulating Driver for Brushless dc Motor

NASA Technical Reports Server (NTRS)

Salomon, Phil M.

1991-01-01

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

The analysis of 3-phase squirrel-cage induction motors including space harmonics and mutual slotting in transient and steady state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paap, G.C.

1991-03-01

From general equations which describe the transient electromechanical behavior of the asynchronous squirrel-cage motor, and which include the influence of space harmonics and mutual slotting, simplified models are derived and compared. The models derived are demonstrated in examples where special attention is paid to the influence of the place of the harmonics in the mutual inductance matrix and the influence of mutual slotting. Further, the steady-state equations are derived and the back-transformation for the stator and rotor currents is given. One example is compared with the result of measurements.

Asynchronous machine rotor speed estimation using a tabulated numerical approach

NASA Astrophysics Data System (ADS)

Nguyen, Huu Phuc; De Miras, Jérôme; Charara, Ali; Eltabach, Mario; Bonnet, Stéphane

2017-12-01

This paper proposes a new method to estimate the rotor speed of the asynchronous machine by looking at the estimation problem as a nonlinear optimal control problem. The behavior of the nonlinear plant model is approximated off-line as a prediction map using a numerical one-step time discretization obtained from simulations. At each time-step, the speed of the induction machine is selected satisfying the dynamic fitting problem between the plant output and the predicted output, leading the system to adopt its dynamical behavior. Thanks to the limitation of the prediction horizon to a single time-step, the execution time of the algorithm can be completely bounded. It can thus easily be implemented and embedded into a real-time system to observe the speed of the real induction motor. Simulation results show the performance and robustness of the proposed estimator.

Axonal flip-flops and oscillators.

PubMed

Baker, M D

2000-11-01

The strange and unpleasant sensations (paraesthesiae) or asynchronous motor-unit activation (fasciculation) that result from a period of limb ischaemia are examples of ectopic discharge in peripheral nerves. Ectopic activity also results from demyelination and is associated with serious neurological conditions, such as multiple sclerosis. A build-up of extracellular K(+) in the internode and persistent Na(+) currents are now implicated in generating the different forms of activity arising in normal and demyelinated axons.

Comparaison de méthodes d'identification des paramètres d'une machine asynchrone

NASA Astrophysics Data System (ADS)

Bellaaj-Mrabet, N.; Jelassi, K.

1998-07-01

Interests, in Genetic Algorithms (G.A.) expands rapidly. This paper consists initially to apply G.A. for identifying induction motor parameters. Next, we compare the performances with classical methods like Maximum Likelihood and classical electrotechnical methods. These methods are applied on three induction motors of different powers to compare results following a set of criteria. Les algorithmes génétiques sont des méthodes adaptatives de plus en plus utilisée pour la résolution de certains problèmes d'optimisation. Le présent travail consiste d'une part, à mettre en œuvre un A.G sur des problèmes d'identification des machines électriques, et d'autre part à comparer ses performances avec les méthodes classiques tels que la méthode du maximum de vraisemblance et la méthode électrotechnique basée sur des essais à vides et en court-circuit. Ces méthodes sont appliquées sur des machines asynchrones de différentes puissances. Les résultats obtenus sont comparés selon certains critères, permettant de conclure sur la validité et la performance de chaque méthode.

High power-efficient asynchronous SAR ADC for IoT devices

NASA Astrophysics Data System (ADS)

Zhang, Beichen; Yao, Bingbing; Liu, Liyuan; Liu, Jian; Wu, Nanjian

2017-10-01

This paper presents a power-efficient 100-MS/s, 10-bit asynchronous successive approximation register (SAR) ADC. It includes an on-chip reference buffer and the total power dissipation is 6.8 mW. To achieve high performance with high power-efficiency in the proposed ADC, bootstrapped switch, redundancy, set-and-down switching approach, dynamic comparator and dynamic logic techniques are employed. The prototype was fabricated using 65 nm standard CMOS technology. At a 1.2-V supply and 100 MS/s, the ADC achieves an SNDR of 56.2 dB and a SFDR of 65.1 dB. The ADC core consumes only 3.1 mW, resulting in a figure of merit (FOM) of 30.27 fJ/conversionstep and occupies an active area of only 0.009 mm2.

Compressor-fan unitary structure for air conditioning system

NASA Astrophysics Data System (ADS)

Dreiman, N.

2015-08-01

An extremely compact, therefore space saving unitary structure of short axial length is produced by radial integration of a revolving piston rotary compressor and an impeller of a centrifugal fan. The unitary structure employs single motor to run as the compressor so the airflow fan and eliminates duality of motors, related power supply and control elements. Novel revolving piston rotary compressor which provides possibility for such integration comprises the following: a suction gas delivery system which provides cooling of the motor and supplies refrigerant into the suction chamber under higher pressure (supercharged); a modified discharge system and lubricating oil supply system. Axial passages formed in the stationary crankshaft are used to supply discharge gas to a condenser, to return vaporized cooling agent from the evaporator to the suction cavity of the compressor, to pass a lubricant and to accommodate wiring supplying power to the unitary structure driver -external rotor electric motor.

Effect of different methods of pulse width modulation on power losses in an induction motor

NASA Astrophysics Data System (ADS)

Gulyaev, Alexander; Fokin, Dmitrii; Shuharev, Sergey; Ten, Evgenii

2017-10-01

We consider the calculation of modulation power losses in a system “induction motor-inverter” for various pulse width modulation (PWM) methods of the supply voltage. Presented values of modulation power losses are the result of modeling a system “DC link - two-level three-phase voltage inverter - induction motor - load”. In this study the power losses in a system “induction motor - inverter” are computed, as well as losses caused by higher harmonics of PWM supply voltage, followed by definition of active power consumed by the DC link for a specified value mechanical power on the induction motor shaft. Mechanical power was determined by the rotation speed and the torque on the motor shaft in various quasi-sinusoidal supply voltage PWM modes. These calculations reveal the best coefficient of performance (COP) in a system of a variable frequency drive (VFD) with independent voltage inverter controlled by induction motor PWM.

Simulation of three-phase induction motor drives using indirect field oriented control in PSIM environment

NASA Astrophysics Data System (ADS)

Aziri, Hasif; Patakor, Fizatul Aini; Sulaiman, Marizan; Salleh, Zulhisyam

2017-09-01

This paper presents the simulation of three-phase induction motor drives using Indirect Field Oriented Control (IFOC) in PSIM environment. The asynchronous machine is well known about natural limitations fact of highly nonlinearity and complexity of motor model. In order to resolve these problems, the IFOC is applied to control the instantaneous electrical quantities such as torque and flux component. As FOC is controlling the stator current that represented by a vector, the torque component is aligned with d coordinate while the flux component is aligned with q coordinate. There are five levels of the incremental system are gradually built up to verify and testing the software module in the system. Indeed, all of system build levels are verified and successfully tested in PSIM environment. Moreover, the corresponding system of five build levels are simulated in PSIM environment which is user-friendly for simulation studies in order to explore the performance of speed responses based on IFOC algorithm for three-phase induction motor drives.

On the role of cost-sensitive learning in multi-class brain-computer interfaces.

PubMed

Devlaminck, Dieter; Waegeman, Willem; Wyns, Bart; Otte, Georges; Santens, Patrick

2010-06-01

Brain-computer interfaces (BCIs) present an alternative way of communication for people with severe disabilities. One of the shortcomings in current BCI systems, recently put forward in the fourth BCI competition, is the asynchronous detection of motor imagery versus resting state. We investigated this extension to the three-class case, in which the resting state is considered virtually lying between two motor classes, resulting in a large penalty when one motor task is misclassified into the other motor class. We particularly focus on the behavior of different machine-learning techniques and on the role of multi-class cost-sensitive learning in such a context. To this end, four different kernel methods are empirically compared, namely pairwise multi-class support vector machines (SVMs), two cost-sensitive multi-class SVMs and kernel-based ordinal regression. The experimental results illustrate that ordinal regression performs better than the other three approaches when a cost-sensitive performance measure such as the mean-squared error is considered. By contrast, multi-class cost-sensitive learning enables us to control the number of large errors made between two motor tasks.

75 FR 77666 - General Motors Company, Formerly Known as General Motors Corporation, Technical Center, Including...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-13

.../Professional Services, Excluding Workers of the Global Purchasing and Supply Chain Division, Warren, MI...., and Tek Systems, excluding workers of the Global Purchasing and Supply Chain Division, Warren... Purchasing and Supply Chain Division, Warren, Michigan, who became totally or partially separated from...

Definition of Static Voltage Characteristics of the Motor Load for the Purpose of Increase in Energy Efficiency of Coal Mines of Kuzbass

NASA Astrophysics Data System (ADS)

Nepsha, Fedor; Efremenko, Vladimir

2017-11-01

The task of determining the static load characteristics is one of the most important tasks, the solution of which is necessary for the correct development of measures to increase the energy efficiency of the Kuzbass coal mines. At present, the influence of electric receivers on the level of consumption of active and reactive power is not taken into account, therefore, the proposed measures to increase the energy efficiency are not optimal. The article analyzes the L-shaped and T-shaped circuit for the replacement of an asynchronous motor (AM), according to the results of which it is determined that the T-shaped replacement scheme is the most accurate for determination of static load characteristics. The authors proposed and implemented in the MATLAB Simulink environment an algorithm for determining the static voltage characteristics of the motor load.

The design of mobile robot control system for the aged and the disabled

NASA Astrophysics Data System (ADS)

Qiang, Wang; Lei, Shi; Xiang, Gao; Jin, Zhang

2017-01-01

This paper designs a control system of mobile robot for the aged and the disabled, which consists of two main parts: human-computer interaction and drive control module. The data of the two parts is transferred via universal asynchronous receiver/transmitter. In the former part, the speed and direction information of the mobile robot is obtained by hall joystick. In the latter part, the electronic differential algorithm is developed to implement the robot mobile function by driving two-wheel motors. In order to improve the comfort of the robot when speed or direction is changed, the least squares algorithm is used to optimize the speed characteristic curves of the two motors. Experimental results have verified the effectiveness of the designed system.

Toward characterization of Huber's ball-bearing motor

NASA Astrophysics Data System (ADS)

Choo, Joo Liang; Soong, Wen Liang; Abbott, Derek

2005-02-01

A motor that can be powered up by either a DC or AC supply and rotates in either direction, based on the so-called Huber effect, is investigated. For the first time, this paper examines the motor characteristics under both DC and AC conditions, for quantitative comparisons. Earlier work has not examined, in detail, the effect of an AC supply on the Huber motor operation. Previous work on the Huber or ball-bearing motor suffered from alignment problems and here we describe a new methodology to address this. The new construction is also a step toward a micromotor realization. The motor, with its reduced dimensions, also has the advantage of reduced operating current. Since 1959, the principle of operation of this motor has remained an unsolved mystery and various theories exist in the literature. We show various empirical findings that shed some light on the hotly contested debate. The discovery of carbon on the bearings, under AC supply conditions, reported here creates a new open question. Motor acceleration versus torque characteristics are obtained, using a data acquisition system to facilitate dynamic real-time recording.

Magnetic Random Access Memory based non-volatile asynchronous Muller cell for ultra-low power autonomous applications

NASA Astrophysics Data System (ADS)

Di Pendina, G.; Zianbetov, E.; Beigne, E.

2015-05-01

Micro and nano electronic integrated circuit domain is today mainly driven by the advent of the Internet of Things for which the constraints are strong, especially in terms of power consumption and autonomy, not only during the computing phases but also during the standby or idle phases. In such ultra-low power applications, the circuit has to meet new constraints mainly linked to its changing energetic environment: long idle phases, automatic wake up, data back-up when the circuit is sporadically turned off, and ultra-low voltage power supply operation. Such circuits have to be completely autonomous regarding their unstable environment, while remaining in an optimum energetic configuration. Therefore, we propose in this paper the first MRAM-based non-volatile asynchronous Muller cell. This cell has been simulated and characterized in a very advanced 28 nm CMOS fully depleted silicon-on-insulator technology, presenting good power performance results due to an extremely efficient body biasing control together with ultra-wide supply voltage range from 160 mV up to 920 mV. The leakage current can be reduced to 154 pA thanks to reverse body biasing. We also propose an efficient standard CMOS bulk version of this cell in order to be compatible with different fabrication processes.

76 FR 34192 - Commercial and Industrial Pumps

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-13

... 1999. The ADL analysis, ``Energy Consumption Characteristics of Commercial Building HVAC Systems... report for the United Nations (``Motor System Efficiency Supply Curves UNIDO,'' Dec. 2010),\\3\\ also used..., A. and A. Hasanbeigi, ``Motor Systems Efficiency Supply Curves,'' United Nations Industrial...

Fault diagnosis and fault-tolerant finite control set-model predictive control of a multiphase voltage-source inverter supplying BLDC motor.

PubMed

Salehifar, Mehdi; Moreno-Equilaz, Manuel

2016-01-01

Due to its fault tolerance, a multiphase brushless direct current (BLDC) motor can meet high reliability demand for application in electric vehicles. The voltage-source inverter (VSI) supplying the motor is subjected to open circuit faults. Therefore, it is necessary to design a fault-tolerant (FT) control algorithm with an embedded fault diagnosis (FD) block. In this paper, finite control set-model predictive control (FCS-MPC) is developed to implement the fault-tolerant control algorithm of a five-phase BLDC motor. The developed control method is fast, simple, and flexible. A FD method based on available information from the control block is proposed; this method is simple, robust to common transients in motor and able to localize multiple open circuit faults. The proposed FD and FT control algorithm are embedded in a five-phase BLDC motor drive. In order to validate the theory presented, simulation and experimental results are conducted on a five-phase two-level VSI supplying a five-phase BLDC motor. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System.

PubMed

Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

2016-08-18

Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems.

10 CFR 431.62 - Definitions concerning commercial refrigerators, freezers and refrigerator-freezers.

Code of Federal Regulations, 2012 CFR

2012-01-01

... transparent or solid doors, sliding or hinged doors, a combination of hinged, sliding, transparent, or solid... compressors, refrigerant condensers, condenser fans and motors, and factory supplied accessories. Self... more refrigerant compressors, refrigerant condensers, condenser fans and motors, and factory supplied...

Study of Contactless Power Supply for Spindle Ultrasonic Vibrator

NASA Astrophysics Data System (ADS)

Chen, T. R.; Lee, Y. L.; Liu, H. T.; Chen, S. M.; Chang, H. Z.

2017-11-01

In this study, a contactless power supply for the ultrasonic motor on the spindle is proposed. The proposed power supply is composed of a series-parallel resonant circuit and a cylindrical contactless transformer. Based on the study and rotation experiments, it can be seen that the proposed power supply can both provide a stable ac power with 25 kHz / 70 V to the ultrasonic motor. When the output power is 250 W, the efficiency of the proposed supply is 89.8 % in respectively rotation tests. When the output power is more than 150 W, the efficiency of the proposed supply is higher than 80 % within the rated output power range.

Pulvinar thalamic nucleus allows for asynchronous spike propagation through the cortex

PubMed Central

Cortes, Nelson; van Vreeswijk, Carl

2015-01-01

We create two multilayered feedforward networks composed of excitatory and inhibitory integrate-and-fire neurons in the balanced state to investigate the role of cortico-pulvino-cortical connections. The first network consists of ten feedforward levels where a Poisson spike train with varying firing rate is applied as an input in layer one. Although the balanced state partially avoids spike synchronization during the transmission, the average firing-rate in the last layer either decays or saturates depending on the feedforward pathway gain. The last layer activity is almost independent of the input even for a carefully chosen intermediate gain. Adding connections to the feedforward pathway by a nine areas Pulvinar structure improves the firing-rate propagation to become almost linear among layers. Incoming strong pulvinar spikes balance the low feedforward gain to have a unit input-output relation in the last layer. Pulvinar neurons evoke a bimodal activity depending on the magnitude input: synchronized spike bursts between 20 and 80 Hz and an asynchronous activity for very both low and high frequency inputs. In the first regime, spikes of last feedforward layer neurons are asynchronous with weak, low frequency, oscillations in the rate. Here, the uncorrelated incoming feedforward pathway washes out the synchronized thalamic bursts. In the second regime, spikes in the whole network are asynchronous. As the number of cortical layers increases, long-range pulvinar connections can link directly two or more cortical stages avoiding their either saturation or gradual activity falling. The Pulvinar acts as a shortcut that supplies the input-output firing-rate relationship of two separated cortical areas without changing the strength of connections in the feedforward pathway. PMID:26042026

Permanent split capacitor single phase electric motor system

DOEpatents

Kirschbaum, Herbert S.

1984-01-01

A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation.

Overview of 10 inch Diameter HTPB Hybrid Motor Testing with Liquid Oxygen at Stennis Space Center

NASA Technical Reports Server (NTRS)

Knowles, Timothy E.; Kearney, Darren; Roberts, Ryan

2005-01-01

To further explore the operation of hybrid rocket motors and to demonstrate the performance characteristics of the motor design Lockheed Martin funded research on a series of 10 inch diameter hybrid motors that produce less than 10 klbf sea level thrust. This test series was given the name "Hybrid Technology Test Program." These motors were fired in the existing test stand at the SSC E-3 complex Cell 1. The fuel and oxidizer for these 10 inch diameter motors are HTPB and LO2, respectively. The original goal of the testing was to verify that the predicted performance matched the actual performance of these 10 inch motors (ref. figure 1) and then confirm that the motors performed acceptably. For this element of testing horizontally fired hybrid motors will be tested using LO2 supplied from the existing facility 100 gallon LO2 tank that is pressurized with facility GN2. The thrust produced by the motor will be measured by a Lockheed Martin supplied load cell.

Study on the dynamics responses of a transmission system made from carbon nanotubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yin, Hang; Cai, Kun, E-mail: kuicansj@163.com; Wei, Ning

2015-06-21

A rotational transmission system from coaxial carbon nanotubes (CNTs) is investigated using a computational molecular dynamics approach. The system consists of a motor from a single-walled carbon nanotube and a bearing from a double-walled carbon nanotube. The motor has a high fixed rotational frequency and the two ends of the outer tube in the bearing are fixed. The inner tube in the bearing works as a rotor. Because of the interlayer friction in the bearing, configurations of the joint between the adjacent ends of motor and rotor have significant effects on rotational transmission properties. Four factors are considered in simulation,more » i.e., the bonding types of atoms (sp{sup 1} and sp{sup 2}) on the ends of motor and rotor, the difference between motor and rotor radii, the rotational speed of motor, and the environmental temperature. It is found that the synchronous transmission happens if the sp{sup 1} atoms on the jointed ends of motor and rotor are bonded each other and become new sp{sup 2} atoms. Therefore, the lower difference between radii of motor and rotor, higher temperature of environment leads to synchronous rotational transmission easily. If the environmental temperature is too low (e.g., <150 K), the end of motor adjacent to rotor is easily under buckling and new sp{sup 2} atoms appear, too. With capped CNTs or higher radii difference between rotor and motor at an appropriate temperature, a stable asynchronous rotation of rotor can be generated, and the rotor's frequency varying linearly with motor's frequency between 230 and 270 GHz. A multi-signal transmission device combined with oscillating and rotational motion is proposed for motor and stator shares a same size in radius.« less

Magnetic Random Access Memory based non-volatile asynchronous Muller cell for ultra-low power autonomous applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Pendina, G., E-mail: gregory.dipendina@cea.fr, E-mail: eldar.zianbetov@cea.fr, E-mail: edith.beigne@cea.fr; Zianbetov, E., E-mail: gregory.dipendina@cea.fr, E-mail: eldar.zianbetov@cea.fr, E-mail: edith.beigne@cea.fr; CNRS, SPINTEC, F-38000 Grenoble

2015-05-07

Micro and nano electronic integrated circuit domain is today mainly driven by the advent of the Internet of Things for which the constraints are strong, especially in terms of power consumption and autonomy, not only during the computing phases but also during the standby or idle phases. In such ultra-low power applications, the circuit has to meet new constraints mainly linked to its changing energetic environment: long idle phases, automatic wake up, data back-up when the circuit is sporadically turned off, and ultra-low voltage power supply operation. Such circuits have to be completely autonomous regarding their unstable environment, while remainingmore » in an optimum energetic configuration. Therefore, we propose in this paper the first MRAM-based non-volatile asynchronous Muller cell. This cell has been simulated and characterized in a very advanced 28 nm CMOS fully depleted silicon-on-insulator technology, presenting good power performance results due to an extremely efficient body biasing control together with ultra-wide supply voltage range from 160 mV up to 920 mV. The leakage current can be reduced to 154 pA thanks to reverse body biasing. We also propose an efficient standard CMOS bulk version of this cell in order to be compatible with different fabrication processes.« less

47 CFR 32.1220 - Inventories.

Code of Federal Regulations, 2013 CFR

2013-10-01

... stock including plant supplies, motor vehicles supplies, tools, fuel, other supplies and material and... reporting purposes, as appropriate, in accordance with generally accepted accounting principles. The...

47 CFR 32.1220 - Inventories.

Code of Federal Regulations, 2011 CFR

2011-10-01

... stock including plant supplies, motor vehicles supplies, tools, fuel, other supplies and material and... reporting purposes, as appropriate, in accordance with generally accepted accounting principles. The...

47 CFR 32.1220 - Inventories.

Code of Federal Regulations, 2012 CFR

2012-10-01

... stock including plant supplies, motor vehicles supplies, tools, fuel, other supplies and material and... reporting purposes, as appropriate, in accordance with generally accepted accounting principles. The...

47 CFR 32.1220 - Inventories.

Code of Federal Regulations, 2014 CFR

2014-10-01

... stock including plant supplies, motor vehicles supplies, tools, fuel, other supplies and material and... reporting purposes, as appropriate, in accordance with generally accepted accounting principles. The...

Huffman scanning: using language models within fixed-grid keyboard emulation☆

PubMed Central

Roark, Brian; Beckley, Russell; Gibbons, Chris; Fried-Oken, Melanie

2012-01-01

Individuals with severe motor impairments commonly enter text using a single binary switch and symbol scanning methods. We present a new scanning method –Huffman scanning – which uses Huffman coding to select the symbols to highlight during scanning, thus minimizing the expected bits per symbol. With our method, the user can select the intended symbol even after switch activation errors. We describe two varieties of Huffman scanning – synchronous and asynchronous –and present experimental results, demonstrating speedups over row/column and linear scanning. PMID:24244070

Permanent split capacitor single phase electric motor system

DOEpatents

Kirschbaum, H.S.

1984-08-14

A permanent split capacitor single phase electric motor achieves balanced operation at more than one operating point by adjusting the voltage supplied to the main and auxiliary windings and adjusting the capacitance in the auxiliary winding circuit. An intermediate voltage tap on an autotransformer supplies voltage to the main winding for low speed operation while a capacitive voltage divider is used to adjust the voltage supplied to the auxiliary winding for low speed operation. 4 figs.

Bi-directional four quadrant (BDQ4) power converter development

NASA Technical Reports Server (NTRS)

Schwarz, F. C.

1979-01-01

The feasibility for implementation of a concept for direct ac/dc multikilowatt power conversion with bidirectional transfer of energy was investigated. A 10 kHz current carrier was derived directly from a common 60 Hz three phase power system. This carrier was modulated to remove the 360 Hz ripple, inherent in the three phase power supply and then demodulated and processed by a high frequency filter. The resulting dc power was then supplied to a load. The process was implemented without the use of low frequency transformers and filters. This power conversion processes was reversible and can operate in the four quadrants as viewed from any of the two of the converter's ports. Areas of application include: power systems on air and spacecraft; terrestrial traction; integration of solar and wind powered systems with utility networks; HVDC; asynchronous coupling of polyphase networks; heat treatment; industrial machine drives; and power supplies for any use including instrumentation.

Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System

PubMed Central

Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

2016-01-01

Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems. PMID:27548171

Yarn carrier with clutch

NASA Technical Reports Server (NTRS)

Doyne, Richard A. (Inventor); Benson, Rio H. (Inventor); El-Shiekh, Aly (Inventor)

1994-01-01

A yarn carrier apparatus particularly suited for use in braiding machinery or the like due to its capability of continuous yarn feeding and retraction of long lengths of yarn. The yarn carrier apparatus comprises a yarn supply spool which is rotatably mounted within the housing, a spring motor also mounted within the housing and operatively connected to the yarn supply spool through a mechanical transmission assembly which is adapted to multiply rotational movement between the first element of the gear assembly operatively connected to the spring motor and the final element of the gear assembly operatively connected to the yarn supply spool. The spring motor is adapted to tension the yarn during both feeding and retraction thereof, and it is further adapted to periodically rotatably slip within the housing and partially unwind so as to allow for continuous withdrawal of a long length of yarn without the spring motor becoming fully wound and preventing further yarn retraction.

Yarn carrier apparatus for braiding machines and the like

NASA Technical Reports Server (NTRS)

El-Shiekh, Aly (Inventor); Li, Wei (Inventor); Hammad, Mohamed (Inventor)

1992-01-01

A yarn carrier apparatus particularly suited for use in braiding machinery or the like due to its capability of continuous yarn feeding and retraction of long lengths of yarn. The yarn carrier apparatus comprises a yarn supply spool which is rotatably mounted within the housing, a spring motor also mounted within the housing and operatively connected to the yarn supply spool through a mechanical transmission assembly which is adapted to multiply rotational movement between the first element of the gear assembly operatively connected to the spring motor and the final element of the gear assembly operatively connected to the yarn supply spool. The spring motor is adapted to tension the yarn during both feeding and retraction thereof, and it is further adapted to periodically rotatably slip within the housing and partially unwind so as to allow for continuous withdrawal of a long length of yarn without the spring motor becoming fully wound and preventing further yarn retraction.

Development of a software and hardware system for monitoring the air cleaning process using a cyclone-separator

NASA Astrophysics Data System (ADS)

Nicolaeva, B. K.; Borisov, A. P.; Zlochevskiy, V. L.

2017-08-01

The article is devoted to the development of a hardware-software complex for monitoring and controlling the process of air purification by means of a cyclone-separator. The hardware of this complex is the Arduino platform, to which are connected pressure sensors, air velocities, dustmeters, which allow monitoring of the main parameters of the cyclone-separator. Also, a frequency converter was developed to regulate the rotation speed of an asynchronous motor necessary to correct the flow rate, the control signals of which come with Arduino. The program part of the complex is written in the form of a web application in the programming language JavaScript and inserts into CSS and HTML for the user interface. This program allows you to receive data from sensors, build dependencies in real time and control the speed of rotation of an asynchronous electric drive. The conducted experiment shows that the cleaning efficiency is 95-99.9%, while the airflow at the cyclone inlet is 16-18 m/s, and at the exit 50-70 m/s.

Short-Term Energy Outlook Model Documentation: Petroleum Products Supply Module

EIA Publications

2013-01-01

The Petroleum Products Supply Module of the Short-Term Energy Outlook (STEO) model provides forecasts of petroleum refinery inputs (crude oil, unfinished oils, pentanes plus, liquefied petroleum gas, motor gasoline blending components, and aviation gasoline blending components) and refinery outputs (motor gasoline, jet fuel, distillate fuel, residual fuel, liquefied petroleum gas, and other petroleum products).

48 CFR 945.570-2 - Acquisition of motor vehicles.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Acquisition of motor... Acquisition of motor vehicles. (a) The GSA Interagency Fleet Management System (GSA-IFMS) is the first source of supply for providing motor vehicles to contractors; however, contracting officer approval is...

48 CFR 945.570-2 - Acquisition of motor vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Acquisition of motor... Acquisition of motor vehicles. (a) The GSA Interagency Fleet Management System (GSA-IFMS) is the first source of supply for providing motor vehicles to contractors; however, contracting officer approval is...

Energy Efficiency of Induction Motors Running Off Frequency Converters with Pulse-Width Voltage Modulation{sup 1}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shvetsov, N. K., E-mail: elmash@em.ispu.ru

2016-11-15

The results of calculations of the increase in losses in an induction motor with frequency control and different forms of the supply voltage are presented. The calculations were performed by an analytic method based on harmonic analysis of the supply voltage as well as numerical calculation of the electromagnetic processes by the finite-element method.

A portable integrated system to control an active needle

NASA Astrophysics Data System (ADS)

Konh, Bardia; Motalleb, Mahdi; Ashrafiuon, Hashem

2017-04-01

The primary objective of this work is to introduce an integrated portable system to operate a flexible active surgical needle with actuation capabilities. The smart needle uses the robust actuation capabilities of the shape memory alloy wires to drastically improve the accuracy of in medical procedures such as brachytherapy. This, however, requires an integrated system aimed to control the insertion of the needle via a linear motor and its deflection by the SMA wire in real-time. The integrated system includes a flexible needle prototype, a Raspberry Pi computer, a linear stage motor, an SMA wire actuator, a power supply, electromagnetic tracking system, and various communication supplies. The linear stage motor guides the needle into tissue. The power supply provides appropriate current to the SMA actuator. The tracking system measures tip movement for feedback, The Raspberry Pi is the central tool that receives the tip movement feedback and controls the linear stage motor and the SMA actuator via the power supply. The implemented algorithms required for communication and feedback control are also described. This paper demonstrates that the portable integrated system may be a viable solution for more effective procedures requiring surgical needles.

Vitamin D levels are associated with gross motor function in amyotrophic lateral sclerosis.

PubMed

Paganoni, Sabrina; Macklin, Eric A; Karam, Chafic; Yu, Hong; Gonterman, Fernando; Fetterman, K Ashley; Cudkowicz, Merit; Berry, James; Wills, Anne-Marie

2017-10-01

The objective of this study was to determine whether serum vitamin D [25(OH)D] levels are associated with disease progression in amyotrophic lateral sclerosis (ALS). 25(OH)D was measured in subjects enrolled in a multicenter study for validation of ALS biomarkers. Baseline 25(OH)D levels were correlated with baseline ALSFRS-R scores. Average 25(OH)D levels from baseline and month 6 visits (seasonally asynchronous) were used to predict subsequent rate of change in ALSFRS-R from month 6 to month 18. Most subjects had either insufficient or deficient 25(OH)D levels. Lower 25(OH)D was associated with lower ALSFRS-R gross motor scores, but not lower ALSFRS-R total scores at baseline. Levels of 25(OH)D were not predictive of disease progression over the next 12 months. 25(OH)D was associated with baseline gross motor ALSFRS-R scores but did not predict the rate of disease progression. Vitamin D levels may reflect poor mobility in patients with ALS. Muscle Nerve, 2017 Muscle Nerve 56: 726-731, 2017. © 2017 Wiley Periodicals, Inc.

42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

Code of Federal Regulations, 2014 CFR

2014-10-01

... RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84... multiple systems, whereby more than one user is supplied by one blower, will be approved, unless each hose...

42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

Code of Federal Regulations, 2013 CFR

2013-10-01

... RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84... multiple systems, whereby more than one user is supplied by one blower, will be approved, unless each hose...

42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

Code of Federal Regulations, 2010 CFR

2010-10-01

... RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84... multiple systems, whereby more than one user is supplied by one blower, will be approved, unless each hose...

42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

Code of Federal Regulations, 2012 CFR

2012-10-01

... RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84... multiple systems, whereby more than one user is supplied by one blower, will be approved, unless each hose...

42 CFR 84.142 - Air supply source; hand-operated or motor driven air blowers; Type A supplied-air respirators...

Code of Federal Regulations, 2011 CFR

2011-10-01

... RESEARCH AND RELATED ACTIVITIES APPROVAL OF RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84... multiple systems, whereby more than one user is supplied by one blower, will be approved, unless each hose...

Short Pulse Switches for Airborne High Power Supplies

DTIC Science & Technology

1973-10-01

IB 8. Rotary Mechanical Switch 20 9. Mechanical Switch, Essential Elements 24 10. Motor , Torsion Bar Electrodynamic Drive 28 11. Fast Acting...Gas Valve 31 12. Motor Test, Conductance, and Torque 33 13. Measured Motor Characteristics 34 14. Motor Structural Test Sample 36 15. Motor ...Fig. 42. Fig. 43. Fig. 44. Fig. 45. Fig. 46. Fig. 47. Fig. 48. Mechanical Switch 49 Arcing Contacts 51 Nonarcing Contacts 53 Motor

Photovoltaic-wind hybrid system for permanent magnet DC motor

NASA Astrophysics Data System (ADS)

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

2015-05-01

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sadowski, Greg

In one form, a logic circuit includes an asynchronous logic circuit, a synchronous logic circuit, and an interface circuit coupled between the asynchronous logic circuit and the synchronous logic circuit. The asynchronous logic circuit has a plurality of asynchronous outputs for providing a corresponding plurality of asynchronous signals. The synchronous logic circuit has a plurality of synchronous inputs corresponding to the plurality of asynchronous outputs, a stretch input for receiving a stretch signal, and a clock output for providing a clock signal. The synchronous logic circuit provides the clock signal as a periodic signal but prolongs a predetermined state ofmore » the clock signal while the stretch signal is active. The asynchronous interface detects whether metastability could occur when latching any of the plurality of the asynchronous outputs of the asynchronous logic circuit using said clock signal, and activates the stretch signal while the metastability could occur.« less

Flywheel induction motor-generator for magnet power supply in small fusion device.

PubMed

Hatakeyma, S; Yoshino, F; Tsutsui, H; Tsuji-Iio, S

2016-04-01

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10-100 ms).

Flywheel induction motor-generator for magnet power supply in small fusion device

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hatakeyma, S., E-mail: hatakeyama.shoichi@torus.nr.titech.ac.jp; Yoshino, F.; Tsutsui, H.

2016-04-15

A flywheel motor-generator (MG) for the toroidal field (TF) coils of a small fusion device was developed which utilizes a commercially available squirrel-cage induction motor. Advantages of the MG are comparably-long duration, quick power response, and easy implementation of power control compared with conventional capacitor-type power supply. A 55-kW MG was fabricated, and TF coils of a small fusion device were energized. The duration of the current flat-top was extended to 1 s which is much longer than those of conventional small devices (around 10–100 ms).

48 CFR 8.003 - Use of other Government supply sources.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES 8.003 Use of other Government supply sources... subpart 8.8); (c) Leased motor vehicles (see subpart 8.11); (d) Strategic and critical materials (e.g...

48 CFR 8.003 - Use of other Government supply sources.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES 8.003 Use of other Government supply sources... subpart 8.8); (c) Leased motor vehicles (see subpart 8.11); (d) Strategic and critical materials (e.g...

Motor Fault Diagnosis Based on Short-time Fourier Transform and Convolutional Neural Network

NASA Astrophysics Data System (ADS)

Wang, Li-Hua; Zhao, Xiao-Ping; Wu, Jia-Xin; Xie, Yang-Yang; Zhang, Yong-Hong

2017-11-01

With the rapid development of mechanical equipment, the mechanical health monitoring field has entered the era of big data. However, the method of manual feature extraction has the disadvantages of low efficiency and poor accuracy, when handling big data. In this study, the research object was the asynchronous motor in the drivetrain diagnostics simulator system. The vibration signals of different fault motors were collected. The raw signal was pretreated using short time Fourier transform (STFT) to obtain the corresponding time-frequency map. Then, the feature of the time-frequency map was adaptively extracted by using a convolutional neural network (CNN). The effects of the pretreatment method, and the hyper parameters of network diagnostic accuracy, were investigated experimentally. The experimental results showed that the influence of the preprocessing method is small, and that the batch-size is the main factor affecting accuracy and training efficiency. By investigating feature visualization, it was shown that, in the case of big data, the extracted CNN features can represent complex mapping relationships between signal and health status, and can also overcome the prior knowledge and engineering experience requirement for feature extraction, which is used by traditional diagnosis methods. This paper proposes a new method, based on STFT and CNN, which can complete motor fault diagnosis tasks more intelligently and accurately.

48 CFR 908.7101 - Motor vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Motor vehicles. 908.7101 Section 908.7101 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908.7101 Motor vehicles. ...

48 CFR 908.7101 - Motor vehicles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 5 2014-10-01 2014-10-01 false Motor vehicles. 908.7101 Section 908.7101 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908.7101 Motor vehicles. ...

48 CFR 908.7101 - Motor vehicles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 5 2012-10-01 2012-10-01 false Motor vehicles. 908.7101 Section 908.7101 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908.7101 Motor vehicles. ...

48 CFR 908.7101 - Motor vehicles.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 5 2013-10-01 2013-10-01 false Motor vehicles. 908.7101 Section 908.7101 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908.7101 Motor vehicles. ...

48 CFR 908.7101 - Motor vehicles.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 5 2011-10-01 2011-10-01 false Motor vehicles. 908.7101 Section 908.7101 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908.7101 Motor vehicles. ...

Nondestructive Evaluation of Metallized Tape Bonds Formed by Tape Automated Bonding (TAB)

DTIC Science & Technology

1989-04-01

powered by micro-positioning linear actuators. 3) Interchangeable sample-holding fixtures mounted upon top of slide assembly. 4) Coverslip gantry mounted...Controller Unit 1) Motor power supplies 2) Motor output servo driver amplifiers 3) "Macro-language" command Interpreter 4) Two-way cormunications with...adjustments are manual knobs giving approximately one degree of tilt adjustment per turn. The servo controller has self-contained power supplies for

46 CFR 129.320 - Generators and motors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Generators and motors. 129.320 Section 129.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems § 129.320 Generators and motors. (a) Each generator and...

46 CFR 129.320 - Generators and motors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Generators and motors. 129.320 Section 129.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems § 129.320 Generators and motors. (a) Each generator and...

46 CFR 129.320 - Generators and motors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Generators and motors. 129.320 Section 129.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS ELECTRICAL INSTALLATIONS Power Sources and Distribution Systems § 129.320 Generators and motors. (a) Each generator and...

Design and Experimental Verification of a 0.19 V 53 μW 65 nm CMOS Integrated Supply-Sensing Sensor With a Supply-Insensitive Temperature Sensor and an Inductive-Coupling Transmitter for a Self-Powered Bio-sensing System Using a Biofuel Cell.

PubMed

Kobayashi, Atsuki; Ikeda, Kei; Ogawa, Yudai; Kai, Hiroyuki; Nishizawa, Matsuhiko; Nakazato, Kazuo; Niitsu, Kiichi

2017-12-01

In this paper, we present a self-powered bio-sensing system with the capability of proximity inductive-coupling communication for supply sensing and temperature monitoring. The proposed bio-sensing system includes a biofuel cell as a power source and a sensing frontend that is associated with the CMOS integrated supply-sensing sensor. The sensor consists of a digital-based gate leakage timer, a supply-insensitive time-domain temperature sensor, and a current-driven inductive-coupling transmitter and achieves low-voltage operation. The timer converts the output voltage from a biofuel cell to frequency. The temperature sensor provides a pulse width modulation (PWM) output that is not dependent on the supply voltage, and the associated inductive-coupling transmitter enables proximity communication. A test chip was fabricated in 65 nm CMOS technology and consumed 53 μW with a supply voltage of 190 mV. The low-voltage-friendly design satisfied the performance targets of each integrated sensor without any trimming. The chips allowed us to successfully demonstrate proximity communication with an asynchronous receiver, and the measurement results show the potential for self-powered operation using biofuel cells. The analysis and experimental verification of the system confirmed their robustness.

Rhythm and interpersonal synchrony in early social development.

PubMed

Trainor, Laurel J; Cirelli, Laura

2015-03-01

Adults who engage in synchronous movement to music later report liking each other better, remembering more about each other, trusting each other more, and are more likely to cooperate with each other compared to adults who engage in asynchronous movements. Although poor motor coordination limits infants' ability to entrain to a musical beat, they perceive metrical structure in auditory rhythm patterns, their movements are affected by the tempo of music they hear, and if they are bounced by an adult to a rhythm pattern, the manner of this bouncing can affect their auditory interpretation of the meter of that pattern. In this paper, we review studies showing that by 14 months of age, infants who are bounced in synchrony with an adult subsequently show more altruistic behavior toward that adult in the form of handing back objects "accidentally" dropped by the adult compared to infants who are bounced asynchronously with the adult. Furthermore, increased helpfulness is directed at the synchronized bounce partner, but not at a neutral stranger. Interestingly, however, helpfulness does generalize to a "friend" of the synchronized bounce partner. In sum, synchronous movement between infants and adults has a powerful effect on infants' expression of directed prosocial behavior. © 2014 New York Academy of Sciences.

24 CFR 3280.811 - Calculations.

Code of Federal Regulations, 2010 CFR

2010-04-01

... motors and heater loads (exhaust fans, air conditioners, electric, gas, or oil heating). Omit smaller of air conditioning and heating except include blower motor if used as air conditioner evaporator motor. When an air conditioner is not installed and a 40-ampere power supply cord is provided, allow 15...

48 CFR 945.570-2 - Acquisition of motor vehicles.

Code of Federal Regulations, 2012 CFR

2012-10-01

... vehicles. 945.570-2 Section 945.570-2 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACT... Acquisition of motor vehicles. (a) The GSA Interagency Fleet Management System (GSA-IFMS) is the first source of supply for providing motor vehicles to contractors; however, contracting officer approval is...

Development of a PLC modem for data transmission over a PWM power supply

NASA Astrophysics Data System (ADS)

Batard, Christophe; Ginot, Nicolas; Mannah, Marc Anthony; Millet, Christophe; Poitiers, Frédéric

2014-04-01

In variable-speed electrical drive and online conditioning monitoring, a feedback loop is required in order to transmit the sensor information from the motor to the controller close to the inverter. Additional cabling is used for signalling. This extra cabling has a significant cost and data transmission may not be reliable. Thus, the use of power line communication (PLC) technology to transmit data in motor drive application is quite interesting. The use of a PLC modem dedicated to the home network in a three-phase inverter-fed motor power cable does not work. Therefore, specific coupling interfaces are developed to transmit data through a pulse-width modulated power supply. Laboratory tests have shown that the couplers are operating properly. They ensure reliable data transmission in a motor drive application.

ARC length control for plasma welding

NASA Technical Reports Server (NTRS)

Iceland, William F. (Inventor)

1988-01-01

A control system to be used with a plasma arc welding apparatus is disclosed. The plasma arc welding apparatus includes a plasma arc power supply, a contactor, and an electrode assembly for moving the electrode relative to a work piece. The electrode assembly is raised or lowered by a drive motor. The present apparatus includes a plasma arc adapter connected across the power supply to measure the voltage across the plasma arc. The plasma arc adapter forms a dc output signal input to a differential amplifier. A second input is defined by an adjustable resistor connected to a dc voltage supply to permit operator control. The differential amplifier forms an output difference signal provided to an adder circuit. The adder circuit then connects with a power amplifier which forms the driving signal for the motor. In addition, the motor connects to a tachometor which forms a feedback signal delivered to the adder to provide damping, therby avoiding servo loop overshoot.

Circuit Regulates Speed Of dc Motor

NASA Technical Reports Server (NTRS)

Weaver, Charles; Padden, Robin; Brown, Floyd A., Jr.

1990-01-01

Driving circuit regulates speed of small dc permanent-magnet motor in tape recorder. Two nested feedback loops maintain speed within 1 percent of constant value. Inner loop provides coarse regulation, while outer loop removes most of variation in speed that remains in the presence of regulation by the inner loop. Compares speed of motor with commanded speed and adjusts current supplied to motor accordingly.

Maintaining High Assurance in Asynchronous Messaging

DTIC Science & Technology

2015-10-24

Assurance in Asynchronous Messaging Kevin E. Foltz and William R. Simpson Abstract—Asynchronous messaging is the delivery of a message without... integrity , and confidentiality guarantees. End-to-end security for asynchronous messaging must be provided by the asynchronous messaging layer itself... continuing its processing. At the completion of message transmission, the sender does not know when or whether the receiver received it. The message

Study on Matching a 300 MVA Motor Generator with an Ohmic Heating Power Supply in HL-2M

NASA Astrophysics Data System (ADS)

Peng, Jianfei; Xuan, Weimin; Wang, Haibing; Li, Huajun; Wang, Yingqiao; Wang, Shujin

2013-03-01

A new 300 MVA/1350 MJ motor generator (MG) will be built to feed all of the poloidal field power supplies (PFPS) and auxiliary heating power supplies of the HL-2M tokamak. The MG has a vertical-shaft salient pole 6-phase synchronous generator and a coaxial 8500 kW induction motor. The Ohmic heating power supply (OHPS) consisting of 4-quadrant DC pulsed convertor is the one with the highest parameters among the PFPS. Therefore, the match between the generator and the OHPS is very important. The matching study with Matlab/Simulink is described in this paper. The simulation results show that the subtransient reactance of the generator is closely related to the inversion operation of the OHPS. By setting various subtransient reactance in the simulation generator model and considering the cost reduction, the optimized parameters are obtained as x″d = 0.405 p.u. at 100 Hz for the generator. The models built in the simulation can be used as an important tool for studying the dynamic characteristics and the control strategy of other HL-2M PFPSes.

Demand, Supply, and Price Outlook for Reformulated Motor Gasoline 1995

EIA Publications

1994-01-01

Provisions of the Clean Air Act Amendments of 1990 designed to reduce ground-level ozone will increase the demand for reformulated motor gasoline in a number of U.S. metropolitan areas. This article discusses the effects of the new regulations on the motor gasoline market and the refining industry.

Integrated-Circuit Controller For Brushless dc Motor

NASA Technical Reports Server (NTRS)

Le, Dong Tuan

1994-01-01

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

Virtual Hand Illusion Induced by Visuomotor Correlations

PubMed Central

Sanchez-Vives, Maria V.; Spanlang, Bernhard; Frisoli, Antonio; Bergamasco, Massimo; Slater, Mel

2010-01-01

Background Our body schema gives the subjective impression of being highly stable. However, a number of easily-evoked illusions illustrate its remarkable malleability. In the rubber-hand illusion, illusory ownership of a rubber-hand is evoked by synchronous visual and tactile stimulation on a visible rubber arm and on the hidden real arm. Ownership is concurrent with a proprioceptive illusion of displacement of the arm position towards the fake arm. We have previously shown that this illusion of ownership plus the proprioceptive displacement also occurs towards a virtual 3D projection of an arm when the appropriate synchronous visuotactile stimulation is provided. Our objective here was to explore whether these illusions (ownership and proprioceptive displacement) can be induced by only synchronous visuomotor stimulation, in the absence of tactile stimulation. Methodology/Principal Findings To achieve this we used a data-glove that uses sensors transmitting the positions of fingers to a virtually projected hand in the synchronous but not in the asynchronous condition. The illusion of ownership was measured by means of questionnaires. Questions related to ownership gave significantly larger values for the synchronous than for the asynchronous condition. Proprioceptive displacement provided an objective measure of the illusion and had a median value of 3.5 cm difference between the synchronous and asynchronous conditions. In addition, the correlation between the feeling of ownership of the virtual arm and the size of the drift was significant. Conclusions/Significance We conclude that synchrony between visual and proprioceptive information along with motor activity is able to induce an illusion of ownership over a virtual arm. This has implications regarding the brain mechanisms underlying body ownership as well as the use of virtual bodies in therapies and rehabilitation. PMID:20454463

Exploring the tolerability of spatiotemporally complex electrical stimulation paradigms.

PubMed

Nelson, Timothy S; Suhr, Courtney L; Lai, Alan; Halliday, Amy J; Freestone, Dean R; McLean, Karen J; Burkitt, Anthony N; Cook, Mark J

2011-10-01

A modified cortical stimulation model was used to investigate the effects of varying the synchronicity and periodicity of electrical stimuli delivered to multiple pairs of electrodes on seizure initiation. In this model, electrical stimulation of the motor cortex of rats, along four pairs of a microwire electrode array, results in an observable seizure with quantifiable electrographic duration and behavioural severity. Periodic stimuli had a constant inter-stimulus intervals across the two-second stimulus duration, whilst synchronous stimuli consisted of singular biphasic, bipolar pulses delivered to the four pairs of electrodes at precisely the same time for the entire two second stimulation period. In this way four combinations of stimulation were possible; periodic/synchronous (P/S), periodic/asynchronous (P/As), aperiodic/synchronous (Ap/S) and aperiodic/asynchronous (Ap/As). All stimulation types were designed with equal pulse width, current intensity and mean frequency of stimulation (60 Hz), standardizing net charge transfer. It was expected that the periodicity of the stimulus would be the primary determinant of seizure initiation and therefore severity and electrographic duration. However, the results showed that significant differences in both severity and duration only occurred when the synchronicity was altered. For periodic stimuli, synchronous delivery increased median seizure duration from 5 s to 13 s and increased median Racine severity from 1 to 3. In the aperiodic case, synchronous stimulus delivery increased median duration from 5.5 s to 11s and resulted in seizures of median severity 3 vs. 0 in the asynchronous case. These findings may have implications for the design of future neurostimulation waveform designs as higher numbers of electrodes and stimulator output channels become available in next generation implants. Copyright © 2011 Elsevier B.V. All rights reserved.

Design of automatic curtain controlled by wireless based on single chip 51 microcomputer

NASA Astrophysics Data System (ADS)

Han, Dafeng; Chen, Xiaoning

2017-08-01

In order to realize the wireless control of the domestic intelligent curtains, a set of wireless intelligent curtain control system based on 51 single chip microcomputer have been designed in this paper. The intelligent curtain can work in the manual mode, automatic mode and sleep mode and can be carried out by the button and mobile phone APP mode loop switch. Through the photosensitive resistance module and human pyroelectric infrared sensor to collect the indoor light value and the data whether there is the person in the room, and then after single chip processing, the motor drive module is controlled to realize the positive inversion of the asynchronous motor, the intelligent opening and closing of the curtain have been realized. The operation of the motor can be stopped under the action of the switch and the curtain opening and closing and timing switch can be controlled through the keys and mobile phone APP. The optical fiber intensity, working mode, curtain state and system time are displayed by LCD1602. The system has a high reliability and security under practical testing and with the popularity and development of smart home, the design has broad market prospects.

49 CFR 393.23 - Power supply for lamps.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Power supply for lamps. 393.23 Section 393.23 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.23 Power supply for...

49 CFR 393.23 - Power supply for lamps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Power supply for lamps. 393.23 Section 393.23 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL MOTOR CARRIER SAFETY... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.23 Power supply for...

Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering.

PubMed

Suraj; Tiwari, Purnendu; Ghosh, Subhojit; Sinha, Rakesh Kumar

2015-01-01

Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means clustering is found to outperform genetic algorithm (GA) and particle swarm optimization (PSO) based K-means clustering techniques in terms of both accuracy and execution time. The lesser execution time of hybrid GA-PSO technique makes it suitable for real time BCI application. Time frequency representation (TFR) techniques have been used to extract the feature of the signal under investigation. TFRs based features are extracted and relying on the concept of event related synchronization (ERD) and desynchronization (ERD) feature vector is formed.

Classification of Two Class Motor Imagery Tasks Using Hybrid GA-PSO Based K-Means Clustering

PubMed Central

Suraj; Tiwari, Purnendu; Ghosh, Subhojit; Sinha, Rakesh Kumar

2015-01-01

Transferring the brain computer interface (BCI) from laboratory condition to meet the real world application needs BCI to be applied asynchronously without any time constraint. High level of dynamism in the electroencephalogram (EEG) signal reasons us to look toward evolutionary algorithm (EA). Motivated by these two facts, in this work a hybrid GA-PSO based K-means clustering technique has been used to distinguish two class motor imagery (MI) tasks. The proposed hybrid GA-PSO based K-means clustering is found to outperform genetic algorithm (GA) and particle swarm optimization (PSO) based K-means clustering techniques in terms of both accuracy and execution time. The lesser execution time of hybrid GA-PSO technique makes it suitable for real time BCI application. Time frequency representation (TFR) techniques have been used to extract the feature of the signal under investigation. TFRs based features are extracted and relying on the concept of event related synchronization (ERD) and desynchronization (ERD) feature vector is formed. PMID:25972896

Flextensional ultrasonic piezoelectric micro-motor.

PubMed

Leinvuo, Joni T; Wilson, Stephen A; Whatmore, Roger W; Cain, Markys G

2006-12-01

This paper presents the experimental design, construction, and operational characteristics of a new type of standing wave piezoelectric ultrasonic micro-motor. The motor uses a composite stator, consisting of a metallic flex-tensional mode converter, or "cymbal", bonded to a 2-mm-square piezoelectric plate. The cymbal converts contour-mode vibrations of the plate into oscillations in the cymbal, perpendicular to the stator plane. These are further converted into rotational movement in a rotor pressed against the cymbal by means of an elastic-fin friction drive to produce the required rotary actuation. The motor operates on a single-phase electrical supply, and direct control of the output speed and torque can be achieved by adjusting the amplitude and frequency of the supply voltage. Noncontact optical techniques were used to assess the performance of the developed micro-motor. The operational characteristics were developed from the acceleration and deceleration characteristics. No-load output speed (11 rev s(-1)) and stall torque (27 nNm) were derived using high-speed imaging and image analysis. Maximum efficiency was 0.6%.

29 CFR 1926.406 - Specific purpose equipment and installations.

Code of Federal Regulations, 2013 CFR

2013-07-01

...—disconnecting means—(1) Motor-generator, AC transformer, and DC rectifier arc welders. A disconnecting means shall be provided in the supply circuit for each motor-generator arc welder, and for each AC transformer...

29 CFR 1926.406 - Specific purpose equipment and installations.

Code of Federal Regulations, 2012 CFR

2012-07-01

...—disconnecting means—(1) Motor-generator, AC transformer, and DC rectifier arc welders. A disconnecting means shall be provided in the supply circuit for each motor-generator arc welder, and for each AC transformer...

A Method to Determine Supply Voltage of Permanent Magnet Motor at Optimal Design Stage

NASA Astrophysics Data System (ADS)

Matustomo, Shinya; Noguchi, So; Yamashita, Hideo; Tanimoto, Shigeya

The permanent magnet motors (PM motors) are widely used in electrical machinery, such as air conditioner, refrigerator and so on. In recent years, from the point of view of energy saving, it is necessary to improve the efficiency of PM motor by optimization. However, in the efficiency optimization of PM motor, many design variables and many restrictions are required. In this paper, the efficiency optimization of PM motor with many design variables was performed by using the voltage driven finite element analysis with the rotating simulation of the motor and the genetic algorithm.

Acceptability of an Asynchronous Learning Forum on Mobile Devices

ERIC Educational Resources Information Center

Chang, Chih-Kai

2010-01-01

Mobile learning has recently become noteworthy because mobile devices have become popular. To construct an asynchronous learning forum on mobile devices is important because an asynchronous learning forum is always an essential part of networked asynchronous distance learning. However, the input interface in handheld learning devices, which is…

The Influence of Asynchronous Video Communication on Learner Social Presence: A Narrative Analysis of Four Cases

ERIC Educational Resources Information Center

Borup, Jered; West, Richard E.; Graham, Charles R.

2013-01-01

Online courses are increasingly using asynchronous video communication. However, little is known about how asynchronous video communication influences students' communication patterns. This study presents four narratives of students with varying characteristics who engaged in asynchronous video communication. The extrovert valued the efficiency of…

Robot gripper

NASA Technical Reports Server (NTRS)

Webb, Winston S. (Inventor)

1987-01-01

An electronic force-detecting robot gripper for gripping objects and attaching to an external robot arm is disclosed. The gripper comprises motor apparatus, gripper jaws, and electrical circuits for driving the gripper motor and sensing the amount of force applied by the jaws. The force applied by the jaws is proportional to a threshold value of the motor current. When the motor current exceeds the threshold value, the electrical circuits supply a feedback signal to the electrical control circuit which, in turn, stops the gripper motor.

49 CFR 393.23 - Power supply for lamps.

Code of Federal Regulations, 2014 CFR

2014-10-01

... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.23 Power supply for lamps. All required lamps must be powered by the electrical system of the motor vehicle with the...

Field Programmable Gate Array for Implementation of Redundant Advanced Digital Feedback Control

NASA Technical Reports Server (NTRS)

King, K. D.

2003-01-01

The goal of this effort was to develop a digital motor controller using field programmable gate arrays (FPGAs). This is a more rugged approach than a conventional microprocessor digital controller. FPGAs typically have higher radiation (rad) tolerance than both the microprocessor and memory required for a conventional digital controller. Furthermore, FPGAs can typically operate at higher speeds. (While speed is usually not an issue for motor controllers, it can be for other system controllers.) Other than motor power, only a 3.3-V digital power supply was used in the controller; no analog bias supplies were used. Since most of the circuit was implemented in the FPGA, no additional parts were needed other than the power transistors to drive the motor. The benefits that FPGAs provide over conventional designs-lower power and fewer parts-allow for smaller packaging and reduced weight and cost.

Dollar Summary of Federal Supply Classification and Service Category by Company, FY83, Part 1 (1005-5811).

DTIC Science & Technology

1983-01-01

E STATE TOTAL 590 LEAR S b1 . . . . • I . i I I I . DEPARTMENT OF DEFENSE PAGE 381 PRIME CONTRACTS OVER $25. 000 BY FEDERAL STOCK CLASSIFICATION...MOTOR VEHICLE MAINTENANCE EQUIPMENT 94 RONAN & KUNZL INC MICHIGAN ARMY MOTOR VEHICLE MAINTENANCE EQUIPMENT C9 RUGBY INDUSTRIES INC MINNESOTA ARMY MOTOR

Pharmacists' perception of synchronous versus asynchronous distance learning for continuing education programs.

PubMed

Buxton, Eric C

2014-02-12

To evaluate and compare pharmacists' satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars. An 8-lecture series of online presentations on the topic of new drug therapies was offered to pharmacists in synchronous and asynchronous webinar formats. Participants completed a 50-question online survey at the end of the program series to evaluate their perceptions of the distance learning experience. Eighty-two participants completed the survey instrument (41 participants from the live webinar series and 41 participants from the asynchronous webinar series.) Responses indicated that while both groups were satisfied with the program content, the asynchronous group showed greater satisfaction with many aspects of the learning environment. The synchronous and asynchronous webinar participants responded positively regarding the quality of the programming and the method of delivery, but asynchronous participants rated their experience more positively overall.

Pharmacists’ Perception of Synchronous Versus Asynchronous Distance Learning for Continuing Education Programs

PubMed Central

2014-01-01

Objective. To evaluate and compare pharmacists’ satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars. Methods. An 8-lecture series of online presentations on the topic of new drug therapies was offered to pharmacists in synchronous and asynchronous webinar formats. Participants completed a 50-question online survey at the end of the program series to evaluate their perceptions of the distance learning experience. Results. Eighty-two participants completed the survey instrument (41 participants from the live webinar series and 41 participants from the asynchronous webinar series.) Responses indicated that while both groups were satisfied with the program content, the asynchronous group showed greater satisfaction with many aspects of the learning environment. Conclusion. The synchronous and asynchronous webinar participants responded positively regarding the quality of the programming and the method of delivery, but asynchronous participants rated their experience more positively overall. PMID:24558276

Comparing the force ripple during asynchronous and conventional stimulation.

PubMed

Downey, Ryan J; Tate, Mark; Kawai, Hiroyuki; Dixon, Warren E

2014-10-01

Asynchronous stimulation has been shown to reduce fatigue during electrical stimulation; however, it may also exhibit a force ripple. We quantified the ripple during asynchronous and conventional single-channel transcutaneous stimulation across a range of stimulation frequencies. The ripple was measured during 5 asynchronous stimulation protocols, 2 conventional stimulation protocols, and 3 volitional contractions in 12 healthy individuals. Conventional 40 Hz and asynchronous 16 Hz stimulation were found to induce contractions that were as smooth as volitional contractions. Asynchronous 8, 10, and 12 Hz stimulation induced contractions with significant ripple. Lower stimulation frequencies can reduce fatigue; however, they may also lead to increased ripple. Future efforts should study the relationship between force ripple and the smoothness of the evoked movements in addition to the relationship between stimulation frequency and NMES-induced fatigue to elucidate an optimal stimulation frequency for asynchronous stimulation. © 2014 Wiley Periodicals, Inc.

Synchronous Office Hours in an Asynchronous Course: Making the Connection

ERIC Educational Resources Information Center

Gibbons-Kunka, Beatrice

2017-01-01

The notion of synchronous office hours in an asynchronous course seems counterintuitive. After all, one of the tenets of asynchronous education is to not require students to be online and participating at any time during the course. Having taught higher education online asynchronous courses for twenty years, the researcher experimented with online…

On the design of high-speed energy-efficient successive-approximation logic for asynchronous SAR ADCs

NASA Astrophysics Data System (ADS)

Yang, Jiaqi; Li, Ting; Yu, Mingyuan; Zhang, Shuangshuang; Lin, Fujiang; He, Lin

2017-08-01

This paper analyzes the power consumption and delay mechanisms of the successive-approximation (SA) logic of a typical asynchronous SAR ADC, and provides strategies to reduce both of them. Following these strategies, a unique direct-pass SA logic is proposed based on a full-swing once-triggered DFF and a self-locking tri-state gate. The unnecessary internal switching power of a typical TSPC DFF, which is commonly used in the SA logic, is avoided. The delay of the ready detector as well as the sequencer is removed from the critical path. A prototype SAR ADC based on the proposed SA logic is fabricated in 130 nm CMOS. It achieves a peak SNDR of 56.3 dB at 1.2 V supply and 65 MS/s sampling rate, and has a total power consumption of 555 μW, while the digital part consumes only 203 μW. Project supported by the National Natural Science Foundation of China (Nos. 61204033, 61331015), the Fundamental Research Funds for the Central Universities (No. WK2100230015), and the Funds of Science and Technology on Analog Integrated Circuit Laboratory (No. 9140C090111150C09041).

Studying the development of asynchronous rolling of the rotor over the stator with the turbine unit protection systems having different response times

NASA Astrophysics Data System (ADS)

Shatokhin, V. F.

2014-07-01

The possibility to stabilize the developing asynchronous rolling of the rotor over the stator under the conditions of power unit protections coming in action with different response times is considered. Asynchronous rolling of the rotor over the stator may develop when the rotating rotor comes in contact with the stator at high amplitudes of vibration caused by an abrupt loss of rotor balancing, by forced or self-excited vibration of the rotor, and by other factors. The danger of asynchronous rolling is connected with almost instantaneous development of self-excited vibration of the rotor when it comes in contact with the stator and with the rotor vibration amplitudes and forces of interaction between the rotor and stator dangerous for the turbine unit integrity. It is assumed that the turbine unit protection systems come in action after the arrival of signal of exceeding the permissible vibration level and produce commands to disconnect the generator from the grid, and to stop the supply of working fluid into the flow path, due to which an accelerating torque ceases to act on the turbine unit shaft. The protection system response speed is determined by a certain time t = ABtime that is taken for its components to come in action from the commencement of the event (application of the signal) to closure of the stop valves. The time curves of the main rolling parameters as functions of the ABtime value are presented. It is shown that the response time of existing protection systems is not sufficient for efficiently damping the rolling phenomenon, although the use of an electrical protection system (with the response time equal to 0.40-0.45 s) may have a positive effect on stabilizing the vibration amplitudes to a certain extent during the rolling and on smoothing its dangerous consequences. The consequences of rotor rolling over the stator can be efficiently mitigated by increasing the energy losses in the rotor-stator system (especially in the stator) and by fulfilling the recommendations of the machinery unit catastrophe prevention system.

Coupling between myosin head conformation and the thick filament backbone structure.

PubMed

Hu, Zhongjun; Taylor, Dianne W; Edwards, Robert J; Taylor, Kenneth A

2017-12-01

The recent high-resolution structure of the thick filament from Lethocerus asynchronous flight muscle shows aspects of thick filament structure never before revealed that may shed some light on how striated muscles function. The phenomenon of stretch activation underlies the function of asynchronous flight muscle. It is most highly developed in flight muscle, but is also observed in other striated muscles such as cardiac muscle. Although stretch activation is likely to be complex, involving more than a single structural aspect of striated muscle, the thick filament itself, would be a prime site for regulatory function because it must bear all of the tension produced by both its associated myosin motors and any externally applied force. Here we show the first structural evidence that the arrangement of myosin heads within the interacting heads motif is coupled to the structure of the thick filament backbone. We find that a change in helical angle of 0.16° disorders the blocked head preferentially within the Lethocerus interacting heads motif. This observation suggests a mechanism for how tension affects the dynamics of the myosin heads leading to a detailed hypothesis for stretch activation and shortening deactivation, in which the blocked head preferentially binds the thin filament followed by the free head when force production occurs. Copyright © 2017 Elsevier Inc. All rights reserved.

Hysteresis, phase transitions, and dangerous transients in electrical power distribution systems.

PubMed

Duclut, Charlie; Backhaus, Scott; Chertkov, Michael

2013-06-01

The majority of dynamical studies in power systems focus on the high-voltage transmission grids where models consider large generators interacting with crude aggregations of individual small loads. However, new phenomena have been observed indicating that the spatial distribution of collective, nonlinear contribution of these small loads in the low-voltage distribution grid is crucial to the outcome of these dynamical transients. To elucidate the phenomenon, we study the dynamics of voltage and power flows in a spatially extended distribution feeder (circuit) connecting many asynchronous induction motors and discover that this relatively simple 1+1 (space+time) dimensional system exhibits a plethora of nontrivial spatiotemporal effects, some of which may be dangerous for power system stability. Long-range motor-motor interactions mediated by circuit voltage and electrical power flows result in coexistence and segregation of spatially extended phases defined by individual motor states, a "normal" state where the motors' mechanical (rotation) frequency is slightly smaller than the nominal frequency of the basic ac flows and a "stalled" state where the mechanical frequency is small. Transitions between the two states can be initiated by a perturbation of the voltage or base frequency at the head of the distribution feeder. Such behavior is typical of first-order phase transitions in physics, and this 1+1 dimensional model shows many other properties of a first-order phase transition with the spatial distribution of the motors' mechanical frequency playing the role of the order parameter. In particular, we observe (a) propagation of the phase-transition front with the constant speed (in very long feeders) and (b) hysteresis in transitions between the normal and stalled (or partially stalled) phases.

49 CFR 393.23 - Power supply for lamps.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Power supply for lamps. 393.23 Section 393.23... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.23 Power supply for lamps. All required lamps must be powered by the electrical system of the motor vehicle with the...

49 CFR 393.23 - Power supply for lamps.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 5 2012-10-01 2012-10-01 false Power supply for lamps. 393.23 Section 393.23... NECESSARY FOR SAFE OPERATION Lamps, Reflective Devices, and Electrical Wiring § 393.23 Power supply for lamps. All required lamps must be powered by the electrical system of the motor vehicle with the...

An epigenetic state associated with areas of gene duplication

PubMed Central

Gimelbrant, Alexander A.; Chess, Andrew

2006-01-01

Asynchronous DNA replication is an epigenetically determined feature found in all cases of monoallelic expression, including genomic imprinting, X-inactivation, and random monoallelic expression of autosomal genes such as immunoglobulins and olfactory receptor genes. Most genes of the latter class were identified in experiments focused on genes functioning in the chemosensory and immune systems. We performed an unbiased survey of asynchronous replication in the mouse genome, excluding known asynchronously replicated genes. Fully 10% (eight of 80) of the genes tested exhibited asynchronous replication. A common feature of the newly identified asynchronously replicated areas is their proximity to areas of tandem gene duplication. Testing of other clustered areas supported the idea that such regions are enriched with asynchronously replicated genes. PMID:16687731

The Study of Residual Voltage of Induction Motor and the Influence of Various Parameters on the Residual Voltage

NASA Astrophysics Data System (ADS)

Zhang, Shuping; Zhao, Chen; Tan, Weipu

2017-05-01

The majority important load of industrial area is mainly composed of induction motor, it is more common that induction motor becomes sluggishness and even tripping due to the lose of power supply or other malfunction in the practical work. In this paper, space vector method is used to establish a reduced order model of induction motor, and then study the changes of motor electromagnetic after losing electricity. Based on motion equations of the rotor and magnetic flux conservation principle, it uses mathematical methods to deduce the expression of rotor current, rotor flux, the stator flux and the residual voltage of stator side. In addition, relying on thermal power plants, it uses the actual data of power plants, takes DIgsilent software to simulate the residual voltage of motor after losing electricity. analyses the influence on the residual voltage with the changes of the moment of inertia, load ratio, initial size of slip and the load characteristic of induction motor. By analysis of these, it has a more detailed understanding about the changes of residual voltage in practical application, in additional, it is more beneficial to put into standby power supply safely and effectively, moreover, reduce the influence of the input process to the whole system.

Motor innervation of the trapezius muscle: Intraoperative motor conduction study during neck dissection.

PubMed

Kim, Jin Hwan; Choi, Kyu Young; Lee, Kyu Ho; Lee, Dong Jin; Park, Bum Jung; Rho, Young-Soo

2014-01-01

To evaluate the motor input from the spinal accessory nerve (SAN) and the branches of the cervical plexus in an intraoperative motor nerve conduction study measuring motor action potentials by direct stimulation of the exposed nerve during neck dissection. The entire length of the SAN and the contributions from the upper cervical plexus were preserved. Compound muscle action potentials were measured for each part of the trapezius muscle on stimulation of the SAN, C2, C3, and C4 nerves. With stimulation of the spinal nerve, evoked responses were obtained from all 24 patients in the descending, transverse, and ascending trapezius muscle. C2 contributions were noted in 2 out of 24 patients; however, no patient revealed responses in all three parts of the muscle. C3 contributions were seen in 11 out of 24 patients, supplying all three parts of the muscle in 8 patients, and C4 contributions were noted in 20 out of 24 patients, supplying all three parts of the muscle in 16 of them. The SAN provided the most consistent motor input to the trapezius muscle. The C2, C3, and C4 nerves also provided motor input to the trapezius muscle; however, they were either inconsistently present or, when present, irregularly innervated the three parts of the trapezius muscle.

Improving Control of Two Motor Controllers

NASA Technical Reports Server (NTRS)

Toland, Ronald W.

2004-01-01

A computer program controls motors that drive translation stages in a metrology system that consists of a pair of two-axis cathetometers. This program is specific to Compumotor Gemini (or equivalent) motors and the Compumotor 6K-series (or equivalent) motor controller. Relative to the software supplied with the controller, this program affords more capabilities and is easier to use. Written as a Virtual Instrument in the LabVIEW software system, the program presents an imitation control panel that the user can manipulate by use of a keyboard and mouse. There are three modes of operation: command, movement, and joystick. In command mode, single commands are sent to the controller for troubleshooting. In movement mode, distance, speed, and/or acceleration commands are sent to the controller. Position readouts from the motors and from position encoders on the translation stages are displayed in marked fields. At any time, the position readouts can be recorded in a file named by the user. In joystick mode, the program yields control of the motors to a joystick. The program sends commands to, and receives data from, the controller via a serial cable connection, using the serial-communication portion of the software supplied with the controller.

A Phenomenological Synapse Model for Asynchronous Neurotransmitter Release

PubMed Central

Wang, Tao; Yin, Luping; Zou, Xiaolong; Shu, Yousheng; Rasch, Malte J.; Wu, Si

2016-01-01

Neurons communicate with each other via synapses. Action potentials cause release of neurotransmitters at the axon terminal. Typically, this neurotransmitter release is tightly time-locked to the arrival of an action potential and is thus called synchronous release. However, neurotransmitter release is stochastic and the rate of release of small quanta of neurotransmitters can be considerably elevated even long after the ceasing of spiking activity, leading to asynchronous release of neurotransmitters. Such asynchronous release varies for tissue and neuron types and has been shown recently to be pronounced in fast-spiking neurons. Notably, it was found that asynchronous release is enhanced in human epileptic tissue implicating a possibly important role in generating abnormal neural activity. Current neural network models for simulating and studying neural activity virtually only consider synchronous release and ignore asynchronous transmitter release. Here, we develop a phenomenological model for asynchronous neurotransmitter release, which, on one hand, captures the fundamental features of the asynchronous release process, and, on the other hand, is simple enough to be incorporated in large-size network simulations. Our proposed model is based on the well-known equations for short-term dynamical synaptic interactions and includes an additional stochastic term for modeling asynchronous release. We use experimental data obtained from inhibitory fast-spiking synapses of human epileptic tissue to fit the model parameters, and demonstrate that our model reproduces the characteristics of realistic asynchronous transmitter release. PMID:26834617

75 FR 82389 - Notice of a Project Waiver of Section 1605 (Buy American Requirement) of the American Recovery...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-30

... (HP) vertical hollow shaft electric motor, for use in a water supply well. The 15 HP vertical hollow... percent. The District's water system improvement project includes the development of a new water supply... use in a water supply well. Therefore, EPA Region 6 concludes that the District meets the...

Detection of movement intention from single-trial movement-related cortical potentials

NASA Astrophysics Data System (ADS)

Niazi, Imran Khan; Jiang, Ning; Tiberghien, Olivier; Feldbæk Nielsen, Jørgen; Dremstrup, Kim; Farina, Dario

2011-10-01

Detection of movement intention from neural signals combined with assistive technologies may be used for effective neurofeedback in rehabilitation. In order to promote plasticity, a causal relation between intended actions (detected for example from the EEG) and the corresponding feedback should be established. This requires reliable detection of motor intentions. In this study, we propose a method to detect movements from EEG with limited latency. In a self-paced asynchronous BCI paradigm, the initial negative phase of the movement-related cortical potentials (MRCPs), extracted from multi-channel scalp EEG was used to detect motor execution/imagination in healthy subjects and stroke patients. For MRCP detection, it was demonstrated that a new optimized spatial filtering technique led to better accuracy than a large Laplacian spatial filter and common spatial pattern. With the optimized spatial filter, the true positive rate (TPR) for detection of movement execution in healthy subjects (n = 15) was 82.5 ± 7.8%, with latency of -66.6 ± 121 ms. Although TPR decreased with motor imagination in healthy subject (n = 10, 64.5 ± 5.33%) and with attempted movements in stroke patients (n = 5, 55.01 ± 12.01%), the results are promising for the application of this approach to provide patient-driven real-time neurofeedback.

Controlling a Four-Quadrant Brushless Three-Phase dc Motor

NASA Technical Reports Server (NTRS)

Nola, F. J.

1986-01-01

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

Designing Asynchronous Communication Tools for Optimization of Patient-Clinician Coordination

PubMed Central

Eschler, Jordan; Liu, Leslie S.; Vizer, Lisa M.; McClure, Jennifer B.; Lozano, Paula; Pratt, Wanda; Ralston, James D.

2015-01-01

Asynchronous communication outside the clinical setting has both enriched and complicated patient-clinician interactions. Many patients can now interact with a patient portal 24 hours a day, asking questions of their clinicians via secure message, checking lab results, ordering medication refills, or making appointments. However, the mode of communication (asynchronous) and the nature of the interaction (lacking tone or body language) strip valuable information from each side of patient-clinician asynchronous communication. Using interviews with 34 individuals who actively manage a chronic illness of their own, or for a child or partner, we elicited narratives about patients’ experiences and expectations for using asynchronous communication to address medical issues with their clinicians. Based on these perspectives, we present opportunities for designing asynchronous communication tools to better facilitate understanding of and coordination around care activities between patients and clinicians. PMID:26958188

Asynchronous Video Streaming vs. Synchronous Videoconferencing for Teaching a Pharmacogenetic Pharmacotherapy Course

PubMed Central

2007-01-01

Objectives To compare students' performance and course evaluations for a pharmacogenetic pharmacotherapy course taught by synchronous videoconferencing method via the Internet and for the same course taught via asynchronous video streaming via the Internet. Methods In spring 2005, a pharmacogenetic therapy course was taught to 73 students located on Amarillo, Lubbock, and Dallas campuses using synchronous videoconferencing, and in spring 2006, to 78 students located on the same 3 campuses using asynchronous video streaming. A course evaluation was administered to each group at the end of the courses. Results Students in the asynchronous setting had final course grades of 89% ± 7% compared to the mean final course grade of 87% ± 7% in the synchronous group (p = 0.05). Regardless of which technology was used, average course grades did not differ significantly among the 3 campus sites. Significantly more of the students in the asynchronous setting agreed (57%) with the statement that they could read the lecture notes and absorb the content on their own without attending the class than students in the synchronous class (23%; chi-square test; p < 0.001). Conclusions Students in both asynchronous and synchronous settings performed well. However, students taught using asynchronous videotaped lectures had lower satisfaction with the method of content delivery, and preferred live interactive sessions or a mix of interactive sessions and asynchronous videos over delivery of content using the synchronous or asynchronous method alone. PMID:17429516

Redundant speed control for brushless Hall effect motor

NASA Technical Reports Server (NTRS)

Nola, F. J. (Inventor)

1973-01-01

A speed control system for a brushless Hall effect device equipped direct current (D.C.) motor is described. Separate windings of the motor are powered by separate speed responsive power sources. A change in speed, upward or downward, because of the failure of a component of one of the power sources results in a corrective signal being generated in the other power source to supply an appropriate power level and polarity to one winding to cause the motor to be corrected in speed.

New York City Metropolitan Area Retail Motor Gasoline Supply Report

EIA Publications

2012-01-01

Final report of the Energy Information Administration's (EIA) emergency survey, which was started on Friday, November 2, 2012, to monitor the vehicle fuel supply conditions in the New York City metropolitan area on a temporary basis after Hurricane Sandy.

Marginal Pipeline Costs of Enlisted Personnel.

DTIC Science & Technology

1979-12-03

printing, cleaning supplies , organizational equipment for train- ing support, barracks furnishings, motor pools and various other items. (USMC: MC... cleaning , supplies , and related items. 11-26 C. ARMY MISSION/SUPPORT COSTS The Army accepted 124,000 active NPS accessions in FY1978. These

Features of Synchronous Electronically Commutated Motors in Servomotor Operation Modes

NASA Astrophysics Data System (ADS)

Dirba, J.; Lavrinovicha, L.; Dobriyan, R.

2017-04-01

The authors consider the features and operation specifics of the synchronous permanent magnet motors and the synchronous reluctance motors with electronic commutation in servomotor operation modes. Calculation results show that mechanical and control characteristics of studied motors are close to a linear shape. The studied motor control is proposed to implement similar to phase control of induction servomotor; it means that angle θ (angle between vectors of the supply voltage and non-load electromotive force) or angle ɛ (angle between rotor direct axis and armature magnetomotive force axis) is changed. The analysis results show that synchronous electronically commutated motors could be used as servomotors.

A projection of motor fuel tax revenue and analysis of alternative revenue sources in Georgia.

DOT National Transportation Integrated Search

2012-05-01

Motor fuel tax revenue currently supplies the majority of funding for : transportation agencies at the state and federal level. Georgia uses excise and sales taxes : to generate revenue for the Georgia Department of Transportation (GDOT). Inflation a...

Building asynchronous geospatial processing workflows with web services

NASA Astrophysics Data System (ADS)

Zhao, Peisheng; Di, Liping; Yu, Genong

2012-02-01

Geoscience research and applications often involve a geospatial processing workflow. This workflow includes a sequence of operations that use a variety of tools to collect, translate, and analyze distributed heterogeneous geospatial data. Asynchronous mechanisms, by which clients initiate a request and then resume their processing without waiting for a response, are very useful for complicated workflows that take a long time to run. Geospatial contents and capabilities are increasingly becoming available online as interoperable Web services. This online availability significantly enhances the ability to use Web service chains to build distributed geospatial processing workflows. This paper focuses on how to orchestrate Web services for implementing asynchronous geospatial processing workflows. The theoretical bases for asynchronous Web services and workflows, including asynchrony patterns and message transmission, are examined to explore different asynchronous approaches to and architecture of workflow code for the support of asynchronous behavior. A sample geospatial processing workflow, issued by the Open Geospatial Consortium (OGC) Web Service, Phase 6 (OWS-6), is provided to illustrate the implementation of asynchronous geospatial processing workflows and the challenges in using Web Services Business Process Execution Language (WS-BPEL) to develop them.

About the Power Generation Confirmation of the Induction Motor and the Influence on the Islanding Detection Device

NASA Astrophysics Data System (ADS)

Igarashi, Hironobu; Sato, Takashi; Miyamoto, Kazunori; Kurokawa, Kousuke

The photovoltaic generation system must have protection device and islanding detection devices to connect with utility line of the electric power company. It is regulated in the technological requirement guideline and the electric equipment technology standard that the country provides. The islanding detection device detected purpose install for blackout due to the accident occurrence of the earth fault and the short-circuit in the utility line. When the islanding detection device detects the power blackout, it is necessary to stop the photovoltaic generation system immediately. If the photovoltaic generation system is not stopped immediately, electricity comes to charge the utility power line very at risk. We had already known that the islanding detection device can't detect the islanding phenomenon, if is there the induction motor in the loads. Authors decided to investigate the influence that the induction motors gave to the islanding detection device. The result was the load condition that the induction motors changed generator the voltage is restraining. Moreover, it was clarified that the time of the islanding was long compared with the load condition of not changing into the state of the generator. The value changes into the reactance of the induction motors according to the frequency change after the supply of electric power line stops. The frequency after the supply of electric power line stops changes for the unbalance the reactive power by the effect of the power rate constancy control with PLL of the power conditioner. However, the induction motors is also to the changing frequency, makes amends for the amount of reactive power, and the change in the frequency after the supply of electric power line stops as a result is controlled. When the frequency changed after the supply of electric power line stopped, it was clarified of the action on the direction where it made amends from the change of the constant for the amount of an invalid electric power, and the possession of the characteristic in which the continuance of the individual operation was promoted.

GEODE An electrical energy supply with high availability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mertz, J.L.; Gerard, M.J.; Girard, J.

1983-10-01

Project GEODE describes an electrical energy supply characterized by its very high availability. It is to be used in the PTT (French Telephone Company) telephone exchanges and is targeted for an unavailability of better than 10/sup -6/. In order to achieve this performance Merlin Gerin has adopted: a double bus bar architecture, remote controlled electrical equipment, a motor-generator set specifically designed for this project, and computer assisted surveillance. The authors present the overall reliability calculations for this project along with that for energy sources. The E.d.F (French Utility Company) network and the Motor-Generators.

A Novel Permanent Magnetic Angular Acceleration Sensor

PubMed Central

Zhao, Hao; Feng, Hao

2015-01-01

Angular acceleration is an important parameter for status monitoring and fault diagnosis of rotary machinery. Therefore, we developed a novel permanent magnetic angular acceleration sensor, which is without rotation angle limitations and could directly measure the instantaneous angular acceleration of the rotating system. The sensor rotor only needs to be coaxially connected with the rotating system, which enables convenient sensor installation. For the cup structure of the sensor rotor, it has a relatively small rotational inertia. Due to the unique mechanical structure of the sensor, the output signal of the sensor can be directed without a slip ring, which avoids signal weakening effect. In this paper, the operating principle of the sensor is described, and simulated using finite element method. The sensitivity of the sensor is calibrated by torsional pendulum and angle sensor, yielding an experimental result of about 0.88 mV/(rad·s−2). Finally, the angular acceleration of the actual rotating system has been tested, using both a single-phase asynchronous motor and a step motor. Experimental result confirms the operating principle of the sensor and indicates that the sensor has good practicability. PMID:26151217

48 CFR 908.7101-4 - Replacement of motor vehicles.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Replacement of motor vehicles. 908.7101-4 Section 908.7101-4 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Acquisition of Special Items 908...

41 CFR 109-26.501 - Purchase of new motor vehicles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Purchase of new motor vehicles. 109-26.501 Section 109-26.501 Public Contracts and Property Management Federal Property Management Regulations System (Continued) DEPARTMENT OF ENERGY PROPERTY MANAGEMENT REGULATIONS SUPPLY AND...

48 CFR 945.570-1 - Acquisition of motor vehicles.

Code of Federal Regulations, 2014 CFR

2014-10-01

... vehicles. 945.570-1 Section 945.570-1 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACT... vehicles. (a) GSA Interagency Fleet Management System (GSA-IFMS) is the first source of supply for providing motor vehicles to contractors; however, contracting officer approval is required for contractors...

Modelling and control algorithms of the cross conveyors line with multiengine variable speed drives

NASA Astrophysics Data System (ADS)

Cheremushkina, M. S.; Baburin, S. V.

2017-02-01

The paper deals with the actual problem of developing the control algorithm that meets the technical requirements of the mine belt conveyors, and enables energy and resource savings taking into account a random sort of traffic. The most effective method of solution of these tasks is the construction of control systems with the use of variable speed drives for asynchronous motors. The authors designed the mathematical model of the system ‘variable speed multiengine drive - conveyor - control system of conveyors’ that takes into account the dynamic processes occurring in the elements of the transport system, provides an assessment of the energy efficiency of application the developed algorithms, which allows one to reduce the dynamic overload in the belt to 15-20%.

Avoiding Complications in Abdominal Wall Surgery: A Mathematical Model to Predict the Course of the Motor Innervation of the Rectus Abdominis.

PubMed

Tessone, Ariel; Nava, Maurizio; Blondeel, Phillip; Spano, Andrea

2016-02-01

Ever since its introduction, the transverse rectus abdominis myocutaneous flap has become the mainstay of autologous breast reconstruction. However, concerns regarding donor site morbidity due to the breach of abdominal wall musculature integrity soon followed. Muscle-sparing techniques, eventually eliminating the muscle from the flap all-together with the deep inferior epigastric artery perforator flap, did not eliminate the problem of abdominal wall weakness. This led to the conclusion that motor innervation might be at fault. Studies have shown that even in the presence of an intact rectus abdominis muscle, and an intact anterior rectus sheath, denervation of the rectus abdominis muscle results in significant abdominal wall weakness leading to superior and inferior abdominal bulges, and abdominal herniation. Our aim was to establish a mathematical model to predict the location of the motor innervation to the rectus abdominis muscle, and thus provide surgeons with a tool that will allow them to reduce abdominal morbidity during deep inferior epigastric artery perforator and free muscle-sparing transverse rectus abdominis myocutaneous surgery. We dissected 42 cadaveric hemiabdomens and mapped the course of the thoracolumbar nerves. We then standardized and analyzed our findings and presented them as a relative map which can be adjusted to body type and dimensions. Our dissections show that the motor innervation is closely related to the lateral vascular supply. Thus, when possible, we support the preferred utilization of the medial vascular supply, and the preservation of the lateral supply and motor innervation.

Are the interarytenoid muscles supplied by branches of both the recurrent and superior laryngeal nerves?

PubMed

Pascual-Font, Arán; Cubillos, Luis; Vázquez, Teresa; McHanwell, Steve; Sañudo, José R; Maranillo, Eva

2016-05-01

It has been generally accepted that the branches of the internal branch of the superior laryngeal nerve to the interarytenoid muscle are exclusively sensory. However, some experimental studies have suggested that these branches may contain motor axons, and therefore that the interarytenoid muscle is supplied by both the superior and recurrent laryngeal nerves. The aim of this work was to determine whether motor axons to the interarytenoid muscles are present in both laryngeal nerves. Basic research. Twelve human internal branches of the superior laryngeal nerve were dissected, and its branches to the interarytenoid muscle were removed and processed for choline-acetyltransferase immunohistochemistry, a method not used previously in studying the nerve fiber composition of the laryngeal nerves. The internal branch of the superior laryngeal nerve divided into two to five branches to the interarytenoid muscle. All branches contained motor axons, with the proportion of motor axons varying from 6% to 31%. The present study confirms that the internal branch of the superior laryngeal nerve provides a motor innervation to the interarytenoid muscles. N/A. Laryngoscope, 126:1117-1122, 2016. © 2015 The American Laryngological, Rhinological and Otological Society, Inc.

41 CFR 101-26.501-9 - Centralized motor vehicle leasing program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 41 Public Contracts and Property Management 2 2010-07-01 2010-07-01 true Centralized motor vehicle leasing program. 101-26.501-9 Section 101-26.501-9 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS SUPPLY AND PROCUREMENT 26...

Adult-Supplied Structure and Children's Activity Levels.

ERIC Educational Resources Information Center

Carpenter, C. J.; And Others

This study investigated the relationship between preschool children's participation in play activities structured by adults and the level of motor activity children exhibited while in those activities, to test the hypothesis that children's motor activity levels vary according to the level of structure imposed on activities by adults. Subjects…

Synchronization of Hierarchical Time-Varying Neural Networks Based on Asynchronous and Intermittent Sampled-Data Control.

PubMed

Xiong, Wenjun; Patel, Ragini; Cao, Jinde; Zheng, Wei Xing

In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.

Digital Synchronizer without Metastability

NASA Technical Reports Server (NTRS)

Simle, Robert M.; Cavazos, Jose A.

2009-01-01

A proposed design for a digital synchronizing circuit would eliminate metastability that plagues flip-flop circuits in digital input/output interfaces. This metastability is associated with sampling, by use of flip-flops, of an external signal that is asynchronous with a clock signal that drives the flip-flops: it is a temporary flip-flop failure that can occur when a rising or falling edge of an asynchronous signal occurs during the setup and/or hold time of a flip-flop. The proposed design calls for (1) use of a clock frequency greater than the frequency of the asynchronous signal, (2) use of flip-flop asynchronous preset or clear signals for the asynchronous input, (3) use of a clock asynchronous recovery delay with pulse width discriminator, and (4) tying the data inputs to constant logic levels to obtain (5) two half-rate synchronous partial signals - one for the falling and one for the rising edge. Inasmuch as the flip-flop data inputs would be permanently tied to constant logic levels, setup and hold times would not be violated. The half-rate partial signals would be recombined to construct a signal that would replicate the original asynchronous signal at its original rate but would be synchronous with the clock signal.

The Effects of Asynchronous Visual Delays on Simulator Flight Performance and the Development of Simulator Sickness Symptomatology

DTIC Science & Technology

1986-12-26

NAVAL TRAINING SYSTEMS CENTER ORLANDO. FLORIDA IT FILE COPY THE EFFECTS OF ASYNCHRONOUS VISUAL DELAYS ON SIMULATOR FLIGHT PERFORMANCE AND THE...ASYNCHRONOUS VISUAL. DELAYS ON SI.WLATOR FLIGHT PERF OMANCE AND THE DEVELOPMENT OF SIMLATOR SICKNESS SYMPTOMATOLOGY K. C. Uliano, E. Y. Lambert, R. S. Kennedy...ACCESSION NO. N63733N SP-01 0785-7P6 I. 4780 11. TITLE (Include Security Classification) The Effects of Asynchronous Visual Delays on Simulator Flight

Modeling and Analysis of Mixed Synchronous/Asynchronous Systems

NASA Technical Reports Server (NTRS)

Driscoll, Kevin R.; Madl. Gabor; Hall, Brendan

2012-01-01

Practical safety-critical distributed systems must integrate safety critical and non-critical data in a common platform. Safety critical systems almost always consist of isochronous components that have synchronous or asynchronous interface with other components. Many of these systems also support a mix of synchronous and asynchronous interfaces. This report presents a study on the modeling and analysis of asynchronous, synchronous, and mixed synchronous/asynchronous systems. We build on the SAE Architecture Analysis and Design Language (AADL) to capture architectures for analysis. We present preliminary work targeted to capture mixed low- and high-criticality data, as well as real-time properties in a common Model of Computation (MoC). An abstract, but representative, test specimen system was created as the system to be modeled.

A novel comparator featured with input data characteristic

NASA Astrophysics Data System (ADS)

Jiang, Xiaobo; Ye, Desheng; Xu, Xiangmin; Zheng, Shuai

2016-03-01

Two types of low-power asynchronous comparators featured with input data statistical characteristic are proposed in this article. The asynchronous ripple comparator stops comparing at the first unequal bit but delivers the result to the least significant bit. The pre-stop asynchronous comparator can completely stop comparing and obtain results immediately. The proposed and contrastive comparators were implemented in SMIC 0.18 μm process with different bit widths. Simulation shows that the proposed pre-stop asynchronous comparator features the lowest power consumption, shortest average propagation delay and highest area efficiency among the comparators. Data path of low-density parity check decoder using the proposed pre-stop asynchronous comparators are most power efficient compared with other data paths with synthesised, clock gating and bitwise competition logic comparators.

Intermodulation components in the transmitter RF output due to high voltage power supply ripple

NASA Technical Reports Server (NTRS)

Finnegan, E. J.

1977-01-01

The economic feasibility of eliminating the 400-Hz motor-generator sets used to provide power to the high-voltage power supplies of the 20-kW transmitters and replace them with a 60-Hz high-voltage power supply was investigated. The efficiency of a power supply that runs from the 60-Hz line directly would pay for itself in about seven years and could be designed so that the transmitter would meet all the incidental phase and amplitude modulation specifications.

Interactional Coherence in Asynchronous Learning Networks: A Rhetorical Approach

ERIC Educational Resources Information Center

Potter, Andrew

2008-01-01

Numerous studies have affirmed the value of asynchronous online communication as a learning resource. Several investigations, however, have indicated that discussions in asynchronous environments are often neither interactive nor coherent. The research reported sought to develop an enhanced understanding of interactional coherence, argumentation,…

Labeled Postings for Asynchronous Interaction

ERIC Educational Resources Information Center

ChanLin, Lih-Juan; Chen, Yong-Ting; Chan, Kung-Chi

2009-01-01

The Internet promotes computer-mediated communications, and so asynchronous learning network systems permit more flexibility in time, space, and interaction than synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online…

An Asynchronous Augmentation to Traditional Course Delivery.

ERIC Educational Resources Information Center

Wolverton, Marvin L.; Wolverton, Mimi

Asynchronous augmentation facilitates distributed learning, which relies heavily on technology and self-learning. This paper reports the results of delivering a real estate principles course using an asynchronous course delivery format. It highlights one of many ways to enhance learning using technology, and it provides information concerning how…

A Taxonomy of Learning through Asynchronous Discussion

ERIC Educational Resources Information Center

Knowlton, Dave S.

2005-01-01

This article presents a five-tiered taxonomy that describes the nature of participation in, and learning through, asynchronous discussion. The taxonomy is framed by a constructivist view of asynchronous discussion. The five tiers of the taxonomy include the following: (a) passive participation, (b) developmental participation, (c) generative…

Designing Asynchronous Online Discussion Environments: Recent Progress and Possible Future Directions

ERIC Educational Resources Information Center

Gao, Fei; Zhang, Tianyi; Franklin, Teresa

2013-01-01

Asynchronous online discussion environments are important platforms to support learning. Research suggests, however, threaded forums, one of the most popular asynchronous discussion environments, do not often foster productive online discussions naturally. This paper explores how certain properties of threaded forums have affected or constrained…

Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

ERIC Educational Resources Information Center

Smith, S. C.; Al-Assadi, W. K.; Di, J.

2010-01-01

As demand increases for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design…

Detection of stator winding faults in induction motors using three-phase current monitoring.

PubMed

Sharifi, Rasool; Ebrahimi, Mohammad

2011-01-01

The objective of this paper is to propose a new method for the detection of inter-turn short circuits in the stator windings of induction motors. In the previous reported methods, the supply voltage unbalance was the major difficulty, and this was solved mostly based on the sequence component impedance or current which are difficult to implement. Some other methods essentially are included in the offline methods. The proposed method is based on the motor current signature analysis and utilizes three phase current spectra to overcome the mentioned problem. Simulation results indicate that under healthy conditions, the rotor slot harmonics have the same magnitude in three phase currents, while under even 1 turn (0.3%) short circuit condition they differ from each other. Although the magnitude of these harmonics depends on the level of unbalanced voltage, they have the same magnitude in three phases in these conditions. Experiments performed under various load, fault, and supply voltage conditions validate the simulation results and demonstrate the effectiveness of the proposed technique. It is shown that the detection of resistive slight short circuits, without sensitivity to supply voltage unbalance is possible. Copyright © 2010 ISA. Published by Elsevier Ltd. All rights reserved.

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2013 CFR

2013-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2012 CFR

2012-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2010 CFR

2010-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2011 CFR

2011-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

46 CFR 111.97-5 - Electric and hydraulic power supply.

Code of Federal Regulations, 2014 CFR

2014-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Electric Power-Operated Watertight Door Systems § 111.97-5 Electric and hydraulic power supply. (a) Each electric motor-driven door operating system must have the same.... (f) The source of power for each hydraulically operated watertight door system using an independent...

Actively Engaging Students in Asynchronous Online Classes. IDEA Paper #64

ERIC Educational Resources Information Center

Riggs, Shannon A.; Linder, Kathryn E.

2016-01-01

Active learning activities and pedagogical strategies can look different in online learning environments, particularly in asynchronous courses when students are not interacting with the instructor, or with each other, in real time. This paper suggests a three-pronged approach for conceptualizing active learning in the online asynchronous class:…

Exploring Asynchronous and Synchronous Tool Use in Online Courses

ERIC Educational Resources Information Center

Oztok, Murat; Zingaro, Daniel; Brett, Clare; Hewitt, Jim

2013-01-01

While the independent contributions of synchronous and asynchronous interaction in online learning are clear, comparatively less is known about the pedagogical consequences of using both modes in the same environment. In this study, we examine relationships between students' use of asynchronous discussion forums and synchronous private messages…

Teaching Presence and Communication Timeliness in Asynchronous Online Courses

ERIC Educational Resources Information Center

Skramstad, Erik; Schlosser, Charles; Orellana, Anymir

2012-01-01

This study examined student perceptions of teaching presence and communication timeliness in asynchronous online courses. Garrison, Anderson, and Archer's (2000) community of inquiry model provided the framework for the survey research methodology used. Participants were 59 student volunteers taking 1 or more asynchronous online graduate courses.…

Two Studies Examining Argumentation in Asynchronous Computer Mediated Communication

ERIC Educational Resources Information Center

Joiner, Richard; Jones, Sarah; Doherty, John

2008-01-01

Asynchronous computer mediated communication (CMC) would seem to be an ideal medium for supporting development in student argumentation. This paper investigates this assumption through two studies. The first study compared asynchronous CMC with face-to-face discussions. The transactional and strategic level of the argumentation (i.e. measures of…

Using Television Sitcoms to Facilitate Asynchronous Discussions in the Online Communication Course

ERIC Educational Resources Information Center

Tolman, Elizabeth; Asbury, Bryan

2012-01-01

Asynchronous discussions are a useful instructional resource in the online communication course. In discussion groups students have the opportunity to actively participate and interact with students and the instructor. Asynchronous communication allows for flexibility because "participants can interact with significant amounts of time between…

Asynchronous Discussion Board Facilitation and Rubric Use in a Blended Learning Environment

ERIC Educational Resources Information Center

Giacumo, Lisa

2012-01-01

The purpose of this study was to investigate the effects of instructor response prompts and rubrics on students' performance in an asynchronous discussion-board assignment, their learning achievement on an objective-type posttest, and their reported satisfaction levels. Researchers who have studied asynchronous computer-mediated student…

Designing Asynchronous, Text-Based Computer Conferences: Ten Research-Based Suggestions

ERIC Educational Resources Information Center

Choitz, Paul; Lee, Doris

2006-01-01

Asynchronous computer conferencing refers to the use of computer software and a network enabling participants to post messages that allow discourse to continue even though interactions may be extended over days and weeks. Asynchronous conferences are time-independent, adapting to multiple time zones and learner schedules. Such activities as…

Asynchronous Learning Forums for Business Acculturation

ERIC Educational Resources Information Center

Pence, Christine Cope; Wulf, Catharina

2009-01-01

The use of IT as a facilitator for student collaboration in higher business education has grown rapidly since 2000. Asynchronous discussion forums are used abundantly for collaborative training purposes and for teaching students business-relevant tools for their future careers. This article presents an analysis of the asynchronous discussion forum…

Comparing face-to-face, synchronous, and asynchronous learning: postgraduate dental resident preferences.

PubMed

Kunin, Marc; Julliard, Kell N; Rodriguez, Tobias E

2014-06-01

The Department of Dental Medicine of Lutheran Medical Center has developed an asynchronous online curriculum consisting of prerecorded PowerPoint presentations with audio explanations. The focus of this study was to evaluate if the new asynchronous format satisfied the educational needs of the residents compared to traditional lecture (face-to-face) and synchronous (distance learning) formats. Lectures were delivered to 219 dental residents employing face-to-face and synchronous formats, as well as the new asynchronous format; 169 (77 percent) participated in the study. Outcomes were assessed with pretests, posttests, and individual lecture surveys. Results found the residents preferred face-to-face and asynchronous formats to the synchronous format in terms of effectiveness and clarity of presentations. This preference was directly related to the residents' perception of how well the technology worked in each format. The residents also rated the quality of student-instructor and student-student interactions in the synchronous and asynchronous formats significantly higher after taking the lecture series than they did before taking it. However, they rated the face-to-face format as significantly more conducive to student-instructor and student-student interaction. While the study found technology had a major impact on the efficacy of this curricular model, the results suggest that the asynchronous format can be an effective way to teach a postgraduate course.

Asynchronous glimpsing of speech: Spread of masking and task set-size

PubMed Central

Ozmeral, Erol J.; Buss, Emily; Hall, Joseph W.

2012-01-01

Howard-Jones and Rosen [(1993). J. Acoust. Soc. Am. 93, 2915–2922] investigated the ability to integrate glimpses of speech that are separated in time and frequency using a “checkerboard” masker, with asynchronous amplitude modulation (AM) across frequency. Asynchronous glimpsing was demonstrated only for spectrally wide frequency bands. It is possible that the reduced evidence of spectro-temporal integration with narrower bands was due to spread of masking at the periphery. The present study tested this hypothesis with a dichotic condition, in which the even- and odd-numbered bands of the target speech and asynchronous AM masker were presented to opposite ears, minimizing the deleterious effects of masking spread. For closed-set consonant recognition, thresholds were 5.1–8.5 dB better for dichotic than for monotic asynchronous AM conditions. Results were similar for closed-set word recognition, but for open-set word recognition the benefit of dichotic presentation was more modest and level dependent, consistent with the effects of spread of masking being level dependent. There was greater evidence of asynchronous glimpsing in the open-set than closed-set tasks. Presenting stimuli dichotically supported asynchronous glimpsing with narrower frequency bands than previously shown, though the magnitude of glimpsing was reduced for narrower bandwidths even in some dichotic conditions. PMID:22894234

Asynchronous vs didactic education: it's too early to throw in the towel on tradition.

PubMed

Jordan, Jaime; Jalali, Azadeh; Clarke, Samuel; Dyne, Pamela; Spector, Tahlia; Coates, Wendy

2013-08-08

Asynchronous, computer based instruction is cost effective, allows self-directed pacing and review, and addresses preferences of millennial learners. Current research suggests there is no significant difference in learning compared to traditional classroom instruction. Data are limited for novice learners in emergency medicine. The objective of this study was to compare asynchronous, computer-based instruction with traditional didactics for senior medical students during a week-long intensive course in acute care. We hypothesized both modalities would be equivalent. This was a prospective observational quasi-experimental study of 4th year medical students who were novice learners with minimal prior exposure to curricular elements. We assessed baseline knowledge with an objective pre-test. The curriculum was delivered in either traditional lecture format (shock, acute abdomen, dyspnea, field trauma) or via asynchronous, computer-based modules (chest pain, EKG interpretation, pain management, trauma). An interactive review covering all topics was followed by a post-test. Knowledge retention was measured after 10 weeks. Pre and post-test items were written by a panel of medical educators and validated with a reference group of learners. Mean scores were analyzed using dependent t-test and attitudes were assessed by a 5-point Likert scale. 44 of 48 students completed the protocol. Students initially acquired more knowledge from didactic education as demonstrated by mean gain scores (didactic: 28.39% ± 18.06; asynchronous 9.93% ± 23.22). Mean difference between didactic and asynchronous = 18.45% with 95% CI [10.40 to 26.50]; p = 0.0001. Retention testing demonstrated similar knowledge attrition: mean gain scores -14.94% (didactic); -17.61% (asynchronous), which was not significantly different: 2.68% ± 20.85, 95% CI [-3.66 to 9.02], p = 0.399. The attitudinal survey revealed that 60.4% of students believed the asynchronous modules were educational and 95.8% enjoyed the flexibility of the method. 39.6% of students preferred asynchronous education for required didactics; 37.5% were neutral; 23% preferred traditional lectures. Asynchronous, computer-based instruction was not equivalent to traditional didactics for novice learners of acute care topics. Interactive, standard didactic education was valuable. Retention rates were similar between instructional methods. Students had mixed attitudes toward asynchronous learning but enjoyed the flexibility. We urge caution in trading in traditional didactic lectures in favor of asynchronous education for novice learners in acute care.

26 CFR 1.164-3 - Definitions and special rules.

Code of Federal Regulations, 2011 CFR

2011-04-01

... sold, and the term “medical supplies” includes drugs, medicines, and medical devices. (4) Except in the... qualify as ad valorem. For example, a motor vehicle tax based on weight, model year, and horsepower, or..., clothing, medical supplies, and motor vehicles, or any of them, shall not be taken into account in...

36 CFR 293.6 - Commercial enterprises, roads, motor vehicles, motorized equipment, motorboats, aircraft...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 36 Parks, Forests, and Public Property 2 2011-07-01 2011-07-01 false Commercial enterprises, roads..., structures, and cutting of trees. 293.6 Section 293.6 Parks, Forests, and Public Property FOREST SERVICE... forms of mechanical transport; no landing of aircraft; no dropping of materials, supplies, or persons...

76 FR 4726 - General Motors Company Formerly Known as General Motors Corporation Technical Center Including On...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-26

... and General Physics Corporation Excluding Workers of the Global Purchasing and Supply Chain Division... plants. The company reports that workers leased from General Physics Corporation were employed on-site at..., Technical Center. The Department has determined that on-site workers from General Physics Corporation were...

Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex.

PubMed

Lu, Yao; Truccolo, Wilson; Wagner, Fabien B; Vargas-Irwin, Carlos E; Ozden, Ilker; Zimmermann, Jonas B; May, Travis; Agha, Naubahar S; Wang, Jing; Nurmikko, Arto V

2015-06-01

Transient gamma-band (40-80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions.

Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex

PubMed Central

Lu, Yao; Truccolo, Wilson; Wagner, Fabien B.; Vargas-Irwin, Carlos E.; Ozden, Ilker; Zimmermann, Jonas B.; May, Travis; Agha, Naubahar S.; Wang, Jing

2015-01-01

Transient gamma-band (40–80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions. PMID:25761956

Straight and chopped dc performance data for a Prestolite MTC-4001 motor and a general electric EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Performance data on the Prestolite MTC-4001 series wound dc motor and General Electric EV-1 Chopper Controller is supplied for the electric vehicle manufacturer. Data are provided for both straight and chopped dc input to the motor, at 2 motor temperature levels. Testing was done at 6 voltage increments to the motor, and 2 voltage increments to the controller. Data results are presented in both tabular and graphical forms. Tabular information includes motor voltage and current input data, motor speed and torque output data, power data and temperature data. Graphical information includes torque-speed, motor power output-speed, torque-current, and efficiency-speed plots under the various operating conditions. The data resulting from this testing show the speed-torque plots to have the most variance with operating temperature. The maximum motor efficiency is between 76% and 82%, regardless of temperature or mode of operation.

Motor/generator and electronic control considerations for energy storage flywheels

NASA Technical Reports Server (NTRS)

Nola, F. J.

1984-01-01

A spacecraft electric power supply system is described. Requirements of the system are to accelerate a momentum wheel to a fixed maximum speed when solar energy is available and to maintain a constant voltage on the spacecraft bus under varying loads when solar energy is not available. Candidate motor types, pulse width modulated current control systems, and efficiency considerations are discussed. In addition, the Lunar Roving Vehicle motors are described along with their respective efficiencies.

Motor efficiency: compare apples to apples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keinz, J.R.

1982-08-01

The efficiency differences between electric motors are now a significant cost consideration for many companies, but evaluating motor efficiency is not as straightforward as it should be. The buyer must look beyond the manufacturer's designated efficiency, which is too generalized, and the results of independent tests, which vary because of the difficulty in establishing standard conditions. Manufacturers may be following established testing procedures, but not labeling in accordance with the standards. Manufacturers should also supply efficiency versus load-curve data. (DCK)

A propulsion and steering control system for the Mars rover

NASA Technical Reports Server (NTRS)

Turner, J. M.

1980-01-01

The design of a propulsion and steering control system for the Rensselaer Polytechnic Institute prototype autonomous Mars roving vehicle is presented. The vehicle is propelled and steered by four independent electric motors. The control system must regulate the speeds of the motors so they work in unison during turns and on irregular terrain. An analysis of the motor coordination problem on irregular terrain, where each motor must supply a different torque at a different speed is presented. A procedure was developed to match the output of each motor to the varying load. A design for the control system is given. The controller uses a microprocessor which interprets speed and steering commands from an off-board computer, and produces the appropriate drive voltages for the motors.

Simulative and experimental investigation on stator winding turn and unbalanced supply voltage fault diagnosis in induction motors using Artificial Neural Networks.

PubMed

Lashkari, Negin; Poshtan, Javad; Azgomi, Hamid Fekri

2015-11-01

The three-phase shift between line current and phase voltage of induction motors can be used as an efficient fault indicator to detect and locate inter-turn stator short-circuit (ITSC) fault. However, unbalanced supply voltage is one of the contributing factors that inevitably affect stator currents and therefore the three-phase shift. Thus, it is necessary to propose a method that is able to identify whether the unbalance of three currents is caused by ITSC or supply voltage fault. This paper presents a feedforward multilayer-perceptron Neural Network (NN) trained by back propagation, based on monitoring negative sequence voltage and the three-phase shift. The data which are required for training and test NN are generated using simulated model of stator. The experimental results are presented to verify the superior accuracy of the proposed method. Copyright © 2015. Published by Elsevier Ltd.

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

NASA Technical Reports Server (NTRS)

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.

Variable current speed controller for eddy current motors

DOEpatents

Gerth, H.L.; Bailey, J.M.; Casstevens, J.M.; Dixon, J.H.; Griffith, B.O.; Igou, R.E.

1982-03-12

A speed control system for eddy current motors is provided in which the current to the motor from a constant frequency power source is varied by comparing the actual motor speed signal with a setpoint speed signal to control the motor speed according to the selected setpoint speed. A three-phase variable voltage autotransformer is provided for controlling the voltage from a three-phase power supply. A corresponding plurality of current control resistors is provided in series with each phase of the autotransformer output connected to inputs of a three-phase motor. Each resistor is connected in parallel with a set of normally closed contacts of plurality of relays which are operated by control logic. A logic circuit compares the selected speed with the actual motor speed obtained from a digital tachometer monitoring the motor spindle speed and operated the relays to add or substract resistance equally in each phase of the motor input to vary the motor current to control the motor at the selected speed.

Accuracy of iron loss estimation in induction motors by using different iron loss models

NASA Astrophysics Data System (ADS)

Štumberger, B.; Hamler, A.; Goričan, V.; Jesenik, M.; Trlep, M.

2004-05-01

The paper presents iron loss estimation in a three-phase induction motor by using different iron loss models for the posterior iron loss calculation. The iron losses were determined by using modeled properties of used electrical steel and calculated distribution of magnetic induction B(t) in all parts of the motor by using 2D finite element software for a complete cycle of field variation. The comparison between estimated and measured core losses for a 4kW induction motor at no-load in dependency on supply voltage is given.

Fostering Critical Reflection in a Computer-Based, Asynchronously Delivered Diversity Training Course

ERIC Educational Resources Information Center

Givhan, Shawn T.

2013-01-01

This dissertation study chronicles the creation of a computer-based, asynchronously delivered diversity training course for a state agency. The course format enabled efficient delivery of a mandatory curriculum to the Massachusetts Department of State Police workforce. However, the asynchronous format posed a challenge to achieving the learning…

Anonymity and Motivation in Asynchronous Discussions and L2 Vocabulary Learning

ERIC Educational Resources Information Center

Polat, Nihat; Mancilla, Rae; Mahalingappa, Laura

2013-01-01

This study investigates L2 attainment in asynchronous online environments, specifically possible relationships among anonymity, L2 motivation, participation in discussions, quality of L2 production, and success in L2 vocabulary learning. It examines, in asynchronous discussions, (a) if participation and (b) motivation contribute to L2 vocabulary…

Exploring the Effect of Scripted Roles on Cognitive Presence in Asynchronous Online Discussions

ERIC Educational Resources Information Center

Olesova, Larisa; Slavin, Margaret; Lim, Jieun

2016-01-01

The purpose of this study was to identify the effect of scripted roles on students' level of cognitive presence in asynchronous online threaded discussions. A quantitative content analysis was used to investigate: (1) what level of cognitive presence is achieved by students' assigned roles in asynchronous online discussions; (2) differences…

A Multi-Perspective Investigation into Learners' Interaction in Asynchronous Computer-Mediated Communication (CMC)

ERIC Educational Resources Information Center

Çardak, Çigdem Suzan

2016-01-01

This article focusses on graduate level students' interactions during asynchronous CMC activities of an online course about the teaching profession in Turkey. The instructor of the course designed and facilitated a semester-long asynchronous CMC on forum discussions, and investigated the interaction of learners in multiple perspectives: learners'…

The Negotiation Model in Asynchronous Computer-Mediated Communication (CMC): Negotiation in Task-Based Email Exchanges

ERIC Educational Resources Information Center

Kitade, Keiko

2006-01-01

Based on recent studies, computer-mediated communication (CMC) has been considered a tool to aid in language learning on account of its distinctive interactional features. However, most studies have referred to "synchronous" CMC and neglected to investigate how "asynchronous" CMC contributes to language learning. Asynchronous CMC possesses…

Integrating the Intangibles into Asynchronous Online Instruction: Strategies for Improving Interaction and Social Presence

ERIC Educational Resources Information Center

McGuire, Beverley Foulks

2016-01-01

This paper considers how instructors of asynchronous online courses in the Humanities might integrate intangibles associated with face-to-face instruction into their online environments. It presents a case study of asynchronous online instruction in a philosophy and religion department at a midsize public university in the southeastern United…

Postgraduate Students' Knowledge Construction during Asynchronous Computer Conferences in a Blended Learning Environment: A Malaysian Experience

ERIC Educational Resources Information Center

Kian-Sam, Hong; Lee, Julia Ai Cheng

2008-01-01

Blended learning, using e-learning tools to supplement existing on campus learning, often incorporates asynchronous computer conferencing as a means of augmenting knowledge construction among students. This case study reports findings about levels of knowledge construction amongst adult postgraduate students in six asynchronous computer…

Asynchronous Learning Sources in a High-Tech Organization

ERIC Educational Resources Information Center

Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

2009-01-01

Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

Asynchronous reference frame agreement in a quantum network

NASA Astrophysics Data System (ADS)

Islam, Tanvirul; Wehner, Stephanie

2016-03-01

An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

Pediatric emergency medicine asynchronous e-learning: a multicenter randomized controlled Solomon four-group study.

PubMed

Chang, Todd P; Pham, Phung K; Sobolewski, Brad; Doughty, Cara B; Jamal, Nazreen; Kwan, Karen Y; Little, Kim; Brenkert, Timothy E; Mathison, David J

2014-08-01

Asynchronous e-learning allows for targeted teaching, particularly advantageous when bedside and didactic education is insufficient. An asynchronous e-learning curriculum has not been studied across multiple centers in the context of a clinical rotation. We hypothesize that an asynchronous e-learning curriculum during the pediatric emergency medicine (EM) rotation improves medical knowledge among residents and students across multiple participating centers. Trainees on pediatric EM rotations at four large pediatric centers from 2012 to 2013 were randomized in a Solomon four-group design. The experimental arms received an asynchronous e-learning curriculum consisting of nine Web-based, interactive, peer-reviewed Flash/HTML5 modules. Postrotation testing and in-training examination (ITE) scores quantified improvements in knowledge. A 2 × 2 analysis of covariance (ANCOVA) tested interaction and main effects, and Pearson's correlation tested associations between module usage, scores, and ITE scores. A total of 256 of 458 participants completed all study elements; 104 had access to asynchronous e-learning modules, and 152 were controls who used the current education standards. No pretest sensitization was found (p = 0.75). Use of asynchronous e-learning modules was associated with an improvement in posttest scores (p < 0.001), from a mean score of 18.45 (95% confidence interval [CI] = 17.92 to 18.98) to 21.30 (95% CI = 20.69 to 21.91), a large effect (partial η(2) = 0.19). Posttest scores correlated with ITE scores (r(2) = 0.14, p < 0.001) among pediatric residents. Asynchronous e-learning is an effective educational tool to improve knowledge in a clinical rotation. Web-based asynchronous e-learning is a promising modality to standardize education among multiple institutions with common curricula, particularly in clinical rotations where scheduling difficulties, seasonality, and variable experiences limit in-hospital learning. © 2014 by the Society for Academic Emergency Medicine.

Reducing The Risk Of Fires In Conveyor Transport

NASA Astrophysics Data System (ADS)

Cheremushkina, M. S.; Poddubniy, D. A.

2017-01-01

The paper deals with the actual problem of increasing the safety of operation of belt conveyors in mines. Was developed the control algorithm that meets the technical requirements of the mine belt conveyors, reduces the risk of fires of conveyors belt, and enables energy and resource savings taking into account random sort of traffic. The most effective method of decision such tasks is the construction of control systems with the use of variable speed drives for asynchronous motors. Was designed the mathematical model of the system "variable speed multiengine drive - conveyor - control system of conveyors", that takes into account the dynamic processes occurring in the elements of the transport system, provides an assessment of the energy efficiency of application the developed algorithms, which allows to reduce the dynamic overload in the belt to (15-20)%.

Broadband changes in the cortical surface potential track activation of functionally diverse neuronal populations

PubMed Central

Miller, Kai J; Honey, Christopher J; Hermes, Dora; Rao, Rajesh PN; denNijs, Marcel; Ojemann, Jeffrey G

2013-01-01

We illustrate a general principal of electrical potential measurements from the surface of the cerebral cortex, by revisiting and reanalyzing experimental work from the visual, language and motor systems. A naïve decomposition technique of electrocorticographic power spectral measurements reveals that broadband spectral changes reliably track task engagement. These broadband changes are shown to be a generic correlate of local cortical function across a variety of brain areas and behavioral tasks. Furthermore, they fit a power-law form that is consistent with simple models of the dendritic integration of asynchronous local population firing. Because broadband spectral changes covary with diverse perceptual and behavioral states on the timescale of 20–50ms, they provide a powerful and widely applicable experimental tool. PMID:24018305

Modeling and Analysis of Asynchronous Systems Using SAL and Hybrid SAL

NASA Technical Reports Server (NTRS)

Tiwari, Ashish; Dutertre, Bruno

2013-01-01

We present formal models and results of formal analysis of two different asynchronous systems. We first examine a mid-value select module that merges the signals coming from three different sensors that are each asynchronously sampling the same input signal. We then consider the phase locking protocol proposed by Daly, Hopkins, and McKenna. This protocol is designed to keep a set of non-faulty (asynchronous) clocks phase locked even in the presence of Byzantine-faulty clocks on the network. All models and verifications have been developed using the SAL model checking tools and the Hybrid SAL abstractor.

Asynchronous discrete control of continuous processes

NASA Astrophysics Data System (ADS)

Kaliski, M. E.; Johnson, T. L.

1984-07-01

The research during this second contract year continued to deal with the development of sound theoretical models for asynchronous systems. Two criteria served to shape the research pursued: the first, that the developed models extend and generalize previously developed research for synchronous discrete control; the second, that the models explicitly address the question of how to incorporate system transition times into themselves. The following sections of this report concisely delineate this year's work. Our original proposal for this research identified four general tasks of investigation: (1.1) Analysis of Qualitative Properties of Asynchronous Hybrid Systems; (1.2) Acceptance and Control for Asynchronous Hybrid Systems.

77 FR 70481 - Fasco, A Division of Regal Beloit Corporation, Including On-Site Leased Workers From Penmac...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-11-26

... distribution of electric motors, as well as engineering, customer service and information technology (IT... portion of the supply of engineering services (or like or directly competitive services) to a foreign..., Missouri, who were engaged in employment related to the supply of warehousing, distribution, engineering...

Motor torque compensation of an induction electric motor by adjusting a slip command during periods of supposed change in motor temperature

DOEpatents

Kelledes, William L.; St. John, Don K.

1992-01-01

The present invention maintains constant torque in an inverter driven AC induction motor during variations in rotor temperature. It is known that the torque output of a given AC induction motor is dependent upon rotor temperature. At rotor temperatures higher than the nominal operating condition the rotor impedance increases, reducing the rotor current and motor torque. In a similar fashion, the rotor impedance is reduced resulting in increased rotor current and motor torque when the rotor temperature is lower than the nominal operating condition. The present invention monitors the bus current from the DC supply to the inverter and adjusts the slip frequency of the inverter drive to maintain a constant motor torque. This adjustment is based upon whether predetermined conditions implying increased rotor temperature or decreased rotor temperature exist for longer that a predetermined interval of time.

Combining Live Video and Audio Broadcasting, Synchronous Chat, and Asynchronous Open Forum Discussions in Distance Education

ERIC Educational Resources Information Center

Teng, Tian-Lih; Taveras, Marypat

2004-01-01

This article outlines the evolution of a unique distance education program that began as a hybrid--combining face-to-face instruction with asynchronous online teaching--and evolved to become an innovative combination of synchronous education using live streaming video, audio, and chat over the Internet, blended with asynchronous online discussions…

Utilizing Spectrum Efficiently (USE)

DTIC Science & Technology

2011-02-28

18 4.8 Space-Time Coded Asynchronous DS - CDMA with Decentralized MAI Suppression: Performance and...numerical results. 4.8 Space-Time Coded Asynchronous DS - CDMA with Decentralized MAI Suppression: Performance and Spectral Efficiency In [60] multiple...supported at a given signal-to-interference ratio in asynchronous direct-sequence code-division multiple-access ( DS - CDMA ) sys- tems was examined. It was

The Development, Validity, and Reliability of Communication Satisfaction in an Online Asynchronous Discussion Scale

ERIC Educational Resources Information Center

Hung, Min-Ling; Chou, Chien

2014-01-01

The purpose of this study was to identify dimensions of students' communication satisfaction in an asynchronous discussion forum. An asynchronous discussion may be defined as text-based human-to-human communication via computer networks that provides a platform for the participants to interact with one another to exchange ideas, insights, and…

Web-based Cases in Teaching and Learning - the Quality of Discussions and a Stage of Perspective Taking in Asynchronous Communication.

ERIC Educational Resources Information Center

Jarvela, Sanna; Hakkinen, Paivi

2002-01-01

Examines the quality of asynchronous interaction in Web-based conferencing among preservice teachers. The study combines asynchronous conferencing with peer and mentor collaboration to electronically apprentice student learning. Results point out different levels of Web-based discussion: higher-level, progressive, and lower-level discussion. A…

Design of a three-phase, 15-kilovolt-ampere static inverter for motor-starting a Brayton space power system

NASA Technical Reports Server (NTRS)

Frye, R. J.; Birchenough, A. G.

1971-01-01

The design of a three-phase, 400-Hz, 15-kVA static inverter for motor-starting the 2- to 15-kWe Brayton electrical space power system is described. The inverter operates from a nominal 56-V dc source to provide a 28-V, rms, quasi-square-wave output. The inverter is capable of supplying a 200-A peak current. Integrated circuitry is used to generate the three-phase, 400-Hz reference signals. Performance data for a drive stage that improves switching speed and provides efficient operation over a range of output current and drive supply voltage are presented. A transformerless, transistor output stage is used.

A Linear Electromagnetic Piston Pump

NASA Astrophysics Data System (ADS)

Hogan, Paul H.

Advancements in mobile hydraulics for human-scale applications have increased demand for a compact hydraulic power supply. Conventional designs couple a rotating electric motor to a hydraulic pump, which increases the package volume and requires several energy conversions. This thesis investigates the use of a free piston as the moving element in a linear motor to eliminate multiple energy conversions and decrease the overall package volume. A coupled model used a quasi-static magnetic equivalent circuit to calculate the motor inductance and the electromagnetic force acting on the piston. The force was an input to a time domain model to evaluate the mechanical and pressure dynamics. The magnetic circuit model was validated with finite element analysis and an experimental prototype linear motor. The coupled model was optimized using a multi-objective genetic algorithm to explore the parameter space and maximize power density and efficiency. An experimental prototype linear pump coupled pistons to an off-the-shelf linear motor to validate the mechanical and pressure dynamics models. The magnetic circuit force calculation agreed within 3% of finite element analysis, and within 8% of experimental data from the unoptimized prototype linear motor. The optimized motor geometry also had good agreement with FEA; at zero piston displacement, the magnetic circuit calculates optimized motor force within 10% of FEA in less than 1/1000 the computational time. This makes it well suited to genetic optimization algorithms. The mechanical model agrees very well with the experimental piston pump position data when tuned for additional unmodeled mechanical friction. Optimized results suggest that an improvement of 400% of the state of the art power density is attainable with as high as 85% net efficiency. This demonstrates that a linear electromagnetic piston pump has potential to serve as a more compact and efficient supply of fluid power for the human scale.

Asynchronous vs didactic education: it’s too early to throw in the towel on tradition

PubMed Central

2013-01-01

Background Asynchronous, computer based instruction is cost effective, allows self-directed pacing and review, and addresses preferences of millennial learners. Current research suggests there is no significant difference in learning compared to traditional classroom instruction. Data are limited for novice learners in emergency medicine. The objective of this study was to compare asynchronous, computer-based instruction with traditional didactics for senior medical students during a week-long intensive course in acute care. We hypothesized both modalities would be equivalent. Methods This was a prospective observational quasi-experimental study of 4th year medical students who were novice learners with minimal prior exposure to curricular elements. We assessed baseline knowledge with an objective pre-test. The curriculum was delivered in either traditional lecture format (shock, acute abdomen, dyspnea, field trauma) or via asynchronous, computer-based modules (chest pain, EKG interpretation, pain management, trauma). An interactive review covering all topics was followed by a post-test. Knowledge retention was measured after 10 weeks. Pre and post-test items were written by a panel of medical educators and validated with a reference group of learners. Mean scores were analyzed using dependent t-test and attitudes were assessed by a 5-point Likert scale. Results 44 of 48 students completed the protocol. Students initially acquired more knowledge from didactic education as demonstrated by mean gain scores (didactic: 28.39% ± 18.06; asynchronous 9.93% ± 23.22). Mean difference between didactic and asynchronous = 18.45% with 95% CI [10.40 to 26.50]; p = 0.0001. Retention testing demonstrated similar knowledge attrition: mean gain scores −14.94% (didactic); -17.61% (asynchronous), which was not significantly different: 2.68% ± 20.85, 95% CI [−3.66 to 9.02], p = 0.399. The attitudinal survey revealed that 60.4% of students believed the asynchronous modules were educational and 95.8% enjoyed the flexibility of the method. 39.6% of students preferred asynchronous education for required didactics; 37.5% were neutral; 23% preferred traditional lectures. Conclusions Asynchronous, computer-based instruction was not equivalent to traditional didactics for novice learners of acute care topics. Interactive, standard didactic education was valuable. Retention rates were similar between instructional methods. Students had mixed attitudes toward asynchronous learning but enjoyed the flexibility. We urge caution in trading in traditional didactic lectures in favor of asynchronous education for novice learners in acute care. PMID:23927420

[A novel proposal explaining sleep disturbance of children in Japan--asynchronization].

PubMed

Kohyama, Jun

2008-07-01

It has been reported that more than half of the children in Japan suffer from daytime sleepiness. In contrast, about one quarter of junior high-school students in Japan complain of insomnia. According to the International Classification of Sleep Disorders (Second edition), these children could be diagnosed as having behaviorally-induced insufficient sleep syndrome due to inadequate sleeping habits. Getting on adequate amount of sleep should solve such problems;however, such a therapeutic approach often fails. Although social factors are involved in these sleep disturbances, I feel that a novel notion - asynchronization - leads to an understanding of the pathophysiology of disturbances in these children. Further, it could contribute to resolve their problems. The essence of asynchronization is a disturbance of various aspects (e.g., cycle, amplitude, phase, and interrelationship) of the biological rhythms that normally exhibits circadian oscillation. The main cause of asynchronization is hypothesized to be the combination of light exposure during night and the lack of light exposure in the morning. Asynchronization results in the disturbance of variable systems. Thus, symptoms of asynchronization include disturbances of the autonomic nervous system (sleepiness, insomnia, disturbance of hormonal excretion, gastrointestinal problems, etc.) and higher brain function (disorientation, loss of sociality, loss of will or motivation, impaired alertness and performance, etc.). Neurological (attention deficit, aggression, impulsiveness, hyperactivity, etc.), psychiatric (depressive disorders, personality disorders, anxiety disorders, etc.) and somatic (tiredness, fatigue, etc.) disturbances could also be symptoms of asynchronization. At the initial phase of asynchronization, disturbances are functional and can be resolved relatively easily, such as by the establishment of a regular sleep-wakefulness cycle;however, without adequate intervention the disturbances could gradually worsen and become hard to resolve.

Evaluation of the applicability of territorial arterial spin labeling in meningiomas for presurgical assessments compared with 3-dimensional time-of-flight magnetic resonance angiography.

PubMed

Lu, Yiping; Luan, Shihai; Liu, Li; Xiong, Ji; Wen, Jianbo; Qu, Jianxun; Geng, Daoying; Yin, Bo

2017-10-01

To prospectively evaluate the application of territorial arterial spin labelling (t-ASL) in comparison with unenhanced three-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA) in the identification of the feeding vasculature of meningiomas. Thirty consecutive patients with suspected meningiomas underwent conventional MR imaging, unenhanced 3D-TOF-MRA and t-ASL scanning. Four experienced neuro-radiologists assessed the feeding vessels with different techniques separately. For the identification of the origin of the feeding arteries on t-ASL, the inter-observer agreement was excellent (к = 0.913), while the inter-observer agreement of 3D-TOF-MRA was good (к = 0.653). The inter-modality agreement between t-ASL and 3D-TOF-MRA for the feeding arteries was moderate (к = 0.514). All 8 patients with motor or sensory disorders proved to have meningiomas supplied completely or partially by the internal carotid arteries, while all 14 patients with meningiomas supplied by the external carotid arteries or basilar arteries didn't show any symptoms concerning motor or sensory disorders (p = 0.003). T-ASL could complement unenhanced 3D-TOF-MRA and increase accuracy in the identification of the supplying arteries of meningiomas in a safe, intuitive, non-radioactive manner. The information about feeding arteries was potentially related to patients' symptoms and pathology, making it more crucial for neurosurgeons in planning surgery as well as evaluating prognosis. • A comprehensive understanding of feeding vasculature is helpful for optimized treatment decisions. • T-ASL could identify main supplying arteries of meningiomas with excellent inter-observer agreement. • The inter-modality agreement for identification of the main feeding arteries was moderate. • Blood supply from ICAs was related to motor or sensory disorders. • High-level meningiomas were found to have double main supplying arteries.

Stand-Alone and Hybrid Positioning Using Asynchronous Pseudolites

PubMed Central

Gioia, Ciro; Borio, Daniele

2015-01-01

global navigation satellite system (GNSS) receivers are usually unable to achieve satisfactory performance in difficult environments, such as open-pit mines, urban canyons and indoors. Pseudolites have the potential to extend GNSS usage and significantly improve receiver performance in such environments by providing additional navigation signals. This also applies to asynchronous pseudolite systems, where different pseudolites operate in an independent way. Asynchronous pseudolite systems require, however, dedicated strategies in order to properly integrate GNSS and pseudolite measurements. In this paper, several asynchronous pseudolite/GNSS integration strategies are considered: loosely- and tightly-coupled approaches are developed and combined with pseudolite proximity and receiver signal strength (RSS)-based positioning. The performance of the approaches proposed has been tested in different scenarios, including static and kinematic conditions. The tests performed demonstrate that the methods developed are effective techniques for integrating heterogeneous measurements from different sources, such as asynchronous pseudolites and GNSS. PMID:25609041

Distributed Consensus of Stochastic Delayed Multi-agent Systems Under Asynchronous Switching.

PubMed

Wu, Xiaotai; Tang, Yang; Cao, Jinde; Zhang, Wenbing

2016-08-01

In this paper, the distributed exponential consensus of stochastic delayed multi-agent systems with nonlinear dynamics is investigated under asynchronous switching. The asynchronous switching considered here is to account for the time of identifying the active modes of multi-agent systems. After receipt of confirmation of mode's switching, the matched controller can be applied, which means that the switching time of the matched controller in each node usually lags behind that of system switching. In order to handle the coexistence of switched signals and stochastic disturbances, a comparison principle of stochastic switched delayed systems is first proved. By means of this extended comparison principle, several easy to verified conditions for the existence of an asynchronously switched distributed controller are derived such that stochastic delayed multi-agent systems with asynchronous switching and nonlinear dynamics can achieve global exponential consensus. Two examples are given to illustrate the effectiveness of the proposed method.

Hydrodynamic advantages of swimming by salp chains.

PubMed

Sutherland, Kelly R; Weihs, Daniel

2017-08-01

Salps are marine invertebrates comprising multiple jet-propelled swimming units during a colonial life-cycle stage. Using theory, we show that asynchronous swimming with multiple pulsed jets yields substantial hydrodynamic benefit due to the production of steady swimming velocities, which limit drag. Laboratory comparisons of swimming kinematics of aggregate salps ( Salpa fusiformis and Weelia cylindrica ) using high-speed video supported that asynchronous swimming by aggregates results in a smoother velocity profile and showed that this smoother velocity profile is the result of uncoordinated, asynchronous swimming by individual zooids. In situ flow visualizations of W. cylindrica swimming wakes revealed that another consequence of asynchronous swimming is that fluid interactions between jet wakes are minimized. Although the advantages of multi-jet propulsion have been mentioned elsewhere, this is the first time that the theory has been quantified and the role of asynchronous swimming verified using experimental data from the laboratory and the field. © 2017 The Author(s).

Motor unit firing and its relation to tremor in the tonic vibration reflex of the decerebrate cat.

PubMed

Clark, F J; Matthews, P B; Muir, R B

1981-01-01

1. The discharge of single motor units has been recorded from the soleus muscle of the decerebrate cat during the tonic vibration reflex elicited isometrically, to further understanding of the tremor that is seen in the reflex contraction. The reflex was elicited by pulses of vibration of 50 micrometers amplitude at 150 Hz, and up to four units were studied concurrently. 2. Individual units fired rather regularly and at a low frequency (range 4-14 Hz). The rate of firing of any unit normally fell within the frequency band of the tremor recorded at the same time. On comparing different preparations a higher frequency of tremor was associated with a higher frequency of motor firing. 3. The responses of pairs of motor units recorded concurrently during repeated production of the reflex were compared by cross-correlation analysis; over 1000 spikes from each train were normally used for this. The major of the cross-correlograms were flat with no overt sign of any synchronization between the units other than that due to the vibration. 4. Clear indications of correlated motor unit firing could be produced deliberately by modulating the amplitude of vibration at a frequency comparable to that of the normal tremor and thereby introducing a rhythmic component into the tonic vibration reflex. 5. About 20% of the cross-correlograms obtained during normal tremor showed varying amounts of an irregular 'waviness' suggesting a possible correlation between the times of firing of a pair of units. But such waves never developed steadily throughout the period of analysis, in contrast to the comparable waves produced on modulating the vibration. Similar waves were seen on cross-correlating a motor unit with an electronic oscillator, confirming that their occurrence does not necessarily demonstrate the existence of active neural interactions. 6. It is concluded that there is no strong and widespread neural synchronizing mechanism active during the tonic vibration reflex, although the possibility of some weak neural interactions has not been excluded. The findings favour the idea that the tremor in this preparation is simply the inevitable result of motor units discharging asynchronously, but at closely similar subtetanic frequencies.

Changes in muscle activity determine progression of clinical symptoms in patients with chronic spine-related muscle pain. A complex clinical and neurophysiological approach

PubMed Central

Wytra̦żek, Marcin; Huber, Juliusz; Lisiński, Przemysław

Summary Spine-related muscle pain can affect muscle strength and motor unit activity. This study was undertaken to investigate whether surface electromyographic (sEMG) recordings performed during relaxation and maximal contraction reveal differences in the activity of muscles with or without trigger points (TRPs). We also analyzed the possible coexistence of characteristic spontaneous activity in needle electromyographic (eEMG) recordings with the presence of TRPs. Thirty patients with non-specific cervical and back pain were evaluated using clinical, neuroimaging and electroneurographic examinations. Muscle pain was measured using a visual analog scale (VAS), and strength using Lovett’s scale; trigger points were detected by palpation. EMG was used to examine motor unit activity. Trigger points were found mainly in the trapezius muscles in thirteen patients. Their presence was accompanied by increased pain intensity, decreased muscle strength, increased resting sEMG amplitude, and decreased sEMG amplitude during muscle contraction. eEMG revealed characteristic asynchronous discharges in TRPs. The results of EMG examinations point to a complexity of muscle pain that depends on progression of the myofascial syndrome PMID:22152435

Merging the Forces of Asynchronous Tutoring and Synchronous Conferencing: A Qualitative Study of Arab ESL Academic Writers Using E-Tutoring

ERIC Educational Resources Information Center

Alqadoumi, Omar Mohamed

2012-01-01

Previous studies in the field of e-tutoring dealt either with asynchronous tutoring or synchronous conferencing as modes for providing e-tutoring services to English learners. This qualitative research study reports the experiences of Arab ESL tutees with both asynchronous tutoring and synchronous conferencing. It also reports the experiences of…

Differences in Electronic Exchanges in Synchronous and Asynchronous Computer-Mediated Communication: The Effect of Culture as a Mediating Variable

ERIC Educational Resources Information Center

Angeli, Charoula; Schwartz, Neil H.

2016-01-01

Two hundred and eighty undergraduates from universities in two countries were asked to read didactic material, and then think and write about potential solutions to an ill-defined problem. The writing was conducted within a synchronous or asynchronous computer-mediated communication (CMC) environment. Asynchronous CMC took the form of email…

Localized radio frequency communication using asynchronous transfer mode protocol

DOEpatents

Witzke, Edward L [Edgewood, NM; Robertson, Perry J [Albuquerque, NM; Pierson, Lyndon G [Albuquerque, NM

2007-08-14

A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

Features of the Asynchronous Correlation between the China Coal Price Index and Coal Mining Accidental Deaths.

PubMed

Huang, Yuecheng; Cheng, Wuyi; Luo, Sida; Luo, Yun; Ma, Chengchen; He, Tailin

2016-01-01

The features of the asynchronous correlation between accident indices and the factors that influence accidents can provide an effective reference for warnings of coal mining accidents. However, what are the features of this correlation? To answer this question, data from the China coal price index and the number of deaths from coal mining accidents were selected as the sample data. The fluctuation modes of the asynchronous correlation between the two data sets were defined according to the asynchronous correlation coefficients, symbolization, and sliding windows. We then built several directed and weighted network models, within which the fluctuation modes and the transformations between modes were represented by nodes and edges. Then, the features of the asynchronous correlation between these two variables could be studied from a perspective of network topology. We found that the correlation between the price index and the accidental deaths was asynchronous and fluctuating. Certain aspects, such as the key fluctuation modes, the subgroups characteristics, the transmission medium, the periodicity and transmission path length in the network, were analyzed by using complex network theory, analytical methods and spectral analysis method. These results provide a scientific reference for generating warnings for coal mining accidents based on economic indices.

Monitoring method and apparatus using high-frequency carrier

DOEpatents

Haynes, Howard D.

1996-01-01

A method and apparatus for monitoring an electrical-motor-driven device by injecting a high frequency carrier signal onto the power line current. The method is accomplished by injecting a high frequency carrier signal onto an AC power line current. The AC power line current supplies the electrical-motor-driven device with electrical energy. As a result, electrical and mechanical characteristics of the electrical-motor-driven device modulate the high frequency carrier signal and the AC power line current. The high frequency carrier signal is then monitored, conditioned and demodulated. Finally, the modulated high frequency carrier signal is analyzed to ascertain the operating condition of the electrical-motor-driven device.

Preparing for possible motor fuel shortages: a community planning guide, Roswell, New Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This guide is prepared to provide a practical approach for the community of Roswell, New Mexico, to respond to fuel supply disruptions. It contains: overviews highlighting fuel supplies and government roles in emergency transportation planning; factors in contingency planning which include community profiles, needs, resources, and constraints; and the local emergency planning process. (MHR)

26 CFR 48.4041-21 - Compressed natural gas (CNG).

Code of Federal Regulations, 2010 CFR

2010-04-01

... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Compressed natural gas (CNG). 48.4041-21 Section... natural gas (CNG). (a) Delivery of CNG into the fuel supply tank of a motor vehicle or motorboat—(1) Imposition of tax. Tax is imposed on the delivery of compressed natural gas (CNG) into the fuel supply tank...

26 CFR 48.4041-21 - Compressed natural gas (CNG).

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 16 2013-04-01 2013-04-01 false Compressed natural gas (CNG). 48.4041-21... natural gas (CNG). (a) Delivery of CNG into the fuel supply tank of a motor vehicle or motorboat—(1) Imposition of tax. Tax is imposed on the delivery of compressed natural gas (CNG) into the fuel supply tank...

26 CFR 48.4041-21 - Compressed natural gas (CNG).

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 16 2012-04-01 2012-04-01 false Compressed natural gas (CNG). 48.4041-21... natural gas (CNG). (a) Delivery of CNG into the fuel supply tank of a motor vehicle or motorboat—(1) Imposition of tax. Tax is imposed on the delivery of compressed natural gas (CNG) into the fuel supply tank...

26 CFR 48.4041-21 - Compressed natural gas (CNG).

Code of Federal Regulations, 2011 CFR

2011-04-01

... 26 Internal Revenue 16 2011-04-01 2011-04-01 false Compressed natural gas (CNG). 48.4041-21... natural gas (CNG). (a) Delivery of CNG into the fuel supply tank of a motor vehicle or motorboat—(1) Imposition of tax. Tax is imposed on the delivery of compressed natural gas (CNG) into the fuel supply tank...

A Simple Demonstration of Back emf

ERIC Educational Resources Information Center

Turner, Lou

2009-01-01

In discussing motors, one college textbook says, "As the coil (of a motor) rotates in a magnetic field, a back emf is generated that tends to counter the emf that supplies the current." This is a true statement, but it does little to enhance student understanding of how and why it is created. In this paper, I will explain how to take students step…

Special-Purpose High-Torque Permanent-Magnet Motors

NASA Technical Reports Server (NTRS)

Doane, George B., III

1995-01-01

Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

Adjustable speed drive study, part 1

NASA Astrophysics Data System (ADS)

Wallace, A.

1989-08-01

Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

Losses in chopper-controlled DC series motors

NASA Technical Reports Server (NTRS)

Hamilton, H. B.

1982-01-01

Motors for electric vehicle (EV) applications must have different features than dc motors designed for industrial applications. The EV motor application is characterized by the following requirements: (1) the need for highest possible efficiency from light load to overload, for maximum EV range, (2) large short time overload capability (The ratio of peak to average power varies from 5/1 in heavy city traffic to 3/1 in suburban driving situations) and (3) operation from power supply voltage levels of 84 to 144 volts (probably 120 volts maximum). A test facility utilizing a dc generator as a substitute for a battery pack was designed and utilized. Criteria for the design of such a facility are presented. Two motors, differing in design detail, commercially available for EV use were tested. Losses measured are discussed, as are waves forms and their harmonic content, the measurements of resistance and inductance, EV motor/chopper application criteria, and motor design considerations.

Bidirectional control system for energy flow in solar powered flywheel

NASA Technical Reports Server (NTRS)

Nola, Frank J. (Inventor)

1987-01-01

An energy storage system for a spacecraft is provided which employs a solar powered flywheel arrangement including a motor/generator which, in different operating modes, drives the flywheel and is driven thereby. A control circuit, including a threshold comparator, senses the output of a solar energy converter, and when a threshold voltage is exceeded thereby indicating the availability of solar power for the spacecraft loads, activates a speed control loop including the motor/generator so as to accelerate the flywheel to a constant speed and thereby store mechanical energy, while also supplying energy from the solar converter to the loads. Under circumstances where solar energy is not available and thus the threshold voltage is not exceeded, the control circuit deactivates the speed control loop and activates a voltage control loop that provides for operation of the motor as a generator so that mechanical energy from the flywheel is converted into electrical energy for supply to the spacecraft loads.

The Effects on Health Behavior and Health Outcomes of Internet-Based Asynchronous Communication Between Health Providers and Patients With a Chronic Condition: A Systematic Review

PubMed Central

Ros, Wynand JG; Schrijvers, Guus

2014-01-01

Background In support of professional practice, asynchronous communication between the patient and the provider is implemented separately or in combination with Internet-based self-management interventions. This interaction occurs primarily through electronic messaging or discussion boards. There is little evidence as to whether it is a useful tool for chronically ill patients to support their self-management and increase the effectiveness of interventions. Objective The aim of our study was to review the use and usability of patient-provider asynchronous communication for chronically ill patients and the effects of such communication on health behavior, health outcomes, and patient satisfaction. Methods A literature search was performed using PubMed and Embase. The quality of the articles was appraised according to the National Institute for Health and Clinical Excellence (NICE) criteria. The use and usability of the asynchronous communication was analyzed by examining the frequency of use and the number of users of the interventions with asynchronous communication, as well as of separate electronic messaging. The effectiveness of asynchronous communication was analyzed by examining effects on health behavior, health outcomes, and patient satisfaction. Results Patients’ knowledge concerning their chronic condition increased and they seemed to appreciate being able to communicate asynchronously with their providers. They not only had specific questions but also wanted to communicate about feeling ill. A decrease in visits to the physician was shown in two studies (P=.07, P=.07). Increases in self-management/self-efficacy for patients with back pain, dyspnea, and heart failure were found. Positive health outcomes were shown in 12 studies, where the clinical outcomes for diabetic patients (HbA1c level) and for asthmatic patients (forced expiratory volume [FEV]) improved. Physical symptoms improved in five studies. Five studies generated a variety of positive psychosocial outcomes. Conclusions The effect of asynchronous communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed. PMID:24434570

The effects on health behavior and health outcomes of Internet-based asynchronous communication between health providers and patients with a chronic condition: a systematic review.

PubMed

de Jong, Catharina Carolina; Ros, Wynand Jg; Schrijvers, Guus

2014-01-16

In support of professional practice, asynchronous communication between the patient and the provider is implemented separately or in combination with Internet-based self-management interventions. This interaction occurs primarily through electronic messaging or discussion boards. There is little evidence as to whether it is a useful tool for chronically ill patients to support their self-management and increase the effectiveness of interventions. The aim of our study was to review the use and usability of patient-provider asynchronous communication for chronically ill patients and the effects of such communication on health behavior, health outcomes, and patient satisfaction. A literature search was performed using PubMed and Embase. The quality of the articles was appraised according to the National Institute for Health and Clinical Excellence (NICE) criteria. The use and usability of the asynchronous communication was analyzed by examining the frequency of use and the number of users of the interventions with asynchronous communication, as well as of separate electronic messaging. The effectiveness of asynchronous communication was analyzed by examining effects on health behavior, health outcomes, and patient satisfaction. Patients' knowledge concerning their chronic condition increased and they seemed to appreciate being able to communicate asynchronously with their providers. They not only had specific questions but also wanted to communicate about feeling ill. A decrease in visits to the physician was shown in two studies (P=.07, P=.07). Increases in self-management/self-efficacy for patients with back pain, dyspnea, and heart failure were found. Positive health outcomes were shown in 12 studies, where the clinical outcomes for diabetic patients (HbA1c level) and for asthmatic patients (forced expiratory volume [FEV]) improved. Physical symptoms improved in five studies. Five studies generated a variety of positive psychosocial outcomes. The effect of asynchronous communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed.

Hysteresis, phase transitions, and dangerous transients in electrical power distribution systems

NASA Astrophysics Data System (ADS)

Duclut, Charlie; Backhaus, Scott; Chertkov, Michael

2013-06-01

The majority of dynamical studies in power systems focus on the high-voltage transmission grids where models consider large generators interacting with crude aggregations of individual small loads. However, new phenomena have been observed indicating that the spatial distribution of collective, nonlinear contribution of these small loads in the low-voltage distribution grid is crucial to the outcome of these dynamical transients. To elucidate the phenomenon, we study the dynamics of voltage and power flows in a spatially extended distribution feeder (circuit) connecting many asynchronous induction motors and discover that this relatively simple 1+1 (space+time) dimensional system exhibits a plethora of nontrivial spatiotemporal effects, some of which may be dangerous for power system stability. Long-range motor-motor interactions mediated by circuit voltage and electrical power flows result in coexistence and segregation of spatially extended phases defined by individual motor states, a “normal” state where the motors’ mechanical (rotation) frequency is slightly smaller than the nominal frequency of the basic ac flows and a “stalled” state where the mechanical frequency is small. Transitions between the two states can be initiated by a perturbation of the voltage or base frequency at the head of the distribution feeder. Such behavior is typical of first-order phase transitions in physics, and this 1+1 dimensional model shows many other properties of a first-order phase transition with the spatial distribution of the motors’ mechanical frequency playing the role of the order parameter. In particular, we observe (a) propagation of the phase-transition front with the constant speed (in very long feeders) and (b) hysteresis in transitions between the normal and stalled (or partially stalled) phases.

Preliminary design for a standard 10 sup 7 bit Solid State Memory (SSM)

NASA Technical Reports Server (NTRS)

Hayes, P. J.; Howle, W. M., Jr.; Stermer, R. L., Jr.

1978-01-01

A modular concept with three separate modules roughly separating bubble domain technology, control logic technology, and power supply technology was employed. These modules were respectively the standard memory module (SMM), the data control unit (DCU), and power supply module (PSM). The storage medium was provided by bubble domain chips organized into memory cells. These cells and the circuitry for parallel data access to the cells make up the SMM. The DCU provides a flexible serial data interface to the SMM. The PSM provides adequate power to enable one DCU and one SMM to operate simultaneously at the maximum data rate. The SSM was designed to handle asynchronous data rates from dc to 1.024 Mbs with a bit error rate less than 1 error in 10 to the eight power bits. Two versions of the SSM, a serial data memory and a dual parallel data memory were specified using the standard modules. The SSM specification includes requirements for radiation hardness, temperature and mechanical environments, dc magnetic field emission and susceptibility, electromagnetic compatibility, and reliability.

Na+-driven bacterial flagellar motors.

PubMed

Imae, Y; Atsumi, T

1989-12-01

Bacterial flagellar motors are the reversible rotary engine which propels the cell by rotating a helical flagellar filament as a screw propeller. The motors are embedded in the cytoplasmic membrane, and the energy for rotation is supplied by the electrochemical potential of specific ions across the membrane. Thus, the analysis of motor rotation at the molecular level is linked to an understanding of how the living system converts chemical energy into mechanical work. Based on the coupling ions, the motors are divided into two types; one is the H+-driven type found in neutrophiles such as Bacillus subtilis and Escherichia coli and the other is the Na+-driven type found in alkalophilic Bacillus and marine Vibrio. In this review, we summarize the current status of research on the rotation mechanism of the Na+-driven flagellar motors, which introduces several new aspects in the analysis.

Experimental Research in Boost Driver with EDLCs

NASA Astrophysics Data System (ADS)

Matsumoto, Hirokazu

The supply used in servo systems tends to have a high voltage in order to reduce loss and improve the response of motor drives. We propose a new boost motor driver that comprises EDLCs. The proposed driver has a simple structure, wherein the EDLCs are connected in series to the supply, and comprises a charge circuit to charge the EDLCs. The proposed driver has three advantages over conventional boost drivers. The first advantage is that the driver can easily attain the stable boost voltage. The second advantage is that the driver can reduce input power peaks. In a servo system, the input power peaks become greater than the rated power in order to accelerate the motor rapidly. This implies that the equipments that supply power to servo systems must have sufficient power capacity to satisfy the power peaks. The proposed driver can suppress the increase of the power capacity of supply facilities. The third advantage is that the driver can store almost all of the regenerative energy. Conventional drivers have a braking resistor to suppress the increase in the DC link voltage. This causes a considerable reduction in the efficiency. The proposed driver is more efficient than conventional drivers. In this study, the experimental results confirmed the effectiveness of the proposed driver and showed that the drive performance of the proposed driver is the same as that of a conventional driver. Furthermore, it was confirmed that the results of the simulation of a model of the EDLC module, whose capacitance is dependent on the frequency, correspond well with the experimental results.

Asynchronous vibration problem of centrifugal compressor

NASA Technical Reports Server (NTRS)

Fujikawa, T.; Ishiguro, N.; Ito, M.

1980-01-01

An unstable asynchronous vibration problem in a high pressure centrifugal compressor and the remedial actions against it are described. Asynchronous vibration of the compressor took place when the discharge pressure (Pd) was increased, after the rotor was already at full speed. The typical spectral data of the shaft vibration indicate that as the pressure Pd increases, pre-unstable vibration appears and becomes larger, and large unstable asynchronous vibration occurs suddenly (Pd = 5.49MPa). A computer program was used which calculated the logarithmic decrement and the damped natural frequency of the rotor bearing systems. The analysis of the log-decrement is concluded to be effective in preventing unstable vibration in both the design stage and remedial actions.

A study on various methods of supplying propellant to an orbit insertion rocket engine

NASA Technical Reports Server (NTRS)

Boretz, J. E.; Huniu, S.; Thompson, M.; Pagani, M.; Paulsen, B.; Lewis, J.; Paul, D.

1980-01-01

Various types of pumps and pump drives were evaluated to determine the lightest weight system for supplying propellants to a planetary orbit insertion rocket engine. From these analyses four candidate propellant feed systems were identified. Systems Nos. 1 and 2 were both battery powered (lithium-thionyl-chloride or silver-zinc) motor driven pumps. System 3 was a monopropellant gas generator powered turbopump. System 4 was a bipropellant gas generator powered turbopump. Parameters considered were pump break horsepower, weight, reliability, transient response and system stability. Figures of merit were established and the ranking of the candidate systems was determined. Conceptual designs were prepared for typical motor driven pumps and turbopump configurations for a 1000 lbf thrust rocket engine.

Optimization of parameters of special asynchronous electric drives

NASA Astrophysics Data System (ADS)

Karandey, V. Yu; Popov, B. K.; Popova, O. B.; Afanasyev, V. L.

2018-03-01

The article considers the solution of the problem of parameters optimization of special asynchronous electric drives. The solution of the problem will allow one to project and create special asynchronous electric drives for various industries. The created types of electric drives will have optimum mass-dimensional and power parameters. It will allow one to realize and fulfill the set characteristics of management of technological processes with optimum level of expenses of electric energy, time of completing the process or other set parameters. The received decision allows one not only to solve a certain optimizing problem, but also to construct dependences between the optimized parameters of special asynchronous electric drives, for example, with the change of power, current in a winding of the stator or rotor, induction in a gap or steel of magnetic conductors and other parameters. On the constructed dependences, it is possible to choose necessary optimum values of parameters of special asynchronous electric drives and their components without carrying out repeated calculations.

Asynchronous Communication of TLNS3DMB Boundary Exchange

NASA Technical Reports Server (NTRS)

Hammond, Dana P.

1997-01-01

This paper describes the recognition of implicit serialization due to coarse-grain, synchronous communication and demonstrates the conversion to asynchronous communication for the exchange of boundary condition information in the Thin-Layer Navier Stokes 3-Dimensional Multi Block (TLNS3DMB) code. The implementation details of using asynchronous communication is provided including buffer allocation, message identification, and barrier control. The IBM SP2 was used for the tests presented.

[Cost-effectiveness of Synchronous vs. Asynchronous Telepsychiatry in Prison Inmates With Depression].

PubMed

Barrera-Valencia, Camilo; Benito-Devia, Alexis Vladimir; Vélez-Álvarez, Consuelo; Figueroa-Barrera, Mario; Franco-Idárraga, Sandra Milena

Telepsychiatry is defined as the use of information and communication technology (ICT) in providing remote psychiatric services. Telepsychiatry is applied using two types of communication: synchronous (real time) and asynchronous (store and forward). To determine the cost-effectiveness of a synchronous and an asynchronous telepsychiatric model in prison inmate patients with symptoms of depression. A cost-effectiveness study was performed on a population consisting of 157 patients from the Establecimiento Penitenciario y Carcelario de Mediana Seguridad de Manizales, Colombia. The sample was determined by applying Zung self-administered surveys for depression (1965) and the Hamilton Depression Rating Scale (HDRS), the latter being the tool used for the comparison. Initial Hamilton score, arrival time, duration of system downtime, and clinical effectiveness variables had normal distributions (P>.05). There were significant differences (P<.001) between care costs for the different models, showing that the mean cost of the asynchronous model is less than synchronous model, and making the asynchronous model more cost-effective. The asynchronous model is the most cost-effective model of telepsychiatry care for patients with depression admitted to a detention centre, according to the results of clinical effectiveness, cost measurement, and patient satisfaction. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Features of the Asynchronous Correlation between the China Coal Price Index and Coal Mining Accidental Deaths

PubMed Central

Huang, Yuecheng; Cheng, Wuyi; Luo, Sida; Luo, Yun; Ma, Chengchen; He, Tailin

2016-01-01

The features of the asynchronous correlation between accident indices and the factors that influence accidents can provide an effective reference for warnings of coal mining accidents. However, what are the features of this correlation? To answer this question, data from the China coal price index and the number of deaths from coal mining accidents were selected as the sample data. The fluctuation modes of the asynchronous correlation between the two data sets were defined according to the asynchronous correlation coefficients, symbolization, and sliding windows. We then built several directed and weighted network models, within which the fluctuation modes and the transformations between modes were represented by nodes and edges. Then, the features of the asynchronous correlation between these two variables could be studied from a perspective of network topology. We found that the correlation between the price index and the accidental deaths was asynchronous and fluctuating. Certain aspects, such as the key fluctuation modes, the subgroups characteristics, the transmission medium, the periodicity and transmission path length in the network, were analyzed by using complex network theory, analytical methods and spectral analysis method. These results provide a scientific reference for generating warnings for coal mining accidents based on economic indices. PMID:27902748

Efficacy of an asynchronous electronic curriculum in emergency medicine education in the United States.

PubMed

Wray, Alisa; Bennett, Kathryn; Boysen-Osborn, Megan; Wiechmann, Warren; Toohey, Shannon

2017-01-01

The aim of this study was to measure the effect of an iPad-based asynchronous curriculum on emergency medicine resident performance on the in-training exam (ITE). We hypothesized that the implementation of an asynchronous curriculum (replacing 1 hour of weekly didactic time) would result in non-inferior ITE scores compared to the historical scores of residents who had participated in the traditional 5-hour weekly didactic curriculum. The study was a retrospective, non-inferiority study. conducted at the University of California, Irvine Emergency Medicine Residency Program. We compared ITE scores from 2012 and 2013, when there were 5 weekly hours of didactic content, with scores from 2014 and 2015, when 1 hour of conference was replaced with asynchro-nous content. Examination results were compared using a non-inferiority data analysis with a 10% margin of difference. Using a non-inferiority test with a 95% confidence interval, there was no difference between the 2 groups (before and after implementation of asynchronous learning), as the confidence interval for the change of the ITE was -3.5 to 2.3 points, whereas the 10% non-inferiority margin was 7.8 points. Replacing 1 hour of didactic conference with asynchronous learning showed no negative impact on resident ITE scores.

Classification of Movement and Inhibition Using a Hybrid BCI.

PubMed

Chmura, Jennifer; Rosing, Joshua; Collazos, Steven; Goodwin, Shikha J

2017-01-01

Brain-computer interfaces (BCIs) are an emerging technology that are capable of turning brain electrical activity into commands for an external device. Motor imagery (MI)-when a person imagines a motion without executing it-is widely employed in BCI devices for motor control because of the endogenous origin of its neural control mechanisms, and the similarity in brain activation to actual movements. Challenges with translating a MI-BCI into a practical device used outside laboratories include the extensive training required, often due to poor user engagement and visual feedback response delays; poor user flexibility/freedom to time the execution/inhibition of their movements, and to control the movement type (right arm vs. left leg) and characteristics (reaching vs. grabbing); and high false positive rates of motion control. Solutions to improve sensorimotor activation and user performance of MI-BCIs have been explored. Virtual reality (VR) motor-execution tasks have replaced simpler visual feedback (smiling faces, arrows) and have solved this problem to an extent. Hybrid BCIs (hBCIs) implementing an additional control signal to MI have improved user control capabilities to a limited extent. These hBCIs either fail to allow the patients to gain asynchronous control of their movements, or have a high false positive rate. We propose an immersive VR environment which provides visual feedback that is both engaging and immediate, but also uniquely engages a different cognitive process in the patient that generates event-related potentials (ERPs). These ERPs provide a key executive function for the users to execute/inhibit movements. Additionally, we propose signal processing strategies and machine learning algorithms to move BCIs toward developing long-term signal stability in patients with distinctive brain signals and capabilities to control motor signals. The hBCI itself and the VR environment we propose would help to move BCI technology outside laboratory environments for motor rehabilitation in hospitals, and potentially for controlling a prosthetic.

Classification of Movement and Inhibition Using a Hybrid BCI

PubMed Central

Chmura, Jennifer; Rosing, Joshua; Collazos, Steven; Goodwin, Shikha J.

2017-01-01

Brain-computer interfaces (BCIs) are an emerging technology that are capable of turning brain electrical activity into commands for an external device. Motor imagery (MI)—when a person imagines a motion without executing it—is widely employed in BCI devices for motor control because of the endogenous origin of its neural control mechanisms, and the similarity in brain activation to actual movements. Challenges with translating a MI-BCI into a practical device used outside laboratories include the extensive training required, often due to poor user engagement and visual feedback response delays; poor user flexibility/freedom to time the execution/inhibition of their movements, and to control the movement type (right arm vs. left leg) and characteristics (reaching vs. grabbing); and high false positive rates of motion control. Solutions to improve sensorimotor activation and user performance of MI-BCIs have been explored. Virtual reality (VR) motor-execution tasks have replaced simpler visual feedback (smiling faces, arrows) and have solved this problem to an extent. Hybrid BCIs (hBCIs) implementing an additional control signal to MI have improved user control capabilities to a limited extent. These hBCIs either fail to allow the patients to gain asynchronous control of their movements, or have a high false positive rate. We propose an immersive VR environment which provides visual feedback that is both engaging and immediate, but also uniquely engages a different cognitive process in the patient that generates event-related potentials (ERPs). These ERPs provide a key executive function for the users to execute/inhibit movements. Additionally, we propose signal processing strategies and machine learning algorithms to move BCIs toward developing long-term signal stability in patients with distinctive brain signals and capabilities to control motor signals. The hBCI itself and the VR environment we propose would help to move BCI technology outside laboratory environments for motor rehabilitation in hospitals, and potentially for controlling a prosthetic. PMID:28860986

Design and implementation of a prototype micropositioning and fusion of optical fibers

NASA Astrophysics Data System (ADS)

Vega, Fabio; Torres, Cesar; Mattos, Lorenzo

2011-09-01

We developed an automated system in micro and optical fiber fusion, using stepper motors of 3.6 ° (1.8 ° Medium step) with a threaded system for displacements in the order of microns, a LM016 LCD for User message management, a PIC16F877A microcontroller to control the prototype. We also used internal modules: TMR0, EEPROM, PWM (pulse width modulation) control using a pulse opto-cupped the discharge circuit high voltage (20 to 35 kilovolt transformer for FLYBACK fusion) The USART (Universal Synchronous Asynchronous Receiver Transmitter) for serial interface with the PC. The software platform developed under Visual Basic 6.0, which lets you manipulate the prototype from the PC. The entire program is optimized for microcontroller interrupt, macro-functions and is written in MPLAB 7.31. The prototype is now finished.

Straight and chopped dc performance data for a General Electric 5BT 2366C10 motor and an EV-1 controller

NASA Technical Reports Server (NTRS)

Edie, P. C.

1981-01-01

Performance data on the General Electric 5BT 2366C10 series wound dc motor and EV-1 Chopper Controller is supplied for the electric vehicle manufacturer. Data is provided for both straight and chopped dc input to the motor, at 2 motor temperature levels. Testing was done at 6 voltage increments to the motor, and 2 voltage increments to the controller. Data results are presented in both tabular and graphical forms. Tabular information includes motor voltage and current input data, motor speed and torque output data, power data and temperature data. Graphical information includes torque-speed, motor power output-speed, torque-current, and efficiency-speed plots under the various operating conditions. The data resulting from this testing shows the speed-torque plots to have the most variance with operating temperature. The maximum motor efficiency is between 86% and 87%, regardless of temperature or mode of operation. When the chopper is utilized, maximum motor efficiency occurs when the chopper duty cycle approaches 100%.

26 CFR 48.4041-5 - Sales of diesel and special motor fuels and fuel for use in aircraft; rules of general application.

Code of Federal Regulations, 2010 CFR

2010-04-01

... for use in aircraft; rules of general application. (a) Taxability of liquid fuel delivered into... of a motor vehicle or motorboat, or of fuel to an owner, lessee, or other operator of an aircraft... delivered by the seller into the fuel supply tank of the vehicle, motorboat, or aircraft. For purpose of...

WE-G-213CD-06: Implementation of Real-Time Tumor Tracking Using Robotic Couch.

PubMed

Buzurovic, I; Yu, Y; Podder, T

2012-06-01

The purpose of this study was to present a novel method for real- time tumor tracking using a commercially available robotic treatment couch, and to evaluate tumor tracking accuracy. Commercially available robotic couches are capable of positioning patients with high level of accuracy; however, currently there is no provision for compensating tumor motion using these systems. Elekta's existing commercial couch (PreciseTM Table) was used without changing its design. To establish the real-time couch motion for tracking, a novel control system was developed and implemented. The tabletop could be moved in horizontal plane (laterally and longitudinally) using two Maxon-24V motors with gearbox combination. Vertical motion was obtained using robust 70V-Rockwell Automation motor. For vertical motor position sensing, we used Model 755A-Accu- Coder encoder. Two Baumer-ITD_01_4mm shaft encoders were used for the lateral and longitudinal motions of the couch. Motors were connected to the Advance Motion Controls (AMC) amplifiers: for the vertical motion, motor AMC-20A20-INV amplifier was used, and two AMC-Z6A8 amplifiers were applied for the lateral and longitudinal couch motions. The Galil DMC-4133 controller was connected to standard PC computer using USB port. The system had two independent power supplies: Galil PSR-12- 24-12A, 24vdc power supply with diodes for controller and 24vdc motors and amplifiers, and Galil-PS300W72 72vdc power supply for vertical motion. Control algorithms were developed for position and velocity adjustment. The system was tested for real-time tracking in the range of 50mm in all 3 directions (superior-inferior, lateral, anterior- posterior). Accuracies were 0.15, 0.20, and 0.18mm, respectively. Repeatability of the desired motion was within ± 0.2mm. Experimental results of couch tracking show feasibility of real-time tumor tracking with high level of accuracy (within sub-millimeter range). This tracking technique potentially offers a simple and effective method to minimize healthy tissues irradiation.Acknowledgement: Study supported by Elekta,Ltd. Study supported by Elekta, Ltd. © 2012 American Association of Physicists in Medicine.

Adjustable speed drive study, June 1985 to September 1988. Part 2: Appendices

NASA Astrophysics Data System (ADS)

Wallace, Alan

1989-08-01

Advances in speed control for motors in recent years, notably those in power electronics, have widened the range of application for several adjustable speed drive (ASD) types to include the smaller horsepower sizes. The dc motor drive, formerly in almost universal use for speed control, is being challenged by the high efficiency induction motor/pulse width modulation (PWM) drive; and for special small horsepower size applications, by the permanent magnet motor/PWM inverter drive or by the switched reluctance motor drive. The main characteristics of the several ASD types suitable for small horsepower size applications are discussed, as well as their unwanted side effects: poor power factor, harmonic distortion of the supply, acoustic noise, and electromagnetic interference. A procedure is recommended for determining which, if any, ASD to use.

In-situ Condition Monitoring of Components in Small Modular Reactors Using Process and Electrical Signature Analysis. Final report, volume 1. Development of experimental flow control loop, data analysis and plant monitoring

DOE Office of Scientific and Technical Information (OSTI.GOV)

Upadhyaya, Belle; Hines, J. Wesley; Damiano, Brian

The research and development under this project was focused on the following three major objectives: Objective 1: Identification of critical in-vessel SMR components for remote monitoring and development of their low-order dynamic models, along with a simulation model of an integral pressurized water reactor (iPWR). Objective 2: Development of an experimental flow control loop with motor-driven valves and pumps, incorporating data acquisition and on-line monitoring interface. Objective 3: Development of stationary and transient signal processing methods for electrical signatures, machinery vibration, and for characterizing process variables for equipment monitoring. This objective includes the development of a data analysis toolbox. Themore » following is a summary of the technical accomplishments under this project: - A detailed literature review of various SMR types and electrical signature analysis of motor-driven systems was completed. A bibliography of literature is provided at the end of this report. Assistance was provided by ORNL in identifying some key references. - A review of literature on pump-motor modeling and digital signal processing methods was performed. - An existing flow control loop was upgraded with new instrumentation, data acquisition hardware and software. The upgrading of the experimental loop included the installation of a new submersible pump driven by a three-phase induction motor. All the sensors were calibrated before full-scale experimental runs were performed. - MATLAB-Simulink model of a three-phase induction motor and pump system was completed. The model was used to simulate normal operation and fault conditions in the motor-pump system, and to identify changes in the electrical signatures. - A simulation model of an integral PWR (iPWR) was updated and the MATLAB-Simulink model was validated for known transients. The pump-motor model was interfaced with the iPWR model for testing the impact of primary flow perturbations (upsets) on plant parameters and the pump electrical signatures. Additionally, the reactor simulation is being used to generate normal operation data and data with instrumentation faults and process anomalies. A frequency controller was interfaced with the motor power supply in order to vary the electrical supply frequency. The experimental flow control loop was used to generate operational data under varying motor performance characteristics. Coolant leakage events were simulated by varying the bypass loop flow rate. The accuracy of motor power calculation was improved by incorporating the power factor, computed from motor current and voltage in each phase of the induction motor.- A variety of experimental runs were made for steady-state and transient pump operating conditions. Process, vibration, and electrical signatures were measured using a submersible pump with variable supply frequency. High correlation was seen between motor current and pump discharge pressure signal; similar high correlation was exhibited between pump motor power and flow rate. Wide-band analysis indicated high coherence (in the frequency domain) between motor current and vibration signals. - Wide-band operational data from a PWR were acquired from AMS Corporation and used to develop time-series models, and to estimate signal spectrum and sensor time constant. All the data were from different pressure transmitters in the system, including primary and secondary loops. These signals were pre-processed using the wavelet transform for filtering both low-frequency and high-frequency bands. This technique of signal pre-processing provides minimum distortion of the data, and results in a more optimal estimation of time constants of plant sensors using time-series modeling techniques.« less

Monitoring method and apparatus using high-frequency carrier

DOEpatents

Haynes, H.D.

1996-04-30

A method and apparatus for monitoring an electrical-motor-driven device by injecting a high frequency carrier signal onto the power line current. The method is accomplished by injecting a high frequency carrier signal onto an AC power line current. The AC power line current supplies the electrical-motor-driven device with electrical energy. As a result, electrical and mechanical characteristics of the electrical-motor-driven device modulate the high frequency carrier signal and the AC power line current. The high frequency carrier signal is then monitored, conditioned and demodulated. Finally, the modulated high frequency carrier signal is analyzed to ascertain the operating condition of the electrical-motor-driven device. 6 figs.

A high efficiency motor/generator for magnetically suspended flywheel energy storage system

NASA Technical Reports Server (NTRS)

Niemeyer, W. L.; Studer, P.; Kirk, J. A.; Anand, D. K.; Zmood, R. B.

1989-01-01

The authors discuss the theory and design of a brushless direct current motor for use in a flywheel energy storage system. The motor design is optimized for a nominal 4.5-in outside diameter operating within a speed range of 33,000-66,000 revolutions per minute with a 140-V maximum supply voltage. The equations which govern the motor's operation are used to compute a series of acceptable design parameter combinations for ideal operation. Engineering tradeoffs are then performed to minimize the irrecoverable energy loss while remaining within the design constraint boundaries. A final integrated structural design whose features allow it to be incorporated with the 500-Wh magnetically suspended flywheel is presented.

Asynchronous networks: modularization of dynamics theorem

NASA Astrophysics Data System (ADS)

Bick, Christian; Field, Michael

2017-02-01

Building on the first part of this paper, we develop the theory of functional asynchronous networks. We show that a large class of functional asynchronous networks can be (uniquely) represented as feedforward networks connecting events or dynamical modules. For these networks we can give a complete description of the network function in terms of the function of the events comprising the network: the modularization of dynamics theorem. We give examples to illustrate the main results.

Distributed Data-aggregation Consensus for Sensor Networks: Relaxation of Consensus Concept and Convergence Property

DTIC Science & Technology

2014-08-01

consensus algorithm called randomized gossip is more suitable [7, 8]. In asynchronous randomized gossip algorithms, pairs of neighboring nodes exchange...messages and perform updates in an asynchronous and unattended manner, and they also 1 The class of broadcast gossip algorithms [9, 10, 11, 12] are...dynamics [2] and asynchronous pairwise randomized gossip [7, 8], broadcast gossip algorithms do not require that nodes know the identities of their

Simulating fail-stop in asynchronous distributed systems

NASA Technical Reports Server (NTRS)

Sabel, Laura; Marzullo, Keith

1994-01-01

The fail-stop failure model appears frequently in the distributed systems literature. However, in an asynchronous distributed system, the fail-stop model cannot be implemented. In particular, it is impossible to reliably detect crash failures in an asynchronous system. In this paper, we show that it is possible to specify and implement a failure model that is indistinguishable from the fail-stop model from the point of view of any process within an asynchronous system. We give necessary conditions for a failure model to be indistinguishable from the fail-stop model, and derive lower bounds on the amount of process replication needed to implement such a failure model. We present a simple one-round protocol for implementing one such failure model, which we call simulated fail-stop.

Asynchronous Video Interviewing as a New Technology in Personnel Selection: The Applicant’s Point of View

PubMed Central

Brenner, Falko S.; Ortner, Tuulia M.; Fay, Doris

2016-01-01

The present study aimed to integrate findings from technology acceptance research with research on applicant reactions to new technology for the emerging selection procedure of asynchronous video interviewing. One hundred six volunteers experienced asynchronous video interviewing and filled out several questionnaires including one on the applicants’ personalities. In line with previous technology acceptance research, the data revealed that perceived usefulness and perceived ease of use predicted attitudes toward asynchronous video interviewing. Furthermore, openness revealed to moderate the relation between perceived usefulness and attitudes toward this particular selection technology. No significant effects emerged for computer self-efficacy, job interview self-efficacy, extraversion, neuroticism, and conscientiousness. Theoretical and practical implications are discussed. PMID:27378969

Hyperbaric Oxygen Environment Can Enhance Brain Activity and Multitasking Performance

PubMed Central

Vadas, Dor; Kalichman, Leonid; Hadanny, Amir; Efrati, Shai

2017-01-01

Background: The Brain uses 20% of the total oxygen supply consumed by the entire body. Even though, <10% of the brain is active at any given time, it utilizes almost all the oxygen delivered. In order to perform complex tasks or more than one task (multitasking), the oxygen supply is shifted from one brain region to another, via blood perfusion modulation. The aim of the present study was to evaluate whether a hyperbaric oxygen (HBO) environment, with increased oxygen supply to the brain, will enhance the performance of complex and/or multiple activities. Methods: A prospective, double-blind randomized control, crossover trial including 22 healthy volunteers. Participants were asked to perform a cognitive task, a motor task and a simultaneous cognitive-motor task (multitasking). Participants were randomized to perform the tasks in two environments: (a) normobaric air (1 ATA 21% oxygen) (b) HBO (2 ATA 100% oxygen). Two weeks later participants were crossed to the alternative environment. Blinding of the normobaric environment was achieved in the same chamber with masks on while hyperbaric sensation was simulated by increasing pressure in the first minute and gradually decreasing to normobaric environment prior to tasks performance. Results: Compared to the performance at normobaric conditions, both cognitive and motor single tasks scores were significantly enhanced by HBO environment (p < 0.001 for both). Multitasking performance was also significantly enhanced in HBO environment (p = 0.006 for the cognitive part and p = 0.02 for the motor part). Conclusions: The improvement in performance of both single and multi-tasking while in an HBO environment supports the hypothesis which according to, oxygen is indeed a rate limiting factor for brain activity. Hyperbaric oxygenation can serve as an environment for brain performance. Further studies are needed to evaluate the optimal oxygen levels for maximal brain performance. PMID:29021747

Hyperbaric Oxygen Environment Can Enhance Brain Activity and Multitasking Performance.

PubMed

Vadas, Dor; Kalichman, Leonid; Hadanny, Amir; Efrati, Shai

2017-01-01

Background: The Brain uses 20% of the total oxygen supply consumed by the entire body. Even though, <10% of the brain is active at any given time, it utilizes almost all the oxygen delivered. In order to perform complex tasks or more than one task (multitasking), the oxygen supply is shifted from one brain region to another, via blood perfusion modulation. The aim of the present study was to evaluate whether a hyperbaric oxygen (HBO) environment, with increased oxygen supply to the brain, will enhance the performance of complex and/or multiple activities. Methods: A prospective, double-blind randomized control, crossover trial including 22 healthy volunteers. Participants were asked to perform a cognitive task, a motor task and a simultaneous cognitive-motor task (multitasking). Participants were randomized to perform the tasks in two environments: (a) normobaric air (1 ATA 21% oxygen) (b) HBO (2 ATA 100% oxygen). Two weeks later participants were crossed to the alternative environment. Blinding of the normobaric environment was achieved in the same chamber with masks on while hyperbaric sensation was simulated by increasing pressure in the first minute and gradually decreasing to normobaric environment prior to tasks performance. Results: Compared to the performance at normobaric conditions, both cognitive and motor single tasks scores were significantly enhanced by HBO environment ( p < 0.001 for both). Multitasking performance was also significantly enhanced in HBO environment ( p = 0.006 for the cognitive part and p = 0.02 for the motor part). Conclusions: The improvement in performance of both single and multi-tasking while in an HBO environment supports the hypothesis which according to, oxygen is indeed a rate limiting factor for brain activity. Hyperbaric oxygenation can serve as an environment for brain performance. Further studies are needed to evaluate the optimal oxygen levels for maximal brain performance.

Network evolution induced by asynchronous stimuli through spike-timing-dependent plasticity.

PubMed

Yuan, Wu-Jie; Zhou, Jian-Fang; Zhou, Changsong

2013-01-01

In sensory neural system, external asynchronous stimuli play an important role in perceptual learning, associative memory and map development. However, the organization of structure and dynamics of neural networks induced by external asynchronous stimuli are not well understood. Spike-timing-dependent plasticity (STDP) is a typical synaptic plasticity that has been extensively found in the sensory systems and that has received much theoretical attention. This synaptic plasticity is highly sensitive to correlations between pre- and postsynaptic firings. Thus, STDP is expected to play an important role in response to external asynchronous stimuli, which can induce segregative pre- and postsynaptic firings. In this paper, we study the impact of external asynchronous stimuli on the organization of structure and dynamics of neural networks through STDP. We construct a two-dimensional spatial neural network model with local connectivity and sparseness, and use external currents to stimulate alternately on different spatial layers. The adopted external currents imposed alternately on spatial layers can be here regarded as external asynchronous stimuli. Through extensive numerical simulations, we focus on the effects of stimulus number and inter-stimulus timing on synaptic connecting weights and the property of propagation dynamics in the resulting network structure. Interestingly, the resulting feedforward structure induced by stimulus-dependent asynchronous firings and its propagation dynamics reflect both the underlying property of STDP. The results imply a possible important role of STDP in generating feedforward structure and collective propagation activity required for experience-dependent map plasticity in developing in vivo sensory pathways and cortices. The relevance of the results to cue-triggered recall of learned temporal sequences, an important cognitive function, is briefly discussed as well. Furthermore, this finding suggests a potential application for examining STDP by measuring neural population activity in a cultured neural network.

FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

NASA Astrophysics Data System (ADS)

Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

2014-09-01

Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to compose asynchronous GSO workflows. Most importantly, it provides better support for locating and diagnosing potential exceptions.

Asynchronous collision integrators: Explicit treatment of unilateral contact with friction and nodal restraints

PubMed Central

Wolff, Sebastian; Bucher, Christian

2013-01-01

This article presents asynchronous collision integrators and a simple asynchronous method treating nodal restraints. Asynchronous discretizations allow individual time step sizes for each spatial region, improving the efficiency of explicit time stepping for finite element meshes with heterogeneous element sizes. The article first introduces asynchronous variational integration being expressed by drift and kick operators. Linear nodal restraint conditions are solved by a simple projection of the forces that is shown to be equivalent to RATTLE. Unilateral contact is solved by an asynchronous variant of decomposition contact response. Therein, velocities are modified avoiding penetrations. Although decomposition contact response is solving a large system of linear equations (being critical for the numerical efficiency of explicit time stepping schemes) and is needing special treatment regarding overconstraint and linear dependency of the contact constraints (for example from double-sided node-to-surface contact or self-contact), the asynchronous strategy handles these situations efficiently and robust. Only a single constraint involving a very small number of degrees of freedom is considered at once leading to a very efficient solution. The treatment of friction is exemplified for the Coulomb model. Special care needs the contact of nodes that are subject to restraints. Together with the aforementioned projection for restraints, a novel efficient solution scheme can be presented. The collision integrator does not influence the critical time step. Hence, the time step can be chosen independently from the underlying time-stepping scheme. The time step may be fixed or time-adaptive. New demands on global collision detection are discussed exemplified by position codes and node-to-segment integration. Numerical examples illustrate convergence and efficiency of the new contact algorithm. Copyright © 2013 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons, Ltd. PMID:23970806

Within-female plasticity in sex allocation is associated with a behavioural polyphenism in house wrens.

PubMed

Bowers, E K; Thompson, C F; Sakaluk, S K

2016-03-01

Sex allocation theory assumes individual plasticity in maternal strategies, but few studies have investigated within-individual changes across environments. In house wrens, differences between nests in the degree of hatching synchrony of eggs represent a behavioural polyphenism in females, and its expression varies with seasonal changes in the environment. Between-nest differences in hatching asynchrony also create different environments for offspring, and sons are more strongly affected than daughters by sibling competition when hatching occurs asynchronously over several days. Here, we examined variation in hatching asynchrony and sex allocation, and its consequences for offspring fitness. The number and condition of fledglings declined seasonally, and the frequency of asynchronous hatching increased. In broods hatched asynchronously, sons, which are over-represented in the earlier-laid eggs, were in better condition than daughters, which are over-represented in the later-laid eggs. Nonetheless, asynchronous broods were more productive later within seasons. The proportion of sons in asynchronous broods increased seasonally, whereas there was a seasonal increase in the production of daughters by mothers hatching their eggs synchronously, which was characterized by within-female changes in offspring sex and not by sex-biased mortality. As adults, sons from asynchronous broods were in better condition and produced more broods of their own than males from synchronous broods, and both males and females from asynchronous broods had higher lifetime reproductive success than those from synchronous broods. In conclusion, hatching patterns are under maternal control, representing distinct strategies for allocating offspring within broods, and are associated with offspring sex ratios and differences in offspring reproductive success. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Five-Axis Goniometric Stage

DTIC Science & Technology

2011-02-01

PS4 , Anaheim Automation PSAM24V2.7A) and a custom built variable 24 VDC 5 A power supply (PS5). The input voltage to the variable power supply is...provide power for the four brushless DC motor controllers (Anaheim Automation, MDC050-050051). PS4 supplies power to the optional position sensors...blue) X R15 - (green) 21 R14 + (red) Y R14 - (brown) 22 Z P1 P2 P3 P4 P9 P8 P5 PS1 PS2 PS3 PS4 PS5 19 Pending Distribution A

Universal filtered multi-carrier system for asynchronous uplink transmission in optical access network

NASA Astrophysics Data System (ADS)

Kang, Soo-Min; Kim, Chang-Hun; Han, Sang-Kook

2016-02-01

In passive optical network (PON), orthogonal frequency division multiplexing (OFDM) has been studied actively due to its advantages such as high spectra efficiency (SE), dynamic resource allocation in time or frequency domain, and dispersion robustness. However, orthogonal frequency division multiple access (OFDMA)-PON requires tight synchronization among multiple access signals. If not, frequency orthogonality could not be maintained. Also its sidelobe causes inter-channel interference (ICI) to adjacent channel. To prevent ICI caused by high sidelobes, guard band (GB) is usually used which degrades SE. Thus, OFDMA-PON is not suitable for asynchronous uplink transmission in optical access network. In this paper, we propose intensity modulation/direct detection (IM/DD) based universal filtered multi-carrier (UFMC) PON for asynchronous multiple access. The UFMC uses subband filtering to subsets of subcarriers. Since it reduces sidelobe of each subband by applying subband filtering, it could achieve better performance compared to OFDM. For the experimental demonstration, different sample delay was applied to subbands to implement asynchronous transmission condition. As a result, time synchronization robustness of UFMC was verified in asynchronous multiple access system.

On variable hydrostatic transmission for road vehicles, powered by supply of fluid at constant pressure

NASA Technical Reports Server (NTRS)

Magi, M.; Freivald, A.; Andersson, I.; Ericsson, U.

1981-01-01

Various hydrostatic power transmission systems for automotive applications with power supply at constant pressure and unrestricted flow and with a Volvo Flygmotor variable displacement motor as the principal unit were investigated. Two most promising concepts were analyzed in detail and their main components optimized for minimum power loss at the EPA Urban Driving Cycle. The best fuel consumption is less than 10 lit. per 100 kM for a 1542 kG vehicle with a hydrostatic motor and a two speed gear box in series (braking power not recovered). Realistic system pressure affects the fuel consumption just slightly, but the package volume/weight drastically. Back pressure increases losses significantly. Special attention was paid to description of the behavior and modeling of the losses of variable displacement hydrostatic machines.

A sub-microwatt asynchronous level-crossing ADC for biomedical applications.

PubMed

Li, Yongjia; Zhao, Duan; Serdijn, Wouter A

2013-04-01

A continuous-time level-crossing analog-to-digital converter (LC-ADC) for biomedical applications is presented. When compared to uniform-sampling (US) ADCs LC-ADCs generate fewer samples for various sparse biomedical signals. Lower power consumption and reduced design complexity with respect to conventional LC-ADCs are achieved due to: 1) replacing the n-bit digital-to-analog converter (DAC) with a 1-bit DAC; 2) splitting the level-crossing detections; and 3) fixing the comparison window. Designed and implemented in 0.18 μm CMOS technology, the proposed ADC uses a chip area of 220 × 203 μm(2). Operating from a supply voltage of 0.8 V, the ADC consumes 313-582 nW from 5 Hz to 5 kHz and achieves an ENOB up to 7.9 bits.

A Binary Array Asynchronous Sorting Algorithm with Using Petri Nets

NASA Astrophysics Data System (ADS)

Voevoda, A. A.; Romannikov, D. O.

2017-01-01

Nowadays the tasks of computations speed-up and/or their optimization are actual. Among the approaches on how to solve these tasks, a method applying approaches of parallelization and asynchronization to a sorting algorithm is considered in the paper. The sorting methods are ones of elementary methods and they are used in a huge amount of different applications. In the paper, we offer a method of an array sorting that based on a division into a set of independent adjacent pairs of numbers and their parallel and asynchronous comparison. And this one distinguishes the offered method from the traditional sorting algorithms (like quick sorting, merge sorting, insertion sorting and others). The algorithm is implemented with the use of Petri nets, like the most suitable tool for an asynchronous systems description.

Nonlinear rocket motor stability prediction: Limit amplitude, triggering, and mean pressure shifta)

NASA Astrophysics Data System (ADS)

Flandro, Gary A.; Fischbach, Sean R.; Majdalani, Joseph

2007-09-01

High-amplitude pressure oscillations in solid propellant rocket motor combustion chambers display nonlinear effects including: (1) limit cycle behavior in which the fluctuations may dwell for a considerable period of time near their peak amplitude, (2) elevated mean chamber pressure (DC shift), and (3) a triggering amplitude above which pulsing will cause an apparently stable system to transition to violent oscillations. Along with the obvious undesirable vibrations, these features constitute the most damaging impact of combustion instability on system reliability and structural integrity. The physical mechanisms behind these phenomena and their relationship to motor geometry and physical parameters must, therefore, be fully understood if instability is to be avoided in the design process, or if effective corrective measures must be devised during system development. Predictive algorithms now in use have limited ability to characterize the actual time evolution of the oscillations, and they do not supply the motor designer with information regarding peak amplitudes or the associated critical triggering amplitudes. A pivotal missing element is the ability to predict the mean pressure shift; clearly, the designer requires information regarding the maximum chamber pressure that might be experienced during motor operation. In this paper, a comprehensive nonlinear combustion instability model is described that supplies vital information. The central role played by steep-fronted waves is emphasized. The resulting algorithm provides both detailed physical models of nonlinear instability phenomena and the critically needed predictive capability. In particular, the origin of the DC shift is revealed.

A Hybrid LCC-VSC HVDC Transmission System Supplying a Passive Load

NASA Astrophysics Data System (ADS)

Kotb, Omar

High Voltage Direct Current (HVDC) transmission systems continue to be an excellent asset in modern power systems, mainly for their ability to overcome the problems of AC transmission, such as the interconnection of asynchronous grids, stability of long transmission lines, and use of long cables for power transmission. In the past 20 years, Voltage Source Converter (VSC)-HVDC transmission systems were developed and installed in many projects, thereby adding more operational benefits to DC transmission option, such as high controllability, ability to supply weak networks, and reduced converter reactive power demand. Nevertheless, VSC-HVDC transmission suffers from the disadvantages of high losses and cost. In this research, a hybrid HVDC employing a Line Commutated Converter (LCC) as rectifier and a VSC as inverter is used to supply a passive network through a DC cable. The hybrid system is best suited for unidirectional power transmission scenarios, such as power transmission to islands and remote load centers, where the construction of new transmission lines is prohibitively expensive. Control modes for the rectifier and inverter are selected and implemented using Proportional Integral (PI) controllers. Special control schemes are developed for abnormal operating conditions such as starting at light load and recovering from AC network faults. The system performance under steady state and transient conditions is investigated by EMTP-RV simulations. The results show the feasibility of the hybrid system.

Performance of 22.4-kW nonlaminated-frame dc series motor with chopper controller. [a dc to dc voltage converter

NASA Technical Reports Server (NTRS)

Schwab, J. R.

1979-01-01

Performance data obtained through experimental testing of a 22.4 kW traction motor using two types of excitation are presented. Ripple free dc from a motor-generator set for baseline data and pulse width modulated dc as supplied by a battery pack and chopper controller were used for excitation. For the same average values of input voltage and current, the motor power output was independent of the type of excitation. However, at the same speeds, the motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points lower on chopped dc than on ripple free dc. The chopped dc locked-rotor torque was approximately 1 to 3 percent greater than the ripple free dc torque for the same average current.

Force Analysis and Energy Operation of Chaotic System of Permanent-Magnet Synchronous Motor

NASA Astrophysics Data System (ADS)

Qi, Guoyuan; Hu, Jianbing

2017-12-01

The disadvantage of a nondimensionalized model of a permanent-magnet synchronous Motor (PMSM) is identified. The original PMSM model is transformed into a Kolmogorov system to aid dynamic force analysis. The vector field of the PMSM is analogous to the force field including four types of torque — inertial, internal, dissipative, and generalized external. Using the feedback thought, the error torque between external torque and dissipative torque is identified. The pitchfork bifurcation of the PMSM is performed. Four forms of energy are identified for the system — kinetic, potential, dissipative, and supplied. The physical interpretations of the decomposition of force and energy exchange are given. Casimir energy is stored energy, and its rate of change is the error power between the dissipative energy and the energy supplied to the motor. Error torque and error power influence the different types of dynamic modes. The Hamiltonian energy and Casimir energy are compared to find the function of each in producing the dynamic modes. A supremum bound for the chaotic attractor is proposed using the error power and Lagrange multiplier.

Interpolation algorithm for asynchronous ADC-data

NASA Astrophysics Data System (ADS)

Bramburger, Stefan; Zinke, Benny; Killat, Dirk

2017-09-01

This paper presents a modified interpolation algorithm for signals with variable data rate from asynchronous ADCs. The Adaptive weights Conjugate gradient Toeplitz matrix (ACT) algorithm is extended to operate with a continuous data stream. An additional preprocessing of data with constant and linear sections and a weighted overlap of step-by-step into spectral domain transformed signals improve the reconstruction of the asycnhronous ADC signal. The interpolation method can be used if asynchronous ADC data is fed into synchronous digital signal processing.

Performance of a 14.9-kW laminated-frame dc series motor with chopper controller

NASA Technical Reports Server (NTRS)

Schwab, J. R.

1979-01-01

Traction motor using two types of excitation: ripple free dc from a motor generator set for baseline data and chopped dc as supplied by a battery and chopper controller was tested. For the same average values of input voltage and current, the power output was independent of the type of excitation. At the same speeds, motor efficiency at low power output (corresponding to low duty cycle of the controller) was 5 to 10 percentage points less on chopped dc than on ripple-free dc. This illustrates that for chopped waveforms, it is incorrect to calculate input power as the product of average voltage and average current. Locked-rotor torque, no load losses, and magnetic saturation data were so determined.

AC motor controller with 180 degree conductive switches

NASA Technical Reports Server (NTRS)

Oximberg, Carol A. (Inventor)

1995-01-01

An ac motor controller is operated by a modified time-switching scheme where the switches of the inverter are on for electrical-phase-and-rotation intervals of 180.degree. as opposed to the conventional 120.degree.. The motor is provided with three-phase drive windings, a power inverter for power supplied from a dc power source consisting of six switches, and a motor controller which controls the current controlled switches in voltage-fed mode. During full power, each switch is gated continuously for three successive intervals of 60.degree. and modulated for only one of said intervals. Thus, during each 60.degree. interval, the two switches with like signs are on continuously and the switch with the opposite sign is modulated.

Neural control and precision of flight muscle activation in Drosophila.

PubMed

Lehmann, Fritz-Olaf; Bartussek, Jan

2017-01-01

Precision of motor commands is highly relevant in a large context of various locomotor behaviors, including stabilization of body posture, heading control and directed escape responses. While posture stability and heading control in walking and swimming animals benefit from high friction via ground reaction forces and elevated viscosity of water, respectively, flying animals have to cope with comparatively little aerodynamic friction on body and wings. Although low frictional damping in flight is the key to the extraordinary aerial performance and agility of flying birds, bats and insects, it challenges these animals with extraordinary demands on sensory integration and motor precision. Our review focuses on the dynamic precision with which Drosophila activates its flight muscular system during maneuvering flight, considering relevant studies on neural and muscular mechanisms of thoracic propulsion. In particular, we tackle the precision with which flies adjust power output of asynchronous power muscles and synchronous flight control muscles by monitoring muscle calcium and spike timing within the stroke cycle. A substantial proportion of the review is engaged in the significance of visual and proprioceptive feedback loops for wing motion control including sensory integration at the cellular level. We highlight that sensory feedback is the basis for precise heading control and body stability in flies.

Three-phase receiving coil of wireless power transmission system for gastrointestinal robot

NASA Astrophysics Data System (ADS)

Jia, Z. W.; Jiang, T.; Liu, Y.

2017-11-01

Power shortage is the bottleneck for the wide application of gastrointestinal (GI) robot. Owing to the limited volume and free change of orientation of the receiving set in GI trace, the optimal of receiving set is the key point to promote the transmission efficiency of wireless power transmission system. A new type of receiving set, similar to the winding of three-phase asynchronous motor, is presented and compared with the original three-dimensional orthogonal coil. Considering the given volume and the space utilization ratio, the three-phase and the three-orthogonal ones are the parameters which are optimized and compared. Both the transmission efficiency and stability are analyzed and verified by in vitro experiments. Animal experiments show that the new one could provide at least 420 mW power in volume of Φ11 × 13mm with a uniformity of 78.3% for the GI robot.

Brain-computer interface design using alpha wave

NASA Astrophysics Data System (ADS)

Zhao, Hai-bin; Wang, Hong; Liu, Chong; Li, Chun-sheng

2010-01-01

A brain-computer interface (BCI) is a novel communication system that translates brain activity into commands for a computer or other electronic devices. BCI system based on non-invasive scalp electroencephalogram (EEG) has become a hot research area in recent years. BCI technology can help improve the quality of life and restore function for people with severe motor disabilities. In this study, we design a real-time asynchronous BCI system using Alpha wave. The basic theory of this BCI system is alpha wave-block phenomenon. Alpha wave is the most prominent wave in the whole realm of brain activity. This system includes data acquisition, feature selection and classification. The subject can use this system easily and freely choose anyone of four commands with only short-time training. The results of the experiment show that this BCI system has high classification accuracy, and has potential application for clinical engineering and is valuable for further research.

Top-down cortical input during NREM sleep consolidates perceptual memory.

PubMed

Miyamoto, D; Hirai, D; Fung, C C A; Inutsuka, A; Odagawa, M; Suzuki, T; Boehringer, R; Adaikkan, C; Matsubara, C; Matsuki, N; Fukai, T; McHugh, T J; Yamanaka, A; Murayama, M

2016-06-10

During tactile perception, long-range intracortical top-down axonal projections are essential for processing sensory information. Whether these projections regulate sleep-dependent long-term memory consolidation is unknown. We altered top-down inputs from higher-order cortex to sensory cortex during sleep and examined the consolidation of memories acquired earlier during awake texture perception. Mice learned novel textures and consolidated them during sleep. Within the first hour of non-rapid eye movement (NREM) sleep, optogenetic inhibition of top-down projecting axons from secondary motor cortex (M2) to primary somatosensory cortex (S1) impaired sleep-dependent reactivation of S1 neurons and memory consolidation. In NREM sleep and sleep-deprivation states, closed-loop asynchronous or synchronous M2-S1 coactivation, respectively, reduced or prolonged memory retention. Top-down cortical information flow in NREM sleep is thus required for perceptual memory consolidation. Copyright © 2016, American Association for the Advancement of Science.

Achieving the Air Force’s Energy Vision

DTIC Science & Technology

2011-01-01

sor of logistics and supply chain management at AFIT. The US Air Force is the largest con -sumer of energy in the federal gov-ernment, spending $9...technology, motors , advanced bat- teries, and ultracapacitors. AFIT is playing a critical role in meeting Air Force and industry demand for more...Flight Design displayed a parallel hybrid-electric propul- sion system with an ICE and electric motor (fig. 2) for a general aviation aircraft. A

Electromechanical actuator for the tongs of a servomanipulator

DOEpatents

Martin, H. Lee; Killough, Stephen M.

1986-01-01

Computer-augmented electromechanical system is provided for controlling the tongs of a servomanipulator. The mechanical tongs are motor-driven through the remote slave arm of the manipulator, and the motor control current is supplied by a position sensor which senses the position of a spring-loaded trigger in the master arm handle on the manipulator. The actuator for the tongs provides the operator with artificial force reflection in a unilateral force-force control loop.

Study of solid rocket motors for a space shuttle booster, volume 2

NASA Technical Reports Server (NTRS)

1972-01-01

Additional technical data have been prepared to supplement the data supplied in the SRM shuttle booster final report. These data cover performance characteristics utilizing motor efficiencies of 0.960 and 0.947 with nozzle divergence half angles of 15 deg and 20 deg, respectively; PBAN propellant characteristics; parametric data to extend baseline designs to varying states of SRM's; summary of SRM mass properties; and SRM exhaust plume profiles.

Determination of power and moment on shaft of special asynchronous electric drives

NASA Astrophysics Data System (ADS)

Karandey, V. Yu; Popov, B. K.; Popova, O. B.; Afanasyev, V. L.

2018-03-01

In the article, questions and tasks of determination of power and the moment on a shaft of special asynchronous electric drives are considered. Use of special asynchronous electric drives in mechanical engineering and other industries is relevant. The considered types of electric drives possess the improved mass-dimensional indicators in comparison with singleengine systems. Also these types of electric drives have constructive advantages; the improved characteristics allow one to realize the technological process. But creation and design of new electric drives demands adjustment of existing or development of new methods and approaches of calculation of parameters. Determination of power and the moment on a shaft of special asynchronous electric drives is the main objective during design of electric drives. This task has been solved based on a method of electromechanical transformation of energy.

Distributed asynchronous microprocessor architectures in fault tolerant integrated flight systems

NASA Technical Reports Server (NTRS)

Dunn, W. R.

1983-01-01

The paper discusses the implementation of fault tolerant digital flight control and navigation systems for rotorcraft application. It is shown that in implementing fault tolerance at the systems level using advanced LSI/VLSI technology, aircraft physical layout and flight systems requirements tend to define a system architecture of distributed, asynchronous microprocessors in which fault tolerance can be achieved locally through hardware redundancy and/or globally through application of analytical redundancy. The effects of asynchronism on the execution of dynamic flight software is discussed. It is shown that if the asynchronous microprocessors have knowledge of time, these errors can be significantly reduced through appropiate modifications of the flight software. Finally, the papear extends previous work to show that through the combined use of time referencing and stable flight algorithms, individual microprocessors can be configured to autonomously tolerate intermittent faults.

The Design of Finite State Machine for Asynchronous Replication Protocol

NASA Astrophysics Data System (ADS)

Wang, Yanlong; Li, Zhanhuai; Lin, Wei; Hei, Minglei; Hao, Jianhua

Data replication is a key way to design a disaster tolerance system and to achieve reliability and availability. It is difficult for a replication protocol to deal with the diverse and complex environment. This means that data is less well replicated than it ought to be. To reduce data loss and to optimize replication protocols, we (1) present a finite state machine, (2) run it to manage an asynchronous replication protocol and (3) report a simple evaluation of the asynchronous replication protocol based on our state machine. It's proved that our state machine is applicable to guarantee the asynchronous replication protocol running in the proper state to the largest extent in the event of various possible events. It also can helpful to build up replication-based disaster tolerance systems to ensure the business continuity.

Automatic motor task selection via a bandit algorithm for a brain-controlled button

NASA Astrophysics Data System (ADS)

Fruitet, Joan; Carpentier, Alexandra; Munos, Rémi; Clerc, Maureen

2013-02-01

Objective. Brain-computer interfaces (BCIs) based on sensorimotor rhythms use a variety of motor tasks, such as imagining moving the right or left hand, the feet or the tongue. Finding the tasks that yield best performance, specifically to each user, is a time-consuming preliminary phase to a BCI experiment. This study presents a new adaptive procedure to automatically select (online) the most promising motor task for an asynchronous brain-controlled button. Approach. We develop for this purpose an adaptive algorithm UCB-classif based on the stochastic bandit theory and design an EEG experiment to test our method. We compare (offline) the adaptive algorithm to a naïve selection strategy which uses uniformly distributed samples from each task. We also run the adaptive algorithm online to fully validate the approach. Main results. By not wasting time on inefficient tasks, and focusing on the most promising ones, this algorithm results in a faster task selection and a more efficient use of the BCI training session. More precisely, the offline analysis reveals that the use of this algorithm can reduce the time needed to select the most appropriate task by almost half without loss in precision, or alternatively, allow us to investigate twice the number of tasks within a similar time span. Online tests confirm that the method leads to an optimal task selection. Significance. This study is the first one to optimize the task selection phase by an adaptive procedure. By increasing the number of tasks that can be tested in a given time span, the proposed method could contribute to reducing ‘BCI illiteracy’.

The Use of Efficient Broadcast Protocols in Asynchronous Distributed Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Schmuck, Frank Bernhard

1988-01-01

Reliable broadcast protocols are important tools in distributed and fault-tolerant programming. They are useful for sharing information and for maintaining replicated data in a distributed system. However, a wide range of such protocols has been proposed. These protocols differ in their fault tolerance and delivery ordering characteristics. There is a tradeoff between the cost of a broadcast protocol and how much ordering it provides. It is, therefore, desirable to employ protocols that support only a low degree of ordering whenever possible. This dissertation presents techniques for deciding how strongly ordered a protocol is necessary to solve a given application problem. It is shown that there are two distinct classes of application problems: problems that can be solved with efficient, asynchronous protocols, and problems that require global ordering. The concept of a linearization function that maps partially ordered sets of events to totally ordered histories is introduced. How to construct an asynchronous implementation that solves a given problem if a linearization function for it can be found is shown. It is proved that in general the question of whether a problem has an asynchronous solution is undecidable. Hence there exists no general algorithm that would automatically construct a suitable linearization function for a given problem. Therefore, an important subclass of problems that have certain commutativity properties are considered. Techniques for constructing asynchronous implementations for this class are presented. These techniques are useful for constructing efficient asynchronous implementations for a broad range of practical problems.

Digital Self-Interference Cancellation for Asynchronous In-Band Full-Duplex Underwater Acoustic Communication.

PubMed

Qiao, Gang; Gan, Shuwei; Liu, Songzuo; Ma, Lu; Sun, Zongxin

2018-05-24

To improve the throughput of underwater acoustic (UWA) networking, the In-band full-duplex (IBFD) communication is one of the most vital pieces of research. The major drawback of IBFD-UWA communication is Self-Interference (SI). This paper presents a digital SI cancellation algorithm for asynchronous IBFD-UWA communication system. We focus on two issues: one is asynchronous communication dissimilar to IBFD radio communication, the other is nonlinear distortion caused by power amplifier (PA). First, we discuss asynchronous IBFD-UWA signal model with the nonlinear distortion of PA. Then, we design a scheme for asynchronous IBFD-UWA communication utilizing the non-overlapping region between SI and intended signal to estimate the nonlinear SI channel. To cancel the nonlinear distortion caused by PA, we propose an Over-Parameterization based Recursive Least Squares (RLS) algorithm (OPRLS) to estimate the nonlinear SI channel. Furthermore, we present the OPRLS with a sparse constraint to estimate the SI channel, which reduces the requirement of the length of the non-overlapping region. Finally, we verify our concept through simulation and the pool experiment. Results demonstrate that the proposed digital SI cancellation scheme can cancel SI efficiently.

A massively asynchronous, parallel brain.

PubMed

Zeki, Semir

2015-05-19

Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously--with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain.

Spinal Accessory Motor Neurons in the Mouse: A Special Type of Branchial Motor Neuron?

PubMed

Watson, Charles; Tvrdik, Petr

2018-04-16

The spinal accessory nerve arises from motor neurons in the upper cervical spinal cord. The axons of these motor neurons exit dorsal to the ligamentum denticulatum and form the spinal accessory nerve. The nerve ascends in the spinal subarachnoid space to enter the posterior cranial fossa through the foramen magnum. The spinal accessory nerve then turns caudally to exit through the jugular foramen alongside the vagus and glossopharyngeal nerves, and then travels to supply the sternomastoid and trapezius muscles in the neck. The unusual course of the spinal accessory nerve has long prompted speculation that it is not a typical spinal motor nerve and that it might represent a caudal remnant of the branchial motor system. Our cell lineage tracing data, combined with images from public databases, show that the spinal accessory motor neurons in the mouse transiently express Phox2b, a transcription factor that is required for development of brain stem branchial motor nuclei. While this is strong prima facie evidence that the spinal accessory motor neurons should be classified as branchial motor, the evolutionary history of these motor neurons in anamniote vertebrates suggests that they may be considered to be an atypical branchial group that possesses both branchial and somatic characteristics. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Scenario Decomposition for 0-1 Stochastic Programs: Improvements and Asynchronous Implementation

DOE PAGES

Ryan, Kevin; Rajan, Deepak; Ahmed, Shabbir

2016-05-01

We recently proposed scenario decomposition algorithm for stochastic 0-1 programs finds an optimal solution by evaluating and removing individual solutions that are discovered by solving scenario subproblems. In our work, we develop an asynchronous, distributed implementation of the algorithm which has computational advantages over existing synchronous implementations of the algorithm. Improvements to both the synchronous and asynchronous algorithm are proposed. We also test the results on well known stochastic 0-1 programs from the SIPLIB test library and is able to solve one previously unsolved instance from the test set.

Finite-time synchronization of uncertain coupled switched neural networks under asynchronous switching.

PubMed

Wu, Yuanyuan; Cao, Jinde; Li, Qingbo; Alsaedi, Ahmed; Alsaadi, Fuad E

2017-01-01

This paper deals with the finite-time synchronization problem for a class of uncertain coupled switched neural networks under asynchronous switching. By constructing appropriate Lyapunov-like functionals and using the average dwell time technique, some sufficient criteria are derived to guarantee the finite-time synchronization of considered uncertain coupled switched neural networks. Meanwhile, the asynchronous switching feedback controller is designed to finite-time synchronize the concerned networks. Finally, two numerical examples are introduced to show the validity of the main results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Control method for peak power delivery with limited DC-bus voltage

DOEpatents

Edwards, John; Xu, Longya; Bhargava, Brij B.

2006-09-05

A method for driving a neutral point-clamped multi-level voltage source inverter supplying a synchronous motor is provided. A DC current is received at a neutral point-clamped multi-level voltage source inverter. The inverter has first, second, and third output nodes. The inverter also has a plurality of switches. A desired speed of a synchronous motor connected to the inverter by the first second and third nodes is received by the inverter. The synchronous motor has a rotor and the speed of the motor is defined by the rotational rate of the rotor. A position of the rotor is sensed, current flowing to the motor out of at least two of the first, second, and third output nodes is sensed, and predetermined switches are automatically activated by the inverter responsive to the sensed rotor position, the sensed current, and the desired speed.

The development and testing of a linear induction motor being fed from the source with limited electric power

NASA Astrophysics Data System (ADS)

Tiunov, V. V.

2018-02-01

The report provides results of the research related to the tubular linear induction motors’ application. The motors’ design features, a calculation model, a description of test specimens for mining and electric power industry are introduced. The most attention is given to the single-phase motors for high voltage switches drives with the usage of inexpensive standard single-phase transformers for motors’ power supply. The method of the motor’s parameters determination, when the motor is being fed from the transformer, working in the overload mode, was described, and the results of it practical usage were good enough for the engineering practice.

PZT Thin Film Piezoelectric Traveling Wave Motor

NASA Technical Reports Server (NTRS)

Shen, Dexin; Zhang, Baoan; Yang, Genqing; Jiao, Jiwei; Lu, Jianguo; Wang, Weiyuan

1995-01-01

With the development of micro-electro-mechanical systems (MEMS), its various applications are attracting more and more attention. Among MEMS, micro motors, electrostatic and electromagnetic, are the typical and important ones. As an alternative approach, the piezoelectric traveling wave micro motor, based on thin film material and integrated circuit technologies, circumvents many of the drawbacks of the above mentioned two types of motors and displays distinct advantages. In this paper we report on a lead-zirconate-titanate (PZT) piezoelectric thin film traveling wave motor. The PZT film with a thickness of 150 micrometers and a diameter of 8 mm was first deposited onto a metal substrate as the stator material. Then, eight sections were patterned to form the stator electrodes. The rotor had an 8 kHz frequency power supply. The rotation speed of the motor is 100 rpm. The relationship of the friction between the stator and the rotor and the structure of the rotor on rotation were also studied.

Mechanical design of translocating motor proteins.

PubMed

Hwang, Wonmuk; Lang, Matthew J

2009-01-01

Translocating motors generate force and move along a biofilament track to achieve diverse functions including gene transcription, translation, intracellular cargo transport, protein degradation, and muscle contraction. Advances in single molecule manipulation experiments, structural biology, and computational analysis are making it possible to consider common mechanical design principles of these diverse families of motors. Here, we propose a mechanical parts list that include track, energy conversion machinery, and moving parts. Energy is supplied not just by burning of a fuel molecule, but there are other sources or sinks of free energy, by binding and release of a fuel or products, or similarly between the motor and the track. Dynamic conformational changes of the motor domain can be regarded as controlling the flow of free energy to and from the surrounding heat reservoir. Multiple motor domains are organized in distinct ways to achieve motility under imposed physical constraints. Transcending amino acid sequence and structure, physically and functionally similar mechanical parts may have evolved as nature's design strategy for these molecular engines.

Mechanical Design of Translocating Motor Proteins

PubMed Central

Lang, Matthew J.

2013-01-01

Translocating motors generate force and move along a biofilament track to achieve diverse functions including gene transcription, translation, intracellular cargo transport, protein degradation, and muscle contraction. Advances in single molecule manipulation experiments, structural biology, and computational analysis are making it possible to consider common mechanical design principles of these diverse families of motors. Here, we propose a mechanical parts list that include track, energy conversion machinery, and moving parts. Energy is supplied not just by burning of a fuel molecule, but there are other sources or sinks of free energy, by binding and release of a fuel or products, or similarly between the motor and the track. Dynamic conformational changes of the motor domain can be regarded as controlling the flow of free energy to and from the surrounding heat reservoir. Multiple motor domains are organized in distinct ways to achieve motility under imposed physical constraints. Transcending amino acid sequence and structure, physically and functionally similar mechanical parts may have evolved as nature’s design strategy for these molecular engines. PMID:19452133

Development status of a 125 horsepower superconducting motor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schiferl, R.F.; Zhang, B.X.; Driscoll, D.I.

1997-06-01

The current development status of an air core synchronous motor with high-temperature superconducting field coils is presented. The work described is part of a U.S. DoE Superconductivity Partnership Initiative award. The motor design features a topology with a combination of a modified conventional armature and a rotating four-pole superconducting field winding operating at a nominal temperature of 27 K. For testing purposes, an open-loop cryogenic system is adopted to supply helium gas to the rotor cryostat for maintaining the operating temperature of the superconducting field winding. The exhaust helium gas intercepts heat leak into the rotor cryostat before being vented.more » The motor is expected to deliver 125 horsepower (hp) at 1,800 rpm. Successful demonstration of the 125 hp motor will represent a major milestone in the process of developing commercial superconducting motors with integrated closed-loop cryogenic systems. Design objectives and results as well as current project status are discussed.« less

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression.

PubMed

Amaya, Ronny; Cancel, Limary M; Tarbell, John M

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle-SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease.

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression

PubMed Central

Amaya, Ronny; Cancel, Limary M.; Tarbell, John M.

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle–SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease. PMID:27846267

PsychVACS: a system for asynchronous telepsychiatry.

PubMed

Odor, Alberto; Yellowlees, Peter; Hilty, Donald; Parish, Michelle Burke; Nafiz, Najia; Iosif, Ana-Maria

2011-05-01

To describe the technical development of an asynchronous telepsychiatry application, the Psychiatric Video Archiving and Communication System. A client-server application was developed in Visual Basic.Net with Microsoft(®) SQL database as the backend. It includes the capability of storing video-recorded psychiatric interviews and manages the workflow of the system with automated messaging. Psychiatric Video Archiving and Communication System has been used to conduct the first ever series of asynchronous telepsychiatry consultations worldwide. A review of the software application and the process as part of this project has led to a number of improvements that are being implemented in the next version, which is being written in Java. This is the first description of the use of video recorded data in an asynchronous telemedicine application. Primary care providers and consulting psychiatrists have found it easy to work with and a valuable resource to increase the availability of psychiatric consultation in remote rural locations.

An improved asynchronous brain interface: making use of the temporal history of the LF-ASD feature vectors

NASA Astrophysics Data System (ADS)

Bashashati, Ali; Mason, Steve; Ward, Rabab K.; Birch, Gary E.

2006-06-01

The low-frequency asynchronous switch design (LF-ASD) has been introduced as a direct brain interface (BI) for asynchronous control applications. Asynchronous interfaces, as opposed to synchronous interfaces, have the advantage of being operational at all times and not only at specific system-defined periods. This paper modifies the LF-ASD design by incorporating into the system more knowledge about the attempted movements. Specifically, the history of feature values extracted from the EEG signal is used to detect a right index finger movement attempt. Using data collected from individuals with high-level spinal cord injuries and able-bodied subjects, it is shown that the error characteristics of the modified design are significantly better than the previous LF-ASD design. The true positive rate percentage increased by up to 15 which corresponds to 50% improvement when the system is operating with false positive rates in the 1-2% range.

Fundamental phenomena on fuel decomposition and boundary layer combustion processes with applications to hybrid rocket motors

NASA Technical Reports Server (NTRS)

Kuo, Kenneth K.; Lu, Y. C.; Chiaverini, Martin J.; Harting, George C.

1994-01-01

An experimental study on the fundamental processes involved in fuel decomposition and boundary layer combustion in hybrid rocket motors is being conducted at the High Pressure Combustion Laboratory of the Pennsylvania State University. This research should provide a useful engineering technology base in the development of hybrid rocket motors as well as a fundamental understanding of the complex processes involved in hybrid propulsion. A high pressure slab motor has been designed and manufactured for conducting experimental investigations. Oxidizer (LOX or GOX) supply and control systems have been designed and partly constructed for the head-end injection into the test chamber. Experiments using HTPB fuel, as well as fuels supplied by NASA designated industrial companies will be conducted. Design and construction of fuel casting molds and sample holders have been completed. The portion of these items for industrial company fuel casting will be sent to the McDonnell Douglas Aerospace Corporation in the near future. The study focuses on the following areas: observation of solid fuel burning processes with LOX or GOX, measurement and correlation of solid fuel regression rate with operating conditions, measurement of flame temperature and radical species concentrations, determination of the solid fuel subsurface temperature profile, and utilization of experimental data for validation of a companion theoretical study (Part 2) also being conducted at PSU.

Axons giving rise to the palisade endings of feline extraocular muscles display motor features.

PubMed

Zimmermann, Lars; Morado-Díaz, Camilo J; Davis-López de Carrizosa, María A; de la Cruz, Rosa R; May, Paul J; Streicher, Johannes; Pastor, Ángel M; Blumer, Roland

2013-02-13

Palisade endings are nerve specializations found in the extraocular muscles (EOMs) of mammals, including primates. They have long been postulated to be proprioceptors. It was recently demonstrated that palisade endings are cholinergic and that in monkeys they originate from the EOM motor nuclei. Nevertheless, there is considerable difference of opinion concerning the nature of palisade ending function. Palisade endings in EOMs were examined in cats to test whether they display motor or sensory characteristics. We injected an anterograde tracer into the oculomotor or abducens nuclei and combined tracer visualization with immunohistochemistry and α-bungarotoxin staining. Employing immunohistochemistry, we performed molecular analyses of palisade endings and trigeminal ganglia to determine whether cat palisade endings are a cholinergic trigeminal projection. We confirmed that palisade endings are cholinergic and showed, for the first time, that they, like extraocular motoneurons, are also immunoreactive for calcitonin gene-related peptide. Following tracer injection into the EOM nuclei, we observed tracer-positive palisade endings that exhibited choline acetyl transferase immunoreactivity. The tracer-positive nerve fibers supplying palisade endings also established motor terminals along the muscle fibers, as demonstrated by α-bungarotoxin. Neither the trigeminal ganglion nor the ophthalmic branch of the trigeminal nerve contained cholinergic elements. This study confirms that palisade endings originate in the EOM motor nuclei and further indicates that they are extensions of the axons supplying the muscle fiber related to the palisade. The present work excludes the possibility that they receive cholinergic trigeminal projections. These findings call into doubt the proposed proprioceptive function of palisade endings.

Axons Giving Rise to the Palisade Endings of Feline Extraocular Muscles Display Motor Features

PubMed Central

Zimmermann, Lars; Morado-Díaz, Camilo J.; de Carrizosa, María A. Davis-López; de la Cruz, Rosa R.; May, Paul J.; Streicher, Johannes; Pastor, Ángel M.; Blumer, Roland

2016-01-01

Palisade endings are nerve specializations found in the extraocular muscles (EOMs) of mammals, including primates. They have long been postulated to be proprioceptors. It was recently demonstrated that palisade endings are cholinergic and that in monkeys they originate from the EOM motor nuclei. Nevertheless, there is considerable difference of opinion concerning the nature of palisade ending function. Palisade endings in EOMs were examined in cats to test whether they display motor or sensory characteristics. We injected an anterograde tracer into the oculomotor or abducens nuclei and combined tracer visualization with immunohistochemistry and α-bungarotoxin staining. Employing immunohistochemistry, we performed molecular analyses of palisade endings and trigeminal ganglia to determine whether cat palisade endings are a cholinergic trigeminal projection. We confirmed that palisade endings are cholinergic and showed, for the first time, that they, like extraocular motoneurons, are also immunoreactive for calcitonin gene-related peptide. Following tracer injection into the EOM nuclei, we observed tracer-positive palisade endings that exhibited choline acetyl transferase immunoreactivity. The tracer-positive nerve fibers supplying palisade endings also established motor terminals along the muscle fibers, as demonstrated by α-bungarotoxin. Neither the trigeminal ganglion nor the ophthalmic branch of the trigeminal nerve contained cholinergic elements. This study confirms that palisade endings originate in the EOM motor nuclei and further indicates that they are extensions of the axons supplying the muscle fiber related to the palisade. The present work excludes the possibility that they receive cholinergic trigeminal projections. These findings call into doubt the proposed proprioceptive function of palisade endings. PMID:23407938

Inertial piezoelectric linear motor driven by a single-phase harmonic wave with automatic clamping mechanism

NASA Astrophysics Data System (ADS)

He, Liangguo; Chu, Yuheng; Hao, Sai; Zhao, Xiaoyong; Dong, Yuge; Wang, Yong

2018-05-01

A novel, single-phase, harmonic-driven, inertial piezoelectric linear motor using an automatic clamping mechanism was designed, fabricated, and tested to reduce the sliding friction and simplify the drive mechanism and power supply control of the inertial motor. A piezoelectric bimorph and a flexible hinge were connected in series to form the automatic clamping mechanism. The automatic clamping mechanism was used as the driving and clamping elements. A dynamic simulation by Simulink was performed to prove the feasibility of the motor. The finite element method software COMSOL was used to design the structure of the motor. An experimental setup was built to validate the working principle and evaluate the performance of the motor. The prototype motor outputted a no-load velocity of 3.178 mm/s at a voltage of 220 Vp-p and a maximum traction force of 4.25 N under a preload force of 8 N. The minimum resolution of 1.14 μm was achieved at a driving frequency of 74 Hz, a driving voltage of 50 Vp-p, and a preload force of 0 N.

Nanomotor dynamics in a chemically oscillating medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robertson, Bryan, E-mail: bryan.robertson@mail.utoronto.ca; Kapral, Raymond, E-mail: rkapral@chem.utoronto.ca

2015-04-21

Synthetic nanomotors powered by chemical reactions have potential uses as cargo transport vehicles in both in vivo and in vitro applications. In many situations, motors will have to operate in out-of-equilibrium complex chemically reacting media, which supply fuel to the motors and remove the products they produce. Using molecular simulation and mean-field theory, this paper describes some of the new features that arise when a chemically powered nanomotor, operating through a diffusiophoretic mechanism, moves in an environment that supports an oscillatory chemical reaction network. It is shown how oscillations in the concentrations in chemical species in the environment give risemore » to oscillatory motor dynamics. More importantly, since the catalytic reactions on the motor that are responsible for its propulsion couple to the bulk phase reaction network, the motor can change its local environment. This process can give rise to distinctive spatiotemporal structures in reaction-diffusion media that occur as a result of active motor motion. Such locally induced nonequilibrium structure will play an important role in applications that involve motor dynamics in complex chemical media.« less

77 FR 46024 - Foreign-Trade Zone 8-Toledo, OH; Notification of Proposed Production Activity, Whirlpool...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-02

..., AC motors, power supplies, heater tubs, LED light assemblies, triple level and push button switches, control panels, printed circuit boards, power cords, wire harnesses, EMI filters, pressure sensors...

Analytical and experimental study of high phase order induction motors

NASA Technical Reports Server (NTRS)

Klingshirn, Eugene A.

1989-01-01

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.

Nonpolluting automobiles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoolboom, G.J.; Szabados, B.

The advantages/disadvantages of energy storage devices, which can provide nonpolluting automobile systems are discussed. Four types of storage devices are identified: electrochemical (batteries); hydrogen; electromechanical (flywheels); and molten salt heat storage. A high-speed flywheel with a small permanent magnet motor/generator has more advantages than any of the other systems and might become a real competitor to the internal combustion engine. A flywheel/motor/generator system for automobiles now becomes practical, because of the technological advances in materials, bearings and solid state control circuits. The motor of choice is the squirrel cage induction motor, specially designed for automobile applications. The preferred controller formore » the induction motor is a forced commutated cycloconverter, which transforms a variable voltage/variable frequency source into a controlled variable-voltage/variable-frequency supply. A modulation strategy of the cycloconverter elements is selected to maintain a unity input displacement factor (power factor) under all conditions of loads voltages and frequencies. The system is similar to that of the existing automobile, if only one motor is used: master controller-controller-motor-gears (fixed)-differential-wheels. In the case of two motors, the mechanical differential is replaced by an electric one: master controller-controller-motor-gears (fixed)-wheel. A four-wheel drive vehicle is obtained when four motors with their own controllers are used. 24 refs.« less

A Communication Perspective on Sexual Harassment: Affiliative Nonverbal Behaviors in Asynchronous Relationships.

ERIC Educational Resources Information Center

Hickson, Mark, III; And Others

1991-01-01

Develops a communication perspective on sexual harassment in asynchronous relationships. Presents a six-step process model to predict private harassing behavior among faculty members in higher education. Makes suggestions for prevention of sexual harassment. (SR)

Design and Optimization of an EEG-Based Brain Machine Interface (BMI) to an Upper-Limb Exoskeleton for Stroke Survivors

PubMed Central

Bhagat, Nikunj A.; Venkatakrishnan, Anusha; Abibullaev, Berdakh; Artz, Edward J.; Yozbatiran, Nuray; Blank, Amy A.; French, James; Karmonik, Christof; Grossman, Robert G.; O'Malley, Marcia K.; Francisco, Gerard E.; Contreras-Vidal, Jose L.

2016-01-01

This study demonstrates the feasibility of detecting motor intent from brain activity of chronic stroke patients using an asynchronous electroencephalography (EEG)-based brain machine interface (BMI). Intent was inferred from movement related cortical potentials (MRCPs) measured over an optimized set of EEG electrodes. Successful intent detection triggered the motion of an upper-limb exoskeleton (MAHI Exo-II), to guide movement and to encourage active user participation by providing instantaneous sensory feedback. Several BMI design features were optimized to increase system performance in the presence of single-trial variability of MRCPs in the injured brain: (1) an adaptive time window was used for extracting features during BMI calibration; (2) training data from two consecutive days were pooled for BMI calibration to increase robustness to handle the day-to-day variations typical of EEG, and (3) BMI predictions were gated by residual electromyography (EMG) activity from the impaired arm, to reduce the number of false positives. This patient-specific BMI calibration approach can accommodate a broad spectrum of stroke patients with diverse motor capabilities. Following BMI optimization on day 3, testing of the closed-loop BMI-MAHI exoskeleton, on 4th and 5th days of the study, showed consistent BMI performance with overall mean true positive rate (TPR) = 62.7 ± 21.4% on day 4 and 67.1 ± 14.6% on day 5. The overall false positive rate (FPR) across subjects was 27.74 ± 37.46% on day 4 and 27.5 ± 35.64% on day 5; however for two subjects who had residual motor function and could benefit from the EMG-gated BMI, the mean FPR was quite low (< 10%). On average, motor intent was detected −367 ± 328 ms before movement onset during closed-loop operation. These findings provide evidence that closed-loop EEG-based BMI for stroke patients can be designed and optimized to perform well across multiple days without system recalibration. PMID:27065787

Student Satisfaction with Asynchronous Learning

ERIC Educational Resources Information Center

Dziuban, Charles; Moskal, Patsy; Brophy, Jay; Shea, Peter

2007-01-01

The authors discuss elements that potentially impact student satisfaction with asynchronous learning: the media culture, digital, personal and mobile technologies, student learning preferences, pedagogy, complexities of measurement, and the digital generation. They describe a pilot study to identify the underlying dimensions of student…

An exploration of teaching presence in online interprofessional education facilitation.

PubMed

Evans, Sherryn Maree; Ward, Catherine; Reeves, Scott

2017-07-01

Although the prevalence of online asynchronous interprofessional education (IPE) has increased in the last decade, little is known about the processes of facilitation in this environment. The teaching presence element of the Community of Inquiry Framework offers an approach to analyze the contributions of online facilitators, however, to date it has only been used on a limited basis in health professions education literature. Using an exploratory case study design, we explored the types of contributions made by IPE facilitators to asynchronous interprofessional team discussions by applying the notion of teaching presence. Using a purposeful sampling approach, we analyzed 14 facilitators' contributions to asynchronous team discussion boards in an online IPE course. We analyzed data using directed content analysis based on the key indicators of teaching presence. The online IPE facilitators undertook the three critical pedagogical functions identified in teaching presence: facilitating discourse, direct instruction, and instructional design and organization. While our data fitted well with a number of key activities embedded in these three functions, further modification of the teaching presence concept was needed to describe our facilitators' teaching presence. This study provides an initial insight into the key elements of online asynchronous IPE facilitation. Further research is required to continue to illuminate the complexity of online asynchronous IPE facilitation.

Asynchronous P300 classification in a reactive brain-computer interface during an outlier detection task

NASA Astrophysics Data System (ADS)

Krumpe, Tanja; Walter, Carina; Rosenstiel, Wolfgang; Spüler, Martin

2016-08-01

Objective. In this study, the feasibility of detecting a P300 via an asynchronous classification mode in a reactive EEG-based brain-computer interface (BCI) was evaluated. The P300 is one of the most popular BCI control signals and therefore used in many applications, mostly for active communication purposes (e.g. P300 speller). As the majority of all systems work with a stimulus-locked mode of classification (synchronous), the field of applications is limited. A new approach needs to be applied in a setting in which a stimulus-locked classification cannot be used due to the fact that the presented stimuli cannot be controlled or predicted by the system. Approach. A continuous observation task requiring the detection of outliers was implemented to test such an approach. The study was divided into an offline and an online part. Main results. Both parts of the study revealed that an asynchronous detection of the P300 can successfully be used to detect single events with high specificity. It also revealed that no significant difference in performance was found between the synchronous and the asynchronous approach. Significance. The results encourage the use of an asynchronous classification approach in suitable applications without a potential loss in performance.

A Passive EMI Filter with Access to the Ungrounded Motor Neutral Line-Its Effect on Eliminating Leakage Current from the Inverter Heat Sink-

NASA Astrophysics Data System (ADS)

Doumoto, Takafumi; Akagi, Hirofumi

This paper deals with a leakage current flowing out of the heat sink of a voltage-source PWM inverter. The heat-sink leakage current is caused by a steep change in the common-mode voltage produced by the inverter. It flows through parasitic capacitors between the heat sink and power semiconductor devices when no EMI filter is connected. Experimental results reveal that the heat-sink leakage current flows not into the supply side, but into the motor side. These understandings succeed in describing an equivalent common-mode circuit taking the parasitic capacitors into account. The authors have proposed a passive EMI filter that is unique in access to the ungrounded motor neutral line. It is discussed from this equivalent circuit that the passive EMI filter is effective in preventing the leakage current from flowing. Moreover, installation of another small-sized common-mode inductor at the ac side of the diode rectifier prevents the leakage current from flowing into the supply side. Experimental results obtained from a 200-V, 3.7-kW laboratory system confirm the effectiveness and viability of the EMI filter.

Steady-state analysis of a faulted three-phase four-wire system supplying induction motors with neutrals connected and other single-phase line-to-neutral loads

NASA Technical Reports Server (NTRS)

Wood, M. E.

1980-01-01

Four wire Wye connected ac power systems exhibit peculiar steady state fault characteristics when the fourth wire of three phase induction motors is connected. The loss of one phase of power source due to a series or shunt fault results in currents higher than anticipated on the remaining two phases. A theoretical approach to compute the fault currents and voltages is developed. A FORTRAN program is included in the appendix.

Study of Increasing Lead Times in Major Weapon Systems Acquisition.

DTIC Science & Technology

1982-07-31

Conduit Covers X X X Connectors, Electrical X X X X X Control Systems (Auto- mated, Boiler) X Davit, Boat, Power- Opera.ted X Diodes X X X X A iX...tubes. Other end uses include washers in computer equipment, electrical insulators in motors and generators, and retardation plates in lasers . Supply...relays, electron tubes, printed circuits, and resistors. Platinum is also used in dentistry and for jewelry. Supply, A small amount of platinum (less

Design and develop speed/pressure regulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasanul Basher, A.M.

1993-09-01

The Physics Division at Oak Ridge National Laboratory has several recirculating water cooling systems. One of them supplies deionized water at 150 psi, which is mainly used for cooling magnet windings at the Oak Ridge Isochronous Cyclotron (ORIC). The system has three 125-hp water pumps, each of which is capable of supplying water at the rate of 1000 gpm. One of the major requirements of this water supply system is that the supply pressure must be kept constant. An adjustable-frequency speed controller was recently installed to control the speed of one of the pump motors. A servo-system was provided withmore » the adjustable-frequency controller for regulating motor speed and, subsequently, the water pressure. After unsuccessful attempts to operate the servo, it was concluded that the regulator may not work for the existing system. Prior to installation of the variable-frequency controller, pressure regulation was accomplished with a pneumatically controlled load by-pass valve. To maintain constant pressure in the system, it is necessary to run always at full load, even if full load is not on the system. Hence, there is a waste of energy when full load is not connected to the system. So, designing and implementing one regulator that works at any load condition has become necessary. This report discusses the design of such a pressure regulator.« less

Insect Seed Predators in Erythrina falcata (Fabaceae): Identification of Predatory Species and Ecological Consequences of Asynchronous Flowering.

PubMed

Pereira, C M; Moura, M O; Da-Silva, P R

2014-06-01

Seed predation by insects exerts negative effects on plant reproduction by limiting the supply of seeds and preventing germination. Seed predators of the family Fabaceae are usually generalists, which increases the rate of predation. One strategy to minimize seed predation, developed by plants from temperate regions, is "escape in time," i.e., flowering before or after the peak of predation. For tropical species, few studies have investigated the strategies used by plants to minimize seed predation. Here, using Erythrina falcata, a tropical species of Fabaceae, we test three main hypotheses: (i) escape in time is a mechanism used by E. falcata to minimize seed predation, (ii) the predators of E. falcata seeds are generalists, and (iii) the biometric variables of the pods can influence seed predation. In order to test these hypotheses, we determined the flowering time of E. falcata, rate of seed predation, the predators insects, and biometric variables of the pods. The analyzed trees were grouped into three classes: "early," "peak," and "late" flowering. The average seed predation rates on trees in the early and late classes were 65% and 50%, respectively, and in the peak class, 80%; thus, our first hypothesis can be accepted. Three species of Lepidoptera and two of Coleoptera were found preying on E. falcata seeds. These species were observed to be generalist predators; thus, our second hypothesis can be accepted. The biometric variables of the pods cannot influence seed predation rate. The ecological consequences of asynchronous flowering on plants and insects are discussed.

Learning Objects and Gerontology

ERIC Educational Resources Information Center

Weinreich, Donna M.; Tompkins, Catherine J.

2006-01-01

Virtual AGE (vAGE) is an asynchronous educational environment that utilizes learning objects focused on gerontology and a learning anytime/anywhere philosophy. This paper discusses the benefits of asynchronous instruction and the process of creating learning objects. Learning objects are "small, reusable chunks of instructional media" Wiley…

Redundant Asynchronous Microprocessor System

NASA Technical Reports Server (NTRS)

Meyer, G.; Johnston, J. O.; Dunn, W. R.

1985-01-01

Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

Hypnosis in sport: an Isomorphic Model.

PubMed

Robazza, C; Bortoli, L

1994-10-01

Hypnosis in sport can be applied according to an Isomorphic Model. Active-alert hypnosis is induced before or during practice whereas traditional hypnosis is induced after practice to establish connections between the two experiences. The fundamental goals are to (a) develop mental skills important to both motor and hypnotic performance, (b) supply a wide range of motor and hypnotic bodily experiences important to performance, and (c) induce alert hypnosis before or during performance. The model is based on the assumption that hypnosis and motor performance share common skills modifiable through training. Similarities between hypnosis and peak performance in the model are also considered. Some predictions are important from theoretical and practical points of view.

Field-Oriented Control Of Induction Motors

NASA Technical Reports Server (NTRS)

Burrows, Linda M.; Roth, Mary Ellen; Zinger, Don S.

1993-01-01

Field-oriented control system provides for feedback control of torque or speed or both. Developed for use with commercial three-phase, 400-Hz, 208-V, 5-hp motor. Systems include resonant power supply operating at 20 kHz. Pulse-population-modulation subsystem selects individual pulses of 20-kHz single-phase waveform as needed to synthesize three waveforms of appropriate lower frequency applied to three phase windings of motor. Electric actuation systems using technology currently being built to peak powers of 70 kW. Amplitude of voltage of effective machine-frequency waveform determined by momentary frequency of pulses, while machine frequency determined by rate of repetition of overall temporal pattern of pulses. System enables independent control of both voltage and frequency.

Performance Analysis of Three-Phase Induction Motor with AC Direct and VFD

NASA Astrophysics Data System (ADS)

Kumar, Dinesh

2018-03-01

The electrical machine analysis and performance calculation is a very important aspect of efficient drive system design. The development of power electronics devices and power converters provide smooth speed control of Induction Motors by changing the frequency of input supply. These converters, on one hand are providing a more flexible speed control that also leads to problems of harmonics and their associated ailments like pulsating torque, distorted current and voltage waveforms, increasing losses etc. This paper includes the performance analysis of three phase induction motor with three-phase AC direct and variable frequency drives (VFD). The comparison has been concluded with respect to various parameters. MATLAB-SIMULINKTM is used for the analysis.

A comparison of classroom and online asynchronous problem-based learning for students undertaking statistics training as part of a Public Health Masters degree.

PubMed

de Jong, N; Verstegen, D M L; Tan, F E S; O'Connor, S J

2013-05-01

This case-study compared traditional, face-to-face classroom-based teaching with asynchronous online learning and teaching methods in two sets of students undertaking a problem-based learning module in the multilevel and exploratory factor analysis of longitudinal data as part of a Masters degree in Public Health at Maastricht University. Students were allocated to one of the two study variants on the basis of their enrolment status as full-time or part-time students. Full-time students (n = 11) followed the classroom-based variant and part-time students (n = 12) followed the online asynchronous variant which included video recorded lectures and a series of asynchronous online group or individual SPSS activities with synchronous tutor feedback. A validated student motivation questionnaire was administered to both groups of students at the start of the study and a second questionnaire was administered at the end of the module. This elicited data about student satisfaction with the module content, teaching and learning methods, and tutor feedback. The module coordinator and problem-based learning tutor were also interviewed about their experience of delivering the experimental online variant and asked to evaluate its success in relation to student attainment of the module's learning outcomes. Student examination results were also compared between the two groups. Asynchronous online teaching and learning methods proved to be an acceptable alternative to classroom-based teaching for both students and staff. Educational outcomes were similar for both groups, but importantly, there was no evidence that the asynchronous online delivery of module content disadvantaged part-time students in comparison to their full-time counterparts.

Magnification of starting torques of dc motors by maximum power point trackers in photovoltaic systems

NASA Technical Reports Server (NTRS)

Appelbaum, Joseph; Singer, S.

1989-01-01

Direct current (dc) motors are used in terrestrial photovoltaic (PV) systems such as in water-pumping systems for irrigation and water supply. Direct current motors may also be used for space applications. Simple and low weight systems including dc motors may be of special interest in space where the motors are directly coupled to the solar cell array (with no storage). The system will operate only during times when sufficient insolation is available. An important performance characteristic of electric motors is the starting to rated torque ratio. Different types of dc motors have different starting torque ratios. These ratios are dictated by the size of solar cell array, and the developed motor torque may not be sufficient to overcome the load starting torque. By including a maximum power point tracker (MPPT) in the PV system, the starting to rated torque ratio will increase, the amount of which depends on the motor type. The starting torque ratio is calculated for the permanent magnet, series and shunt excited dc motors when powered by solar cell arrays for two cases: with and without MPPT's. Defining a motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 was obtained for the permanent magnet motor and a magnification of 7 for both the series and shunt motors. The effect of the variation of solar insolation on the motor starting torque was covered. All motor types are less sensitive to insolation variation in systems including MPPT's as compared to systems with MPPT's. The analysis of this paper will assist the PV system designed to determine whether or not to include an MPPT in the system for a specific motor type.

Assessing Energy Efficiency Opportunities in US Industrial and Commercial Building Motor Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rao, Prakash; Sheaffer, Paul; McKane, Aimee

2015-09-01

In 2002, the United States Department of Energy (USDOE) published an energy efficiency assessment of U.S. industrial sector motor systems titled United States Industrial Electric Motor Systems Market Opportunities Assessment. The assessment advanced motor system efficiency by providing a greater understanding of the energy consumption, use characteristics, and energy efficiency improvement potential of industrial sector motor systems in the U.S. Since 2002, regulations such as Minimum Energy Performance Standards, cost reductions for motor system components such as variable frequency drives, system-integrated motor-driven equipment, and awareness programs for motor system energy efficiency have changed the landscape of U.S. motor system energymore » consumption. To capture the new landscape, the USDOE has initiated a three-year Motor System Market Assessment (MSMA), led by Lawrence Berkeley National Laboratory (LBNL). The MSMA will assess the energy consumption, operational and maintenance characteristics, and efficiency improvement opportunity of U.S. industrial sector and commercial building motor systems. As part of the MSMA, a significant effort is currently underway to conduct field assessments of motor systems from a sample of facilities representative of U.S. commercial and industrial motor system energy consumption. The Field Assessment Plan used for these assessments builds on recent LBNL research presented at EEMODS 2011 and EEMODS 2013 using methods for characterizing and determining regional motor system energy efficiency opportunities. This paper provides an update on the development and progress of the MSMA, focusing on the Field Assessment Plan and the framework for assessing the global supply chain for emerging motors and drive technologies.« less

Electric converters of electromagnetic strike machine with capacitor supply

NASA Astrophysics Data System (ADS)

Usanov, K. M.; Volgin, A. V.; Kargin, V. A.; Moiseev, A. P.; Chetverikov, E. A.

2018-03-01

The application of pulse linear electromagnetic engines in small power strike machines (energy impact is 0.01...1.0 kJ), where the characteristic mode of rare beats (pulse seismic vibrator, the arch crash device bins bulk materials), is quite effective. At the same time, the technical and economic performance of such machines is largely determined by the ability of the power source to provide a large instantaneous power of the supply pulses in the winding of the linear electromagnetic motor. The use of intermediate energy storage devices in power systems of rare-shock LEME makes it possible to obtain easily large instantaneous powers, forced energy conversion, and increase the performance of the machine. A capacitor power supply of a pulsed source of seismic waves is proposed for the exploration of shallow depths. The sections of the capacitor storage (CS) are connected to the winding of the linear electromagnetic motor by thyristor dischargers, the sequence of activation of which is determined by the control device. The charge of the capacitors to the required voltage is made directly from the battery source, or through the converter from a battery source with a smaller number of batteries.

Innovative Methods for Providing Instruction to Distance Students Using Technology.

ERIC Educational Resources Information Center

Pival, Paul R.; Tunon, Johanna

2001-01-01

Examines three innovative methods tried at Nova Southeastern University for providing quality bibliographic instruction to distance students: one synchronous, one asynchronous, and one that combined features from both synchronous and asynchronous methods of delivering instruction. Topics include compressed video, collaborative groupware, streaming…

Miscellany of Students' Satisfaction in an Asynchronous Learning Environment

ERIC Educational Resources Information Center

Larbi-Siaw, Otu; Owusu-Agyeman, Yaw

2017-01-01

This study investigates the determinants of students' satisfaction in an asynchronous learning environment using seven key considerations: the e-learning environment, student-content interaction, student and student interaction, student-teacher interaction, group cohesion and timely participation, knowledge of Internet usage, and satisfaction. The…

20 CFR 416.1220 - Property essential to self-support; general.

Code of Federal Regulations, 2011 CFR

2011-04-01

... and supplies, motor vehicles, and tools, etc.) used in a trade or business (as defined in § 404.1066... activities. Liquid resources other than those used as part of a trade or business are not property essential...

Developing asynchronous online interprofessional education.

PubMed

Sanborn, Heidi

2016-09-01

For many health programmes, developing interprofessional education (IPE) has been a challenge. Evidence on the best method for design and implementation of IPE has been slow to emerge, with little research on how to best incorporate IPE in the asynchronous online learning environment. This leaves online programmes with no clear guidance when embarking upon an initiative to integrate IPE into the curriculum. One tool that can be effective at guiding the incorporation of IPE across all learning platforms is the Interprofessional Education Collaborative (IPEC) competencies. A project was designed to integrate the nationally defined IPEC competencies throughout an asynchronous, online baccalaureate nursing completion programme. A programme-wide review led to targeted revision of course and unit-level objectives, learning experiences, and assessments based on the IPEC framework. As a result of this effort, the programme curriculum now provides interprofessional learning activities across all courses. This report provides a method for using the IPEC competencies to incorporate IPE within various asynchronous learning assessments, assuring students learn about, with, and from other professions.

AP-IO: asynchronous pipeline I/O for hiding periodic output cost in CFD simulation.

PubMed

Xiaoguang, Ren; Xinhai, Xu

2014-01-01

Computational fluid dynamics (CFD) simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO) optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%.

Asynchronous Cholinergic Drive Correlates with Excitation-Inhibition Imbalance via a Neuronal Ca2+ Sensor Protein.

PubMed

Zhou, Keming; Cherra, Salvatore J; Goncharov, Alexandr; Jin, Yishi

2017-05-09

Excitation-inhibition imbalance in neural networks is widely linked to neurological and neuropsychiatric disorders. However, how genetic factors alter neuronal activity, leading to excitation-inhibition imbalance, remains unclear. Here, using the C. elegans locomotor circuit, we examine how altering neuronal activity for varying time periods affects synaptic release pattern and animal behavior. We show that while short-duration activation of excitatory cholinergic neurons elicits a reversible enhancement of presynaptic strength, persistent activation results to asynchronous and reduced cholinergic drive, inducing imbalance between endogenous excitation and inhibition. We find that the neuronal calcium sensor protein NCS-2 is required for asynchronous cholinergic release in an activity-dependent manner and dampens excitability of inhibitory neurons non-cell autonomously. The function of NCS-2 requires its Ca 2+ binding and membrane association domains. These results reveal a synaptic mechanism implicating asynchronous release in regulation of excitation-inhibition balance. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

High-Throughput Bit-Serial LDPC Decoder LSI Based on Multiple-Valued Asynchronous Interleaving

NASA Astrophysics Data System (ADS)

Onizawa, Naoya; Hanyu, Takahiro; Gaudet, Vincent C.

This paper presents a high-throughput bit-serial low-density parity-check (LDPC) decoder that uses an asynchronous interleaver. Since consecutive log-likelihood message values on the interleaver are similar, node computations are continuously performed by using the most recently arrived messages without significantly affecting bit-error rate (BER) performance. In the asynchronous interleaver, each message's arrival rate is based on the delay due to the wire length, so that the decoding throughput is not restricted by the worst-case latency, which results in a higher average rate of computation. Moreover, the use of a multiple-valued data representation makes it possible to multiplex control signals and data from mutual nodes, thus minimizing the number of handshaking steps in the asynchronous interleaver and eliminating the clock signal entirely. As a result, the decoding throughput becomes 1.3 times faster than that of a bit-serial synchronous decoder under a 90nm CMOS technology, at a comparable BER.

AP-IO: Asynchronous Pipeline I/O for Hiding Periodic Output Cost in CFD Simulation

PubMed Central

Xiaoguang, Ren; Xinhai, Xu

2014-01-01

Computational fluid dynamics (CFD) simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO) optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%. PMID:24955390

Asynchronous and synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser with a mode-locker.

PubMed

Hu, Guoqing; Pan, Yingling; Zhao, Xin; Yin, Siyao; Zhang, Meng; Zheng, Zheng

2017-12-01

The evolution from asynchronous to synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser is experimentally investigated by tailoring the intracavity dispersion. Through tuning the intracavity-loss-dependent gain profile and the birefringence-induced filter effect, asynchronous dual-wavelength soliton pulses can be generated until the intracavity anomalous dispersion is reduced to ∼8  fs/nm. The transition from asynchronous to synchronous pulse generation is then observed at an elevated pump power in the presence of residual anomalous dispersion, and it is shown that pulses are temporally synchronized at the mode-locker in the cavity. Spectral sidelobes are observed and could be attributed to the four-wave-mixing effect between dual-wavelength pulses at the carbon nanotube mode-locker. These results could provide further insight into the design and realization of such dual-wavelength ultrafast lasers for different applications such as dual-comb metrology as well as better understanding of the inter-pulse interactions in such dual-comb lasers.

Design and Evaluation of a new mechatronic platform for assessment and prevention of fall risks

PubMed Central

2012-01-01

Background Studying the responses in human behaviour to external perturbations during daily motor tasks is of key importance for understanding mechanisms of balance control and for investigating the functional response of targeted subjects. Experimental platforms as far developed entail a low number of perturbations and, only in few cases, have been designed to measure variables used at run time to trigger events during a certain motor task. Methods This work introduces a new mechatronic device, named SENLY, that provides balance perturbations while subjects carry out daily motor tasks (e.g., walking, upright stance). SENLY mainly consists of two independently-controlled treadmills that destabilize balance by suddenly perturbing belts movements in the horizontal plane. It is also provided with force sensors, which can be used at run time to estimate the ground reaction forces and identify events along the gait cycle in order to trigger the platform perturbation. The paper also describes the customized procedures adopted to calibrate the platform and the first testing trials aimed at evaluating its performance. Results SENLY allows to measure both vertical ground reaction forces and their related location more precisely and more accurately than other platforms of the same size. Moreover, the platform kinematic and kinetic performance meets all required specifications, with a negligible influence of the instrumental noise. Conclusion A new perturbing platform able to reproduce different slipping paradigms while measuring GRFs at run time in order to enable the asynchronous triggering during the gait cycle was designed and developed. Calibration procedures and pilot tests show that SENLY allows to suitably estimate dynamical features of the load and to standardize experimental sessions, improving the efficacy of functional analysis. PMID:22838638

Altered cerebral hemodyamics and cortical thinning in asymptomatic carotid artery stenosis.

PubMed

Marshall, Randolph S; Asllani, Iris; Pavol, Marykay A; Cheung, Ying-Kuen; Lazar, Ronald M

2017-01-01

Cortical thinning is a potentially important biomarker, but the pathophysiology in cerebrovascular disease is unknown. We investigated the association between regional cortical blood flow and regional cortical thickness in patients with asymptomatic unilateral high-grade internal carotid artery disease without stroke. Twenty-nine patients underwent high resolution anatomical and single-delay, pseudocontinuous arterial spin labeling magnetic resonance imaging with partial volume correction to assess gray matter baseline flow. Cortical thickness was estimated using Freesurfer software, followed by co-registration onto each patient's cerebral blood flow image space. Paired t-tests assessed regional cerebral blood flow in motor cortex (supplied by the carotid artery) and visual cortex (indirectly supplied by the carotid) on the occluded and unoccluded side. Pearson correlations were calculated between cortical thickness and regional cerebral blood flow, along with age, hypertension, diabetes and white matter hyperintensity volume. Multiple regression and generalized estimating equation were used to predict cortical thickness bilaterally and in each hemisphere separately. Cortical blood flow correlated with thickness in motor cortex bilaterally (p = 0.0002), and in the occluded and unoccluded sides individually; age (p = 0.002) was also a predictor of cortical thickness in the motor cortex. None of the variables predicted cortical thickness in visual cortex. Blood flow was significantly lower on the occluded versus unoccluded side in the motor cortex (p<0.0001) and in the visual cortex (p = 0.018). On average, cortex was thinner on the side of occlusion in motor but not in visual cortex. The association between cortical blood flow and cortical thickness in carotid arterial territory with greater thinning on the side of the carotid occlusion suggests that altered cerebral hemodynamics is a factor in cortical thinning.

Latent variable method for automatic adaptation to background states in motor imagery BCI

NASA Astrophysics Data System (ADS)

Dagaev, Nikolay; Volkova, Ksenia; Ossadtchi, Alexei

2018-02-01

Objective. Brain-computer interface (BCI) systems are known to be vulnerable to variabilities in background states of a user. Usually, no detailed information on these states is available even during the training stage. Thus there is a need in a method which is capable of taking background states into account in an unsupervised way. Approach. We propose a latent variable method that is based on a probabilistic model with a discrete latent variable. In order to estimate the model’s parameters, we suggest to use the expectation maximization algorithm. The proposed method is aimed at assessing characteristics of background states without any corresponding data labeling. In the context of asynchronous motor imagery paradigm, we applied this method to the real data from twelve able-bodied subjects with open/closed eyes serving as background states. Main results. We found that the latent variable method improved classification of target states compared to the baseline method (in seven of twelve subjects). In addition, we found that our method was also capable of background states recognition (in six of twelve subjects). Significance. Without any supervised information on background states, the latent variable method provides a way to improve classification in BCI by taking background states into account at the training stage and then by making decisions on target states weighted by posterior probabilities of background states at the prediction stage.

Robust Encoding of Spatial Information in Orbitofrontal Cortex and Striatum.

PubMed

Yoo, Seng Bum Michael; Sleezer, Brianna J; Hayden, Benjamin Y

2018-06-01

Knowing whether core reward regions carry information about the positions of relevant objects is crucial for adjudicating between choice models. One limitation of previous studies, including our own, is that spatial positions can be consistently differentially associated with rewards, and thus position can be confounded with attention, motor plans, or target identity. We circumvented these problems by using a task in which value-and thus choices-was determined solely by a frequently changing rule, which was randomized relative to spatial position on each trial. We presented offers asynchronously, which allowed us to control for reward expectation, spatial attention, and motor plans in our analyses. We find robust encoding of the spatial position of both offers and choices in two core reward regions, orbitofrontal Area 13 and ventral striatum, as well as in dorsal striatum of macaques. The trial-by-trial correlation in noise in encoding of position was associated with variation in choice, an effect known as choice probability correlation, suggesting that the spatial encoding is associated with choice and is not incidental to it. Spatial information and reward information are not carried by separate sets of neurons, although the two forms of information are temporally dissociable. These results highlight the ubiquity of multiplexed information in association cortex and argue against the idea that these ostensible reward regions serve as part of a pure value domain.

Electromechanical systems with transient high power response operating from a resonant AC link

NASA Technical Reports Server (NTRS)

Burrows, Linda M.; Hansen, Irving G.

1992-01-01

The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant AC link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control in all four operating quadrants. Incorporating the AC link allows the converter in these systems to switch at the zero crossing of every half cycle of the AC waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed by LeRC and General Dynamics Space Systems Division under contract to NASA. A description of a single motor, electromechanical actuation system is presented. Then, focus is on a conceptual design for an AC electric vehicle. This design incorporates an induction motor/generator together with a flywheel for peak energy storage. System operation and implications along with the associated circuitry are addressed. Such a system would greatly improve all-electric vehicle ranges over the Federal Urban Driving Cycle (FUD).

Asynchronous updates can promote the evolution of cooperation on multiplex networks

NASA Astrophysics Data System (ADS)

Allen, James M.; Hoyle, Rebecca B.

2017-04-01

We study the importance to the frequency of cooperation of the choice of updating strategies in a game played asynchronously or synchronously across layers in a multiplex network. Updating asynchronously in the public goods game leads to higher frequencies of cooperation compared to synchronous updates. How large this effect is depends on the sensitivity of the game dynamics to changes in the number of cooperators surrounding a player, with the largest effect observed when players payoffs are small. The discovery of this effect enhances understanding of cooperation on multiplex networks, and demonstrates a new way to maintain cooperation in these systems.

Control System Upgrade for a Mass Property Measurement Facility

NASA Technical Reports Server (NTRS)

Chambers, William; Hinkle, R. Kenneth (Technical Monitor)

2002-01-01

The Mass Property Measurement Facility (MPMF) at the Goddard Space Flight Center has undergone modifications to ensure the safety of Flight Payloads and the measurement facility. The MPMF has been technically updated to improve reliability and increase the accuracy of the measurements. Modifications include the replacement of outdated electronics with a computer based software control system, the addition of a secondary gas supply in case of a catastrophic failure to the gas supply and a motor controlled emergency stopping feature instead of a hard stop.

The role of certification in the buyer/planner position: a case study at Harley-Davidson Motor Company.

PubMed

Orange, V J; Robinson, D E

1999-02-01

The use of buyer/planners may becoming more popular. If they are, the reason is probably that many companies are integrating materiel management skill sets as a way of increasing the effectiveness of their supply chains. Harley-Davidson recently created a supply management function composed of buyer/planners. This article describes the method it used to achieve the transition, the training plan it implemented to support the process, and the role management played in achieving success.

Asynchronous versus Synchronous Learning in Pharmacy Education

ERIC Educational Resources Information Center

Motycka, Carol A.; St. Onge, Erin L.; Williams, Jennifer

2013-01-01

Objective: To better understand the technology being used today in pharmacy education through a review of the current methodologies being employed at various institutions. Also, to discuss the benefits and difficulties of asynchronous and synchronous methodologies, which are being utilized at both traditional and distance education campuses.…

Knowledge Building in Asynchronous Discussion Groups: Going Beyond Quantitative Analysis

ERIC Educational Resources Information Center

Schrire, Sarah

2006-01-01

This contribution examines the methodological challenges involved in defining the collaborative knowledge-building processes occurring in asynchronous discussion and proposes an approach that could advance understanding of these processes. The written protocols that are available to the analyst provide an exact record of the instructional…

Creating and Nurturing Distributed Asynchronous Learning Environments.

ERIC Educational Resources Information Center

Kochtanek, Thomas R.; Hein, Karen K.

2000-01-01

Describes the evolution of a university course from a face-to-face experience to a Web-based asynchronous learning environment. Topics include cognition and learning; distance learning and distributed learning; student learning communities and the traditional classroom; the future as it relates to education and technology; collaborative student…

Learning about the Literacy Development of English Language Learners in Asynchronous Online Discussions

ERIC Educational Resources Information Center

De Oliveira, Luciana C.; Olesova, Larisa

2013-01-01

This study examined asynchronous online discussions in the online course "English Language Development" to identify themes related to participants' learning about the language and literacy development of English Language Learners when they facilitated online discussions to determine whether the participants developed sufficient…

Creating Asynchronous Online Learning Communities

ERIC Educational Resources Information Center

Kerr, Crystal

2009-01-01

This research project examined how to develop and sustain online, asynchronous learning communities in continuous intake, distance education environments for learners in grades 7 through 10. The study is an action research project that is based upon in-depth, qualitative data. Interviews were conducted with distance education teachers,…

48 CFR 8.1103 - Contract requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Contract requirements. 8.1103 Section 8.1103 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Leasing of Motor Vehicles 8.1103 Contract requirements...

Petroleum supply monthly, with data for September 1995

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1995-11-01

The Petroleum Supply Monthly (PSM) is one of a family of four publications produced by the Petroleum Supply Division within the Energy Information Administration (EIA) reflecting different levels of data timeliness and completeness. The other publications are the Weekly Petroleum Status Report (WPSR), the Winter Fuels Report, and the Petroleum Supply Annual (PSA). Data presented in the PSM describe the supply and disposition of petroleum products in the United States and major U.S. geographic regions. The data series describe production, imports and exports, inter-Petroleum Administration for Defense (PAD) District movements, and inventories by the primary suppliers of petroleum products inmore » the United States (50 States and the District of Columbia). The reporting universe includes those petroleum sectors in primary supply. Included are: petroleum refiners, motor gasoline blenders, operators of natural gas processing plants and fractionators, inter-PAD transporters, importers, and major inventory holders of petroleum products and crude oil. When aggregated, the data reported by these sectors approximately represent the consumption of petroleum products in the United States.« less

The Necessity of Real-Time: Fact and Fiction in Digital Reference Systems.

ERIC Educational Resources Information Center

Lankes, R. David; Shostack, Pauline

2002-01-01

Discussion of digital reference services and the use of real-time versus asynchronous services such as email focuses on data from the AskERIC digital reference service to demonstrate that asynchronous services are not only useful but may have greater utility than real-time systems. (Author/LRW)

Positioning (Mis)Aligned: The (Un)Making of Intercultural Asynchronous Computer-Mediated Communication

ERIC Educational Resources Information Center

Wu, Zhiwei

2018-01-01

Framed from positioning theory and dynamic systems theory, the paper reports on a naturalistic study involving four Chinese participants and their American peers in an intercultural asynchronous computer-mediated communication (ACMC) activity. Based on the moment-by-moment analysis and triangulation of forum posts, reflective essays, and…

Automated Feedback as a Convergence Tool

ERIC Educational Resources Information Center

Chenoweth, Tim; Corral, Karen; Scott, Kit

2016-01-01

This study evaluates two content delivery options for teaching a programming language to determine whether an asynchronous format can achieve the same learning efficacy as a traditional lecture (face-to-face) format. We use media synchronicity theory as a guide to choose media capabilities to incorporate into an asynchronous tutorial used…

Designing a Web-Based Asynchronous Innovation/Entrepreneurism Course

ERIC Educational Resources Information Center

Ghandforoush, Parviz

2017-01-01

Teaching an online fully asynchronous information technology course that requires students to ideate, build an e-commerce website, and develop an effective business plan involves a well-developed and highly engaging course design. This paper describes the design, development, and implementation of such a course and presents information on…

Asynchronous Assessment in a Large Lecture Marketing Course

ERIC Educational Resources Information Center

Downey, W. Scott; Schetzsle, Stacey

2012-01-01

Asynchronous assessment, which includes quizzes or exams online or outside class, offers marketing educators an opportunity to make more efficient use of class time and to enhance students' learning experiences by giving them more flexibility and choice in their assessment environment. In this paper, we examine the performance difference between…

Principles for Effective Asynchronous Online Instruction in Religious Studies

ERIC Educational Resources Information Center

McGuire, Beverley

2017-01-01

Asynchronous online instruction has become increasingly popular in the field of religious studies. However, despite voluminous research on online learning in general and numerous articles on online theological instruction, there has been little discussion of how to effectively design and deliver online undergraduate courses in religious studies.…

Investigating Asynchronous Online Communication: A Connected Stance Revealed

ERIC Educational Resources Information Center

Wegmann, Susan J.; McCauley, Joyce K.

2014-01-01

This research project explores the effects of altering the structure of discussion board formats to increase students' engagement and participation. This paper will present the findings of a two-university, two-class research project in which asynchronous discussion board entries were analyzed for substance. By using oral discourse analysis…

Theoretically Based Pedagogical Strategies Leading to Deep Learning in Asynchronous Online Gerontology Courses

ERIC Educational Resources Information Center

Majeski, Robin; Stover, Merrily

2007-01-01

Online learning has enjoyed increasing popularity in gerontology. This paper presents instructional strategies grounded in Fink's (2003) theory of significant learning designed for the completely asynchronous online gerontology classroom. It links these components with the development of mastery learning goals and provides specific guidelines for…

Developing a Successful Asynchronous Online Extension Program for Forest Landowners

ERIC Educational Resources Information Center

Zobrist, Kevin W.

2014-01-01

Asynchronous online Extension classes can reach a wide audience, is convenient for the learner, and minimizes ongoing demands on instructor time. However, producing such classes takes significant effort up front. Advance planning and good communication with contributors are essential to success. Considerations include delivery platforms, content…

Cultural Influences on Chinese Students' Asynchronous Online Learning in a Canadian University

ERIC Educational Resources Information Center

Zhao, Naxin; McDougall, Douglas

2008-01-01

This study explored six Chinese graduate students' asynchronous online learning in a large urban Canadian university. Individual interviews in Mandarin elicited their perceptions of online learning, their participation in it, and the cultural factors that influenced their experiences. In general, the participants had a positive attitude towards…

Language Use in Asynchronous Computer-Mediated Communication in Taiwan

ERIC Educational Resources Information Center

Huang, Daphne Li-jung

2009-01-01

This paper describes how Chinese-English bilinguals in Taiwan use their languages in asynchronous computer-mediated communication, specifically, via Bulletin Board System (BBS) and email. The main data includes two types: emails collected from a social network and postings collected from two BBS websites. By examining patterns of language choice…

Students' Use of Asynchronous Discussions for Academic Discourse Socialization

ERIC Educational Resources Information Center

Beckett, Gulbahar H.; Amaro-Jimenez, Carla; Beckett, Kelvin S.

2010-01-01

Our universities are becoming increasingly diverse at the same time as online asynchronous discussions (OADs) are emerging as the most important forum for computer mediated communication (CMC) in distance education. But there is shortage of studies that explore how graduate students from different ethnic, linguistic and cultural backgrounds use…

Effects of Belongingness and Synchronicity on Face-to-Face and Computer-Mediated Online Cooperative Pedagogy

ERIC Educational Resources Information Center

Saltarelli, Andrew John

2012-01-01

Previous research suggests asynchronous online computer-mediated communication (CMC) has deleterious effects on certain cooperative learning pedagogies (e.g., constructive controversy), but the processes underlying this effect and how it may be ameliorated remain unclear. This study tests whether asynchronous CMC thwarts belongingness needs…

Synchronous versus Asynchronous CMC and Transfer to Japanese Oral Performance

ERIC Educational Resources Information Center

Hirotani, Maki

2009-01-01

This study investigated the effects of synchronous and asynchronous CMC (computer-mediated communication)on the development of linguistic features of learners' speech in Japanese. Using learners from fourth-semester Japanese classes, the following research questions were examined: (a) Does CMC have positive effects on the development of oral…

A Group Intelligence-Based Asynchronous Argumentation Learning-Assistance Platform

ERIC Educational Resources Information Center

Huang, Chenn-Jung; Chang, Shun-Chih; Chen, Heng-Ming; Tseng, Jhe-Hao; Chien, Sheng-Yuan

2016-01-01

Structured argumentation support environments have been built and used in scientific discourse in the literature. However, to the best our knowledge, there is no research work in the literature examining whether student's knowledge has grown during learning activities with asynchronous argumentation. In this work, an intelligent computer-supported…

Participation, Interaction and Social Presence: An Exploratory Study of Collaboration in Online Peer Review Groups

ERIC Educational Resources Information Center

Zhao, Huahui; Sullivan, Kirk P. H.; Mellenius, Ingmarie

2014-01-01

A key reason for using asynchronous computer conferencing in instruction is its potential for supporting collaborative learning. However, few studies have examined collaboration in computer conferencing. This study examined collaboration in six peer review groups within an asynchronous computer conferencing. Eighteen tertiary students participated…

Asynchronous Group Review of EFL Writing: Interactions and Text Revisions

ERIC Educational Resources Information Center

Saeed, Murad Abdu; Ghazali, Kamila

2017-01-01

The current paper reports an empirical study of asynchronous online group review of argumentative essays among nine English as foreign language (EFL) Arab university learners joining English in their first, second, and third years at the institution. In investigating online interactions, commenting patterns, and how the students facilitate text…

The Role of Beliefs and Motivation in Asynchronous Online Learning in College-Level Classes

ERIC Educational Resources Information Center

Xie, Kui; Huang, Kun

2014-01-01

Epistemic and learning beliefs were found to affect college students' cognitive engagement and study strategies, as well as motivation in classroom settings. However, the relationships between epistemic and learning beliefs, motivation, learning perception, and students' actual learning participation in asynchronous online settings have been…

A Coding Scheme to Analyse the Online Asynchronous Discussion Forums of University Students

ERIC Educational Resources Information Center

Biasutti, Michele

2017-01-01

The current study describes the development of a content analysis coding scheme to examine transcripts of online asynchronous discussion groups in higher education. The theoretical framework comprises the theories regarding knowledge construction in computer-supported collaborative learning (CSCL) based on a sociocultural perspective. The coding…

Relationship of Metacognitive Monitoring with Interaction in an Asynchronous Online Discussion Forum

ERIC Educational Resources Information Center

Topcu, Abdullah

2010-01-01

Monitoring one's own performance accurately is essential for information-processing and self-regulation, which are indispensable in an online learning environment. In this article, the effect of metacognitive monitoring (MM) on interaction in an asynchronous online discussion forum was investigated. Transcripts of this forum, which was integrated…

Using Computer-Mediated Communication to Establish Social and Supportive Environments in Teacher Education

ERIC Educational Resources Information Center

Arnold, Nike; Ducate, Lara; Lomicka, Lara; Lord, Gillian

2005-01-01

This article examines social presence in virtual asynchronous learning communities among foreign language teachers. We present the findings of two studies investigating cross-institutional asynchronous forums created to engage participants in online dialogues regarding their foreign language teacher preparation experiences in and out of the…

The Effect of Synchronous and Asynchronous Participation on Students' Performance in Online Accounting Courses

ERIC Educational Resources Information Center

Duncan, Keith; Kenworthy, Amy; McNamara, Ray

2012-01-01

This article examines the relationship between MBA students' performance and participation in two online environments: a synchronous forum (chat room) and an asynchronous forum (discussion board) at an Australian university. The "quality" and "quantity" of students' participation is used to predict their final examination and…

Adding the Human Touch to Asynchronous Online Learning

ERIC Educational Resources Information Center

Glenn, Cynthia Wheatley

2018-01-01

For learners to actively accept responsibility in a virtual classroom platform, it is necessary to provide special motivation extending across the traditional classroom setting into asynchronous online learning. This article explores specific ways to do this that bridge the gap between ground and online students' learning experiences, and how…

Increasing Student Engagement Using Asynchronous Learning

ERIC Educational Resources Information Center

Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

2015-01-01

Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

A high-resolution time-to-digital converter using a three-level resolution

NASA Astrophysics Data System (ADS)

Dehghani, Asma; Saneei, Mohsen; Mahani, Ali

2016-08-01

In this article, a three-level resolution Vernier delay line time-to-digital converter (TDC) was proposed. The proposed TDC core was based on the pseudo-differential digital architecture that made it insensitive to nMOS and pMOS transistor mismatches. It also employed a Vernier delay line (VDL) in conjunction with an asynchronous read-out circuitry. The time interval resolution was equal to the difference of delay between buffers of upper and lower chains. Then, via the extra chain included in the lower delay line, resolution was controlled and power consumption was reduced. This method led to high resolution and low power consumption. The measurement results of TDC showed a resolution of 4.5 ps, 12-bit output dynamic range, and integral nonlinearity of 1.5 least significant bits. This TDC achieved the consumption of 68.43 µW from 1.1-V supply.

Semantic Maps Capturing Organization Knowledge in e-Learning

NASA Astrophysics Data System (ADS)

Mavridis, Androklis; Koumpis, Adamantios; Demetriadis, Stavros N.

e-learning, shows much promise in accessibility and opportunity to learn, due to its asynchronous nature and its ability to transmit knowledge fast and effectively. However without a universal standard for online learning and teaching, many systems are proclaimed as “e-learning-compliant”, offering nothing more than automated services for delivering courses online, providing no additional enhancement to reusability and learner personalization. Hence, the focus is not on providing reusable and learner-centered content, but on developing the technology aspects of e-learning. This current trend has made it crucial to find a more refined definition of what constitutes knowledge in the e-learning context. We propose an e-learning system architecture that makes use of a knowledge model to facilitate continuous dialogue and inquiry-based knowledge learning, by exploiting the full benefits of the semantic web as a medium capable for supplying the web with formalized knowledge.

Development of magneto-rheologial fluid (MRF) based clutch for output torque control of AC motors

NASA Astrophysics Data System (ADS)

Nguyen, Q. Hung; Do, H. M. Hieu; Nguyen, V. Quoc; Nguyen, N. Diep; Le, D. Thang

2018-03-01

In industry, the AC motor is widely used because of low price, power availability, low cost maintenance. The main disadvantages of AC motors compared to DC motors are difficulty in speed and torque control, requiring expensive controllers with complex control algorithms. This is the basic limitations in the widespread adoption of AC motor systems for industrial automation. One feasible solution for AC motor control is using MRF (magneto-rheological fluid) based clutches (shortly called MR clutches) Although there have been many studies on MR clutches, most of these clutches used traditional configuration with coils wound on the middle cylindrical part and a compotator is used to supply power to the coils. Therefore, this type of MR clutches possesses many disadvantages such as high friction and unstable applied current due to commutator, complex structure which causes difficulty in manufacture, assembly, and maintenance. In addition, the bottleneck problem of magnetic field is also a challenging issue. In this research, we will develop a new type of MR clutches that overcomes the abovementioned disadvantages of traditional MR clutches and more suitable for application in controlling of AC motor. Besides, in this study, speed and torque control system for AC motors using developed MR clutches is designed and experimental validated.

Architecture of Vagal Motor Units Controlling Striated Muscle of Esophagus: Peripheral Elements Patterning Peristalsis?

PubMed Central

Powley, Terry L.; Mittal, Ravinder K.; Baronowsky, Elizabeth A.; Hudson, Cherie N.; Martin, Felecia N.; McAdams, Jennifer L.; Mason, Jacqueline K.; Phillips, Robert J.

2013-01-01

Little is known about the architecture of the vagal motor units that control esophageal striated muscle, in spite of the fact that these units are necessary, and responsible, for peristalsis. The present experiment was designed to characterize the motor neuron projection fields and terminal arbors forming esophageal motor units. Nucleus ambiguus compact formation neurons of the rat were labeled by bilateral intracranial injections of the anterograde tracer dextran biotin. After tracer transport, thoracic and abdominal esophagi were removed and prepared as whole mounts of muscle wall without mucosa or submucosa. Labeled terminal arbors of individual vagal motor neurons (n = 78) in the esophageal wall were inventoried, digitized and analyzed morphometrically. The size of individual vagal motor units innervating striated muscle, throughout thoracic and abdominal esophagus, averaged 52 endplates per motor neuron, a value indicative of fine motor control. A majority (77%) of the motor terminal arbors also issued one or more collateral branches that contacted neurons, including nitric oxide synthase-positive neurons, of local myenteric ganglia. Individual motor neuron terminal arbors co-innervated, or supplied endplates in tandem to, both longitudinal and circular muscle fibers in roughly similar proportions (i.e., two endplates to longitudinal for every three endplates to circular fibers). Both the observation that vagal motor unit collaterals project to myenteric ganglia and the fact that individual motor units co-innervate longitudinal and circular muscle layers are consistent with the hypothesis that elements contributing to peristaltic programming inhere, or are “hardwired,” in the peripheral architecture of esophageal motor units. PMID:24044976

Architecture of vagal motor units controlling striated muscle of esophagus: peripheral elements patterning peristalsis?

PubMed

Powley, Terry L; Mittal, Ravinder K; Baronowsky, Elizabeth A; Hudson, Cherie N; Martin, Felecia N; McAdams, Jennifer L; Mason, Jacqueline K; Phillips, Robert J

2013-12-01

Little is known about the architecture of the vagal motor units that control esophageal striated muscle, in spite of the fact that these units are necessary, and responsible, for peristalsis. The present experiment was designed to characterize the motor neuron projection fields and terminal arbors forming esophageal motor units. Nucleus ambiguus compact formation neurons of the rat were labeled by bilateral intracranial injections of the anterograde tracer dextran biotin. After tracer transport, thoracic and abdominal esophagi were removed and prepared as whole mounts of muscle wall without mucosa or submucosa. Labeled terminal arbors of individual vagal motor neurons (n=78) in the esophageal wall were inventoried, digitized and analyzed morphometrically. The size of individual vagal motor units innervating striated muscle, throughout thoracic and abdominal esophagus, averaged 52 endplates per motor neuron, a value indicative of fine motor control. A majority (77%) of the motor terminal arbors also issued one or more collateral branches that contacted neurons, including nitric oxide synthase-positive neurons, of local myenteric ganglia. Individual motor neuron terminal arbors co-innervated, or supplied endplates in tandem to, both longitudinal and circular muscle fibers in roughly similar proportions (i.e., two endplates to longitudinal for every three endplates to circular fibers). Both the observation that vagal motor unit collaterals project to myenteric ganglia and the fact that individual motor units co-innervate longitudinal and circular muscle layers are consistent with the hypothesis that elements contributing to peristaltic programming inhere, or are "hardwired," in the peripheral architecture of esophageal motor units. © 2013.

The thalamus as a monitor of motor outputs.

PubMed Central

Guillery, R W; Sherman, S M

2002-01-01

Many of the ascending pathways to the thalamus have branches involved in movement control. In addition, the recently defined, rich innervation of 'higher' thalamic nuclei (such as the pulvinar) from pyramidal cells in layer five of the neocortex also comes from branches of long descending axons that supply motor structures. For many higher thalamic nuclei the clue to understanding the messages that are relayed to the cortex will depend on knowing the nature of these layer five motor outputs and on defining how messages from groups of functionally distinct output types are combined as inputs to higher cortical areas. Current evidence indicates that many and possibly all thalamic relays to the neocortex are about instructions that cortical and subcortical neurons are contributing to movement control. The perceptual functions of the cortex can thus be seen to represent abstractions from ongoing motor instructions. PMID:12626014

Simulation of motor unit recruitment and microvascular unit perfusion: spatial considerations.

PubMed

Fuglevand, A J; Segal, S S

1997-10-01

Muscle fiber activity is the principal stimulus for increasing capillary perfusion during exercise. The control elements of perfusion, i.e., microvascular units (MVUs), supply clusters of muscle fibers, whereas the control elements of contraction, i.e., motor units, are composed of fibers widely scattered throughout muscle. The purpose of this study was to examine how the discordant spatial domains of MVUs and motor units could influence the proportion of open capillaries (designated as perfusion) throughout a muscle cross section. A computer model simulated the locations of perfused MVUs in response to the activation of up to 100 motor units in a muscle with 40,000 fibers and a cross-sectional area of 100 mm2. The simulation increased contraction intensity by progressive recruitment of motor units. For each step of motor unit recruitment, the percentage of active fibers and the number of perfused MVUs were determined for several conditions: 1) motor unit fibers widely dispersed and motor unit territories randomly located (which approximates healthy human muscle), 2) regionalized motor unit territories, 3) reversed recruitment order of motor units, 4) densely clustered motor unit fibers, and 5) increased size but decreased number of motor units. The simulations indicated that the widespread dispersion of motor unit fibers facilitates complete capillary (MVU) perfusion of muscle at low levels of activity. The efficacy by which muscle fiber activity induced perfusion was reduced 7- to 14-fold under conditions that decreased the dispersion of active fibers, increased the size of motor units, or reversed the sequence of motor unit recruitment. Such conditions are similar to those that arise in neuromuscular disorders, with aging, or during electrical stimulation of muscle, respectively.

Linear magnetic motor/generator. [to generate electric energy using magnetic flux for spacecraft power supply

NASA Technical Reports Server (NTRS)

Studer, P. A. (Inventor)

1982-01-01

A linear magnetic motor/generator is disclosed which uses magnetic flux to provide mechanical motion or electrical energy. The linear magnetic motor/generator includes an axially movable actuator mechanism. A permament magnet mechanism defines a first magnetic flux path which passes through a first end portion of the actuator mechanism. Another permament magnet mechanism defines a second magnetic flux path which passes through a second end portion of the actuator mechanism. A drive coil defines a third magnetic flux path passing through a third central portion of the actuator mechanism. A drive coil selectively adds magnetic flux to and subtracts magnetic flux from magnetic flux flowing in the first and second magnetic flux path.

Comparison of 2- and 3-Phase Bearingless Slice Motor Concepts

NASA Astrophysics Data System (ADS)

Zürcher, Franz; Nussbaumer, Thomas; Gruber, Wolfgang; Kolar, Johann W.

Several processes in chemical, pharmaceutical, biotechnology and semiconductor industry require contactless levitation and rotation through a hermetically closed process chamber. A highly interesting topology for these applications is the “bearingless slice motor” concept, where already some research has been done in the past, especially focusing on topology and implementation issues. However, only little work has been done to evaluate the ideal number of motor phases. In this paper, a performance evaluation between 2-phase and 3-phase bearingless slice motor concepts is undertaken. It is shown, that 3-phase systems can supply almost the same power as state-of-the-art 2-phase systems and achieve nearly the same acceleration behavior, although they have significantly less power electronics effort.

Helmet weight simulator

NASA Technical Reports Server (NTRS)

Ashworth, B. R.; Hall, A. C.; Clark, C. E. (Inventor)

1981-01-01

A device for providing acceleration cues to the helmet of a simulator pilot is described. Pulleys are attached to both shoulders of the pilot. A cable is attached to both sides of the helmet and extends through the pulleys to a takeup reel that is controlled by a torque motor. Control signals are applied to a servo system including the torque motor, the takeup reel and a force transducer which supplies the feedback signal. In one embodiment of the invention the force transducer is in the cable and in another it is in the takeup reel.

High aspect ratio, remote controlled pumping assembly

DOEpatents

Brown, Steve B.; Milanovich, Fred P.

1995-01-01

A miniature dual syringe-type pump assembly which has a high aspect ratio and which is remotely controlled, for use such as in a small diameter penetrometer cone or well packer used in water contamination applications. The pump assembly may be used to supply and remove a reagent to a water contamination sensor, for example, and includes a motor, gearhead and motor encoder assembly for turning a drive screw for an actuator which provides pushing on one syringe and pulling on the other syringe for injecting new reagent and withdrawing used reagent from an associated sensor.

On Some Aspects of Energy Conservation in Industries

NASA Astrophysics Data System (ADS)

Rai, Keerti; Seksena, S. B. L.; Thakur, A. N.

2016-06-01

Energy demand has increased continuously due to advancement in technology and living standards of a large section of people resulting in a wide gap between supply and demand. One of the approaches to reduce this gap would be the adoption of measures of energy conservation in general and the efficient use of energy particularly in motor. This paper presents a review of the research activity in the field of efficiency optimization of three-phase induction motor drive. The approach is analyzed and the better option of energy conservation are identified.

Solar domestic hot water system installed at Texas City, Texas

NASA Technical Reports Server (NTRS)

1980-01-01

This is the final technical report of the solar energy system located at LaQuinta Motor Inn, Texas City, Texas. The system was designed to supply 63 percent of the total hot water load for a new 98 unit motor inn. The solar energy system consists of a 2100 square feet Raypack liquid flat plate collector subsystem and a 2500 gallon storage subsystem circulating hot water producing 3.67 x 10 to the 8th power Btu/year. Abstracts from the site files, specification references, drawings, installation, operation, and maintenance instructions are included.

A catalytic oligomeric motor that walks along a filament track

NASA Astrophysics Data System (ADS)

Huang, Mu-Jie; Kapral, Raymond

2015-06-01

Most biological motors in the cell execute chemically powered conformational changes as they walk on biopolymer filaments in order to carry out directed transport functions. Synthetic motors that operate in a similar manner are being studied since they have the potential to perform similar tasks in a variety of applications. In this paper, a synthetic nanomotor that moves along a filament track, without invoking motor conformational changes, is constructed and its properties are studied in detail. The motor is an oligomer comprising three linked beads with specific binding properties. The filament track is a stiff polymer chain, also described by a linear chain of linked coarse-grained molecular groups modeled as beads. Reactions on the filament that are catalyzed by a motor bead and use fuel in the environment, in conjunction within the binding affinities of the motor beads to the filament beads, lead to directed motion. The system operates out of equilibrium due to the state of the filament and supply of fuel. The motor, filament, and surrounding medium are all described at microscopic level that permits a full analysis of the motor motion. A stochastic model that captures the main trends seen in the simulations is also presented. The results of this study point to some of the key features that could be used to construct nanomotors that undergo biased walks powered by chemical reactions on filaments.

A catalytic oligomeric motor that walks along a filament track

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Mu-Jie, E-mail: mjhuang@chem.utoronto.ca; Kapral, Raymond, E-mail: rkapral@chem.utoronto.ca

Most biological motors in the cell execute chemically powered conformational changes as they walk on biopolymer filaments in order to carry out directed transport functions. Synthetic motors that operate in a similar manner are being studied since they have the potential to perform similar tasks in a variety of applications. In this paper, a synthetic nanomotor that moves along a filament track, without invoking motor conformational changes, is constructed and its properties are studied in detail. The motor is an oligomer comprising three linked beads with specific binding properties. The filament track is a stiff polymer chain, also described bymore » a linear chain of linked coarse-grained molecular groups modeled as beads. Reactions on the filament that are catalyzed by a motor bead and use fuel in the environment, in conjunction within the binding affinities of the motor beads to the filament beads, lead to directed motion. The system operates out of equilibrium due to the state of the filament and supply of fuel. The motor, filament, and surrounding medium are all described at microscopic level that permits a full analysis of the motor motion. A stochastic model that captures the main trends seen in the simulations is also presented. The results of this study point to some of the key features that could be used to construct nanomotors that undergo biased walks powered by chemical reactions on filaments.« less

High-speed asynchronous optical sampling for high-sensitivity detection of coherent phonons

NASA Astrophysics Data System (ADS)

Dekorsy, T.; Taubert, R.; Hudert, F.; Schrenk, G.; Bartels, A.; Cerna, R.; Kotaidis, V.; Plech, A.; Köhler, K.; Schmitz, J.; Wagner, J.

2007-12-01

A new optical pump-probe technique is implemented for the investigation of coherent acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with femtosecond resolution at scan rates of 10 kHz without any moving part in the set-up. Within 1 minute of data acquisition time signal-to-noise ratios better than 107 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles.

Dual stator winding variable speed asynchronous generator: optimal design and experiments

NASA Astrophysics Data System (ADS)

Tutelea, L. N.; Deaconu, S. I.; Popa, G. N.

2015-06-01

In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA].

Emotional first aid for a suicide crisis: comparison between Telephonic hotline and internet.

PubMed

Gilat, Itzhak; Shahar, Golan

2007-01-01

The telephone and the internet have become popular sources of psychological help in various types of distress, including a suicide crisis. To gain more insight into the unique features of these media, we compared characteristics of calls to three technologically mediated sources of help that are part of the volunteer-based Israeli Association for Emotional First Aid (ERAN): Telephonic hotline (n = 4426), personal chat (n = 373) and an asynchronous online support group (n = 954). Threats of suicide were much more frequent among participants in the asynchronous support group than the telephone and personal chat. These findings encourage further research into suicide-related interpersonal exchanges in asynchronous online support groups.

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings

NASA Astrophysics Data System (ADS)

Houghton, J. D. R.; Hays, G. C.

2001-03-01

For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures.

Asynchronous, macrotasked relaxation strategies for the solution of viscous, hypersonic flows

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.

1991-01-01

A point-implicit, asynchronous macrotasked relaxation of the steady, thin-layer, Navier-Stokes equations is presented. The method employs multidirectional, single-level storage Gauss-Seidel relaxation sweeps, which effectively communicate perturbations across the entire domain in 2n sweeps, where n is the dimension of the domain. In order to enhance convergence the application of relaxation factors to specific components of the Jacobian is examined using a stability analysis of the advection and diffusion equations. Attention is also given to the complications associated with asynchronous multitasking. Solutions are generated for hypersonic flows over blunt bodies in two and three dimensions with chemical reactions, utilizing single-tasked and multitasked relaxation strategies.

Electric vehicle (EV) storage supply chain risk and the energy market: A micro and macroeconomic risk management approach

NASA Astrophysics Data System (ADS)

Aguilar, Susanna D.

As a cost effective storage technology for renewable energy sources, Electric Vehicles can be integrated into energy grids. Integration must be optimized to ascertain that renewable energy is available through storage when demand exists so that cost of electricity is minimized. Optimization models can address economic risks associated with the EV supply chain- particularly the volatility in availability and cost of critical materials used in the manufacturing of EV motors and batteries. Supply chain risk can reflect itself in a shortage of storage, which can increase the price of electricity. We propose a micro-and macroeconomic framework for managing supply chain risk through utilization of a cost optimization model in combination with risk management strategies at the microeconomic and macroeconomic level. The study demonstrates how risk from the EVs vehicle critical material supply chain affects manufacturers, smart grid performance, and energy markets qualitatively and quantitatively. Our results illustrate how risk in the EV supply chain affects EV availability and the cost of ancillary services, and how EV critical material supply chain risk can be mitigated through managerial strategies and policy.

48 CFR 408.1103 - Contract requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Contract requirements. 408.1103 Section 408.1103 Federal Acquisition Regulations System DEPARTMENT OF AGRICULTURE COMPETITION AND ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Leasing of Motor Vehicles 408.1103 Contract...

48 CFR 908.1104 - Contract clauses.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Contract clauses. 908.1104 Section 908.1104 Federal Acquisition Regulations System DEPARTMENT OF ENERGY COMPETITION ACQUISITION PLANNING REQUIRED SOURCES OF SUPPLIES AND SERVICES Leasing of Motor Vehicles 908.1104 Contract clauses. (f...

Respiratory transfer value has fail-safe feature

NASA Technical Reports Server (NTRS)

Puccinelli, A. A.; Smith, J. R., Jr.

1965-01-01

Quick-acting, remote controlled valve connects either one of two oxygen or air supplies to a breathing tube. The valve, which is fall-safe, incorporates a cammed piston arrangement that is driven by a remote controlled reversible rotary solenoid or reversible electric motor.

Sequential Polarity-Reversing Circuit

NASA Technical Reports Server (NTRS)

Labaw, Clayton C.

1994-01-01

Proposed circuit reverses polarity of electric power supplied to bidirectional dc motor, reversible electro-mechanical actuator, or other device operating in direction depending on polarity. Circuit reverses polarity each time power turned on, without need for additional polarity-reversing or direction signals and circuitry to process them.

Federal Legislation Affecting Motor Vehicle Design

DOT National Transportation Integrated Search

1975-03-01

The regulations included in the report are those in effect as of April 1, 1974. The report does not reflect changes in automobile emission standards under the Clean Air Act, which would result from enactment of H.R. 14368, the 'Energy Supply and Envi...

Revised Vehicle Miles of Travel for Passenger Cars and Light Trucks, 1975 to 1993

DOT National Transportation Integrated Search

1995-09-21

The Federal Highway Administration (FHWA) historically has supplied registered : vehicle and vehicle miles of travel (VMT) data for use with the National Center : for Statistics and Analysis (NCSA) motor vehicle injury and fatality data. : However, t...

Different visuomotor processes maturation rates in children support dual visuomotor learning systems.

PubMed

Gómez-Moya, Rosinna; Díaz, Rosalinda; Fernandez-Ruiz, Juan

2016-04-01

Different processes are involved during visuomotor learning, including an error-based procedural and a strategy based cognitive mechanism. Our objective was to analyze if the changes in the adaptation or the aftereffect components of visuomotor learning measured across development, reflected different maturation rates of the aforementioned mechanisms. Ninety-five healthy children aged 4-12years and a group of young adults participated in a wedge prism and a dove prism throwing task, which laterally displace or horizontally reverse the visual field respectively. The results show that despite the age-related differences in motor control, all children groups adapted in the error-based wedge prisms condition. However, when removing the prism, small children showed a slower aftereffects extinction rate. On the strategy-based visual reversing task only the older children group reached adult-like levels. These results are consistent with the idea of different mechanisms with asynchronous maturation rates participating during visuomotor learning. Copyright © 2016 Elsevier B.V. All rights reserved.

Single-cell topological RNA-Seq analysis reveals insights into cellular differentiation and development

PubMed Central

Rizvi, Abbas H.; Camara, Pablo G.; Kandror, Elena K.; Roberts, Thomas J.; Schieren, Ira; Maniatis, Tom; Rabadan, Raul

2017-01-01

Transcriptional programs control cellular lineage commitment and differentiation during development. Understanding cell fate has been advanced by studying single-cell RNA-seq, but is limited by the assumptions of current analytic methods regarding the structure of data. We present single-cell topological data analysis (scTDA), an algorithm for topology-based computational analyses to study temporal, unbiased transcriptional regulation. Compared to other methods, scTDA is a non-linear, model-independent, unsupervised statistical framework that can characterize transient cellular states. We applied scTDA to the analysis of murine embryonic stem cell (mESC) differentiation in vitro in response to inducers of motor neuron differentiation. scTDA resolved asynchrony and continuity in cellular identity over time, and identified four transient states (pluripotent, precursor, progenitor, and fully differentiated cells) based on changes in stage-dependent combinations of transcription factors, RNA-binding proteins and long non-coding RNAs. scTDA can be applied to study asynchronous cellular responses to either developmental cues or environmental perturbations. PMID:28459448

Student Outcomes Associated with Use of Asynchronous Online Discussion Forums in Gross Anatomy Teaching

ERIC Educational Resources Information Center

Green, Rodney A.; Hughes, Diane L.

2013-01-01

Asynchronous online discussion forums are increasingly common in blended learning environments but the relationship to student learning outcomes has not been reported for anatomy teaching. Forums were monitored in two multicampus anatomy courses; an introductory first year course and a second year physiotherapy-specific course. The forums are…

At a Distance: A Comparative Study of Distance Delivery Modalities for PhD Nursing Students

ERIC Educational Resources Information Center

Black, Andrew G.

2010-01-01

This study sought to ascertain and compare the attitudes and perceptions of PhD nursing students attending their coursework through synchronous and asynchronous means at two different universities. Many studies have been performed comparing both synchronous videoconferencing and asynchronous online education with the traditional classroom, but no…

Students' Desired and Experienced Levels of Connectivity to an Asynchronous, Online, Distance Degree Program

ERIC Educational Resources Information Center

Schroeder, Shawnda; Baker, Mary; Terras, Katherine; Mahar, Patti; Chiasson, Kari

2016-01-01

This study examined graduate students' desired and experienced levels of connectivity in an online, asynchronous distance degree program. Connectivity was conceptualized as the students' feelings of community and involvement, not their level of access to the Internet. Graduate students enrolled in a distance degree program were surveyed on both…

Three Interaction Patterns on Asynchronous Online Discussion Behaviours: A Methodological Comparison

ERIC Educational Resources Information Center

Jo, I.; Park, Y.; Lee, H.

2017-01-01

An asynchronous online discussion (AOD) is one format of instructional methods that facilitate student-centered learning. In the wealth of AOD research, this study evaluated how students' behavior on AOD influences their academic outcomes. This case study compared the differential analytic methods including web log mining, social network analysis…

Microbial infection affects egg viability and incubation behavior in a tropical passerine.

Treesearch

Mark I. Cook; Steven R. Beissinger; Gary A. Toranzos; Roberto A. Arendt Rodriguez

2004-01-01

Many avian species initiate incubation before clutch completion, which causes eggs to hatch asynchronously. This influences brood competitive dynamics and often results in nestling mortality. The prevailing hypotheses contend that parents incubate early because asynchronous hatching provides fitness benefits to parents or surviving offspring. An alternative idea is...

FIFO Buffer for Asynchronous Data Streams

NASA Technical Reports Server (NTRS)

Bascle, K. P.

1985-01-01

Variable-rate, asynchronous data signals from up to four measuring instruments or other sources combined in first-in/first-out (FIFO) buffer for transmission on single channel. Constructed in complementary metal-oxide-semiconductor (CMOS) logic, buffer consumes low power (only 125 mW at 5V) and conforms to aerospace standards of reliability and maintainability.

Critical Thinking in Asynchronous Online Discussion: An Investigation of Student Facilitation Techniques

ERIC Educational Resources Information Center

Lim, Sze Chung Raymond; Cheung, Wing Sum; Hew, Khe Foon

2011-01-01

Background: In the last decade, asynchronous online discussion forums have become a primary focus of many educational researchers. Some advocates believed that the process of typing out messages in itself can promote in-depth critical thinking skills. Nevertheless, empirical research has not provided much support for this claim in natural…

Interaction and Cognition in Asynchronous Computer Conferencing

ERIC Educational Resources Information Center

Schrire, Sarah

2004-01-01

This paper is based on a multiple-case study of the learning process in three asynchronous computer conferences. The conferences were part of the distance learning component in doctoral degree courses in computing technology in education offered at an American university. The conferences were analyzed from a number of perspectives, the emphasis in…

Socially Shared Metacognitive Regulation in Asynchronous CSCL in Science: Functions, Evolution and Participation

ERIC Educational Resources Information Center

Iiskala, Tuike; Volet, Simone; Lehtinen, Erno; Vauras, Marja

2015-01-01

The significance of socially shared metacognitive regulation (SSMR) in collaborative learning is gaining momentum. To date, however, there is still a paucity of research of how SSMR is manifested in asynchronous computer-supported collaborative learning (CSCL), and hardly any systematic investigation of SSMR's functions and evolution across…

The Effects of Self-Generated Synchronous and Asynchronous Visual Speech Feedback on Overt Stuttering Frequency

ERIC Educational Resources Information Center

Snyder, Gregory J.; Hough, Monica Strauss; Blanchet, Paul; Ivy, Lennette J.; Waddell, Dwight

2009-01-01

Purpose: Relatively recent research documents that visual choral speech, which represents an externally generated form of synchronous visual speech feedback, significantly enhanced fluency in those who stutter. As a consequence, it was hypothesized that self-generated synchronous and asynchronous visual speech feedback would likewise enhance…

Cooperative Learning in Graduate Student Projects: Comparing Synchronous versus Asynchronous Collaboration

ERIC Educational Resources Information Center

Strang, Kenneth

2013-01-01

Cooperative learning was applied in a graduate project management course to compare the effectiveness of asynchronous versus synchronous online team meetings. An experiment was constructed to allocate students to project teams while ensuring there was a balance of requisite skills, namely systems analysis and design along with HTML/Javascript…

Asynchronous Education: A Blueprint for the Future of Adult Learning.

ERIC Educational Resources Information Center

Krueger, Lyle L.; Porter, Cyndi Wilson; Burke, Daniel

While the distance learning curriculum at Lakeland College (Wisconsin) began 20 years ago, the idea for Lakeland Online was conceived about two and one-half years ago. A variety of delivery modes were considered before discovering Convene software. Since the communication process enabled by the Convene software is asynchronous and requires only a…

Synchronous and Asynchronous Communication in Distance Learning: A Review of the Literature

ERIC Educational Resources Information Center

Watts, Lynette

2016-01-01

Distance learning is commonplace in higher education, with increasing numbers of students enjoying the flexibility e-learning provides. Keeping students connected with peers and instructors has been a challenge with e-learning, but as technology has advanced, the methods by which educators keep students engaged, synchronously and asynchronously,…

Evaluating the Quality of Interaction in Asynchronous Discussion Forums in Fully Online Courses

ERIC Educational Resources Information Center

Nandi, Dip; Hamilton, Margaret; Harland, James

2012-01-01

Fully online courses are becoming progressively more popular because of their "anytime anywhere" learning flexibility. One of the ways students interact with each other and with the instructors within fully online learning environments is via asynchronous discussion forums. However, student engagement in online discussion forums does not…

Real-Time Implementation of an Asynchronous Vision-Based Target Tracking System for an Unmanned Aerial Vehicle

DTIC Science & Technology

2007-06-01

Chin Khoon Quek. “Vision Based Control and Target Range Estimation for Small Unmanned Aerial Vehicle.” Master’s Thesis, Naval Postgraduate School...December 2005. [6] Kwee Chye Yap. “Incorporating Target Mensuration System for Target Motion Estimation Along a Road Using Asynchronous Filter

Reflections of Students in Their Use of Asynchronous Online Seminars

ERIC Educational Resources Information Center

Groves, Mark; O'Donoghue, John

2009-01-01

This paper reports on research that has been carried out into the use, process, and effectiveness of an asynchronous online seminar within an undergraduate sports studies degree programme. Contemporary sources are used to justify the use of technology supported learning (TSL) in higher education and to inform a reflective and critical account of…

Using Asynchronous Electronic Surveys to Help In-Class Revision: A Case Study

ERIC Educational Resources Information Center

Tong, Vincent C. H.

2012-01-01

Synchronous e-voting systems (commonly known as "clickers") have become increasingly popular as they can be used to enhance interactivity in lectures. Asynchronous electronic surveys (AESs), unlike these voting system, usually serve as a method of gathering feedback before or after teaching sessions. This paper describes and evaluates a project…

Argumentation in a Multi Party Asynchronous Computer Mediated Conference: A Generic Analysis

ERIC Educational Resources Information Center

Coffin, Caroline; Painter, Clare; Hewings, Ann

2005-01-01

This paper draws on systemic functional linguistic genre analysis to illuminate the way in which post graduate applied linguistics students structure their argumentation within a multi party asynchronous computer mediated conference. Two conference discussions within the same postgraduate course are compared in order to reveal the way in which…

The Socratic Dialogue in Asynchronous Online Discussions: Is Constructivism Redundant?

ERIC Educational Resources Information Center

Kingsley, Paul

2011-01-01

Purpose: This paper aims to examine Socratic dialogue in asynchronous online discussions in relation to constructivism. The links between theory and practice in teaching are to be discussed whilst tracing the origins of Socratic dialogue and recent trends and use of seminar in research based institutions. Design/methodology/approach: Many online…

Asynchronous Online Peer Assistance: Telephone Messages of Encouragement in Post Licensure Nursing Programs

ERIC Educational Resources Information Center

Melrose, Sherri; Swettenham, Steve

2012-01-01

Peer assistance activities can strengthen online learning environments. And yet, like other professional adult learners, working post licensure nurses attending university part time to upgrade their credentials may have limited interest in student-to-student interaction. Some intentionally choose asynchronous self-paced courses so they can work on…

Thematic Analysis of the "Games" Students Play in Asynchronous Learning Environments

ERIC Educational Resources Information Center

MacMillan, Thalia; Forte, Michele; Grant, Cynthia

2014-01-01

The dynamics of the student-student relationship within the asynchronous online classroom, as evidenced by conversations in an online discussion board, is a balancing act potentially more complex than those occurring in real-time. In order for learning to truly be considered effective, a collaborative, safe environment needs to exist among…

Scaffolding Collaborative Argumentation in Asynchronous Discussions with Message Constraints and Message Labels

ERIC Educational Resources Information Center

Jeong, Allan; Joung, Sunyoung

2007-01-01

This study examined the effects of message constraints and labels on collaborative argumentation in asynchronous online discussions. Thirty-eight undergraduate students in an introductory educational technology course were assigned to one of three groups. In one group, students posted specific types of messages using a prescribed set of message…

Flipping the Online Classroom with Web 2.0: The Asynchronous Workshop

ERIC Educational Resources Information Center

Cummings, Lance

2016-01-01

This article examines how Web 2.0 technologies can be used to "flip" the online classroom by creating asynchronous workshops in social environments where immediacy and social presence can be maximized. Using experience teaching several communication and writing classes in Google Apps (Google+, Google Hangouts, Google Drive, etc.), I…

Peer Moderation of Asynchronous Online Discussions: An Exploratory Study of Peer E-Moderating Behaviour

ERIC Educational Resources Information Center

Ghadirian, Hajar; Ayub, Ahmad Fauzi Mohd

2017-01-01

This study explored patterns of e-moderating behaviour students performed when they were assigned as peer moderators of asynchronous online discussions in a reciprocal manner. Eighty-four students from an undergraduate blended course were observed during a 7-week-long online discussions. Using quantitative content analysis peer moderators'…

Asynchronous CMC, Collaboration and the Development of Critical Thinking in a Graduate Seminar in Applied Linguistics

ERIC Educational Resources Information Center

Abrams, Zsuzsanna I.

2005-01-01

A primary objective of graduate education, and often promoted by peer collaboration tasks, is the development of critical thinking skills. The present study compares how graduate students enrolled in a qualitative research design course in applied linguistics utilized asynchronous computer-mediated communication (ACMC) and face-to-face…

Asynchronous Computer-Mediated Corrective Feedback and the Correct Use of Prepositions: Is It Really Effective?

ERIC Educational Resources Information Center

Hosseini, Seyyed Behrooz

2012-01-01

An area that has recently attracted increasing attention is providing feedback on learners' writing accuracy through the Internet. However, research in this area has largely focused on synchronous communication, i.e., chatting, with fewer studies assessing asynchronous technologies, i.e., e-mailing. Therefore, this study investigates the…

The Role of Technology-Based Scaffolding in Problem-Based Online Asynchronous Discussion

ERIC Educational Resources Information Center

Ak, Serife

2016-01-01

This study examined the effects of technology-based scaffolds that were composed through the use of the seven-stage, problem-based learning strategy on knowledge construction in a problem-based online asynchronous discussion. In a quasi-experimental setting, 60 students in an undergraduate Instructional Technology and Material Design course were…

Superconducting magnetic energy storage for asynchronous electrical systems

DOEpatents

Boenig, H.J.

1984-05-16

It is an object of the present invention to provide superconducting magnetic energy storage for a plurality of asynchronous electrical systems. It is a further object of the present invention to provide load leveling and stability improvement in a plurality of independent ac systems using a single superconducting magnetic energy storage coil.

Factors Affecting Pre-Service Teachers' Participation in Asynchronous Discussion: The Case of Iran

ERIC Educational Resources Information Center

Ebrahimi, Alice; Faghih, Esmail; Marandi, Seyyedeh Susan

2016-01-01

This study reports on a qualitative small-scale exploratory study which examined the factors influencing 32 Iranian pre-service language teachers' participation in online asynchronous text-based discussion forums. By adopting a multiple case study design and analysing data gathered through semi-structured interviews and participants' online…

A Dynamic Analysis of the Interplay between Asynchronous and Synchronous Communication in Online Learning: The Impact of Motivation

ERIC Educational Resources Information Center

Giesbers, B.; Rienties, B.; Tempelaar, D.; Gijselaers, W.

2014-01-01

With the increased affordances of synchronous communication tools, more opportunities for online learning to resemble face-to-face settings have recently become available. However, synchronous communication does not afford as much time for reflection as asynchronous communication. Therefore, a combination of synchronous and asynchronous…

An Investigation of Assessment and Feedback Practices in Fully Asynchronous Online Undergraduate Mathematics Courses

ERIC Educational Resources Information Center

Trenholm, Sven; Alcock, Lara; Robinson, Carol

2015-01-01

Research suggests it is difficult to learn mathematics in the fully asynchronous online (FAO) instructional modality, yet little is known about associated teaching and assessment practices. In this study, we investigate FAO mathematics assessment and feedback practices in particular consideration of both claims and findings that these practices…

An Integrated Approach to Preempt Cheating on Asynchronous, Objective, Online Assessments in Graduate Business Classes

ERIC Educational Resources Information Center

Sullivan, Daniel P.

2016-01-01

Cheating, left untended, erodes the validity of evaluation and, ultimately, corrupts the legitimacy of a course. We profile an approach to manage, with an eye toward preempting, cheating on asynchronous, objective, online quizzes. This approach taps various technological and social solutions to academic dishonesty, integrating them into a…

An Examination of Computer Engineering Students' Perceptions about Asynchronous Discussion Forums

ERIC Educational Resources Information Center

Ozyurt, Ozcan; Ozyurt, Hacer

2013-01-01

This study was conducted in order to reveal the usage profiles and perceptions of Asynchronous Discussion Forums (ADFs) of 126 computer engineering students from the Computer Engineering Department in a university in Turkey. By using a mixed methods research design both quantitative and qualitative data were collected and analyzed. Research…

Students' Learning in Asynchronous Discussion Forums: A Meta-Analysis

ERIC Educational Resources Information Center

Martono, Fkipuntan; Salam, Urai

2017-01-01

Asynchronous discussion forums are among the most preferred tools chosen to foster learning opportunities and knowledge construction. To reveal the cognitive engagement evidenced in the transcripts of the discussion forums, this study presents 51 papers. 17 papers reported research on students' attitude toward the use of ICT for learning, 16…

Student Moderators in Asynchronous Online Discussion: A Question of Questions

ERIC Educational Resources Information Center

Zingaro, Daniel

2012-01-01

Much current research exalts the benefits of having students facilitate weekly discussions in asynchronous online courses. This study seeks to add to what is known about student moderation through an analysis of the types of questions students use to spur each discussion. Prior experimental work has demonstrated that the types of questions posed…

Content Analysis Coding Schemes for Online Asynchronous Discussion

ERIC Educational Resources Information Center

Weltzer-Ward, Lisa

2011-01-01

Purpose: Researchers commonly utilize coding-based analysis of classroom asynchronous discussion contributions as part of studies of online learning and instruction. However, this analysis is inconsistent from study to study with over 50 coding schemes and procedures applied in the last eight years. The aim of this article is to provide a basis…

Does the Medium Dictate the Message? Cultivating E-Communication in an Asynchronous Environment.

ERIC Educational Resources Information Center

Kiernan, Mary; Thomas, Pete; Woodroffe, Mark

Virtual learning environments (VLEs) are often perceived by education establishments as an opportunity to widen access without traditional overheads. An integral part of most VLEs is asynchronous computer conferencing and on-line moderators must help students migrate quickly to the new virtual environment to minimize learning disruption. This…

An Investigation of Student Practices in Asynchronous Computer Conferencing Courses

ERIC Educational Resources Information Center

Peters, Vanessa L.; Hewitt, Jim

2010-01-01

This study investigated the online practices of students enrolled in graduate-level distance education courses. Using interviews and a questionnaire as data sources, the study sought to: (a) identify common practices that students adopt in asynchronous discussions, and (b) gain an understanding of why students adopt them. An analysis of the data…

Asynchronous Replication and Autosome-Pair Non-Equivalence in Human Embryonic Stem Cells

PubMed Central

Dutta, Devkanya; Ensminger, Alexander W.; Zucker, Jacob P.; Chess, Andrew

2009-01-01

A number of mammalian genes exhibit the unusual properties of random monoallelic expression and random asynchronous replication. Such exceptional genes include genes subject to X inactivation and autosomal genes including odorant receptors, immunoglobulins, interleukins, pheromone receptors, and p120 catenin. In differentiated cells, random asynchronous replication of interspersed autosomal genes is coordinated at the whole chromosome level, indicative of chromosome-pair non-equivalence. Here we have investigated the replication pattern of the random asynchronously replicating genes in undifferentiated human embryonic stem cells, using fluorescence in situ hybridization based assay. We show that allele-specific replication of X-linked genes and random monoallelic autosomal genes occur in human embryonic stem cells. The direction of replication is coordinated at the whole chromosome level and can cross the centromere, indicating the existence of autosome-pair non-equivalence in human embryonic stem cells. These results suggest that epigenetic mechanism(s) that randomly distinguish between two parental alleles are emerging in the cells of the inner cell mass, the source of human embryonic stem cells. PMID:19325893

Air Temperature Distribution Measurement Using Asynchronous-Type Sound Probe

NASA Astrophysics Data System (ADS)

Katano, Yosuke; Wakatsuki, Naoto; Mizutani, Koichi

2009-07-01

In conventional temperature measurement using a sound probe, the operation beginnings of two acoustic sensors must be completely synchronized to measure time of flight (TOF), tf, because the precision of synchronization determines TOF measurement accuracy. A wireless local area network (LAN) is convenient for constructing a sensing grid; however, it causes a fluctuation in the delay of millisecond order. Therefore, it cannot provide sufficient precision for synchronizing acoustic sensors. In previous studies, synchronization was achieved by a trigger line using a coaxial cable; however, the cable reduces the flexibility of a wireless sensing grid especially in larger-scale measurement. In this study, an asynchronous-type sound probe is devised to compensate for the effect of the delay of millisecond order caused by the network. The validity of the probe was examined, and the air temperature distribution was measured using this means. A matrix method is employed to obtain the distribution. Similar results were observed using both asynchronous-type sound probes and thermocouples. This shows the validity of the use of a sensing grid with an asynchronous-type sound probe for temperature distribution measurement even if the trigger line is omitted.

Research on navigation of satellite constellation based on an asynchronous observation model using X-ray pulsar

NASA Astrophysics Data System (ADS)

Guo, Pengbin; Sun, Jian; Hu, Shuling; Xue, Ju

2018-02-01

Pulsar navigation is a promising navigation method for high-altitude orbit space tasks or deep space exploration. At present, an important reason for restricting the development of pulsar navigation is that navigation accuracy is not high due to the slow update of the measurements. In order to improve the accuracy of pulsar navigation, an asynchronous observation model which can improve the update rate of the measurements is proposed on the basis of satellite constellation which has a broad space for development because of its visibility and reliability. The simulation results show that the asynchronous observation model improves the positioning accuracy by 31.48% and velocity accuracy by 24.75% than that of the synchronous observation model. With the new Doppler effects compensation method in the asynchronous observation model proposed in this paper, the positioning accuracy is improved by 32.27%, and the velocity accuracy is improved by 34.07% than that of the traditional method. The simulation results show that without considering the clock error will result in a filtering divergence.

Asynchronous hatching and food limitation: A test of Lack's hypothesis

USGS Publications Warehouse

Skagen, Susan Knight

1988-01-01

Lack's (1954, 1968) hypothesis that asynchronous hatching of altricial birds is an adaptive response to unpredictable food shortages during the breeding season was examined in the highly granivorous Zebra Finch (Poephila guttata). I compared growth and survival of nestlings in asynchronous and artificially created synchronous broods reared under food-limited and food-abundant conditions in an aviary. I also examined the role of parental experience on survival and growth of nestlings.There was no differential mortality of Zebra Finch nestlings due to either asynchrony or food abundance. Young in abundant food treatments grew more rapidly, however, than those in food-restricted treatments. Heaviest Zebra Finch nestlings in a brood grew more quickly than their lightest siblings when food was limited, supporting Lack's hypothesis. Further, differential survival of light and heavy siblings occurred when food was abundant, suggesting that asynchronous hatching can be maladaptive under some ecological conditions. Nestlings reared by inexperienced parents suffered greater mortality and slower growth when food was abundant than nestlings raised by experienced parents. Prefledging mass was correlated with size at adulthood

Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

NASA Astrophysics Data System (ADS)

Wang, Jin; Peng, Wei; Liu, Song

2017-10-01

Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

A formal model of asynchronous communication and its use in mechanically verifying a biphase mark protocol

NASA Technical Reports Server (NTRS)

Moore, J. Strother

1992-01-01

In this paper we present a formal model of asynchronous communication as a function in the Boyer-Moore logic. The function transforms the signal stream generated by one processor into the signal stream consumed by an independently clocked processor. This transformation 'blurs' edges and 'dilates' time due to differences in the phases and rates of the two clocks and the communications delay. The model can be used quantitatively to derive concrete performance bounds on asynchronous communications at ISO protocol level 1 (physical level). We develop part of the reusable formal theory that permits the convenient application of the model. We use the theory to show that a biphase mark protocol can be used to send messages of arbitrary length between two asynchronous processors. We study two versions of the protocol, a conventional one which uses cells of size 32 cycles and an unconventional one which uses cells of size 18. We conjecture that the protocol can be proved to work under our model for smaller cell sizes and more divergent clock rates but the proofs would be harder.

Quasi-perfect FIFO: Synchronous or asynchronous with application in controller design for the UNICON laser memory. [digital memory and buffer storage

NASA Technical Reports Server (NTRS)

Lim, R. S.

1974-01-01

The first-in-first-out memory buffer (FIFO), is an elastic digital memory whose main application is in data buffering between devices operating at different rates. Data written into the top is moved autonomously down toward the bottom of the FIFO to the lowest unoccupied location, and data read from the bottom of the FIFO will cause data from the top to move autonomously down toward the bottom. The FIFO is available in MOS LSI asynchronous form with data rate in the 1 MHz region. The FIFO described yields a simple high-speed iterative implementation, either synchronous of asynchronous. Because of this simple iterative structure, the FIFO is expandable in both number of words and bits per word, and it is attractive from the viewpoint of integrated-circuit production. For the synchronous FIFO, a model was built and successfully used in the controller for the UNICON laser memory. For the asynchronous FIFO, a model was built and also successfully used in a high-performance magnetic tape controller.

Exploring Online Asynchronous Counseling With Tobacco Treatment Specialists in the QUIT-PRIMO and National Dental PBRN HI-QUIT Studies: Who Uses It and What Do They Say?

PubMed

Williams, Jessica H; DeLaughter, Kathryn; Volkman, Julie E; Sadasivam, Rajani S; Ray, Midge N; Gilbert, Gregg H; Houston, Thomas K

2018-06-01

To describe the content of messages sent by smokers through asynchronous counseling within a Web-based smoking cessation intervention. Qualitative. National community-based setting of patients who had been engaged by the medical or dental practices at which they attended or via Google advertisements. Adults older than 19 years who were current smokers and interested in quitting. Participants throughout the United States referred to a Web-based cessation intervention by their medical or dental provider or by clicking on a Google advertisement. We conducted a qualitative review of 742 asynchronous counseling messages sent by 270 Web site users. Messages were reviewed, analyzed, and organized into qualitative themes by the investigative team. The asynchronous counseling feature of the intervention was used most frequently by smokers who were white (87%), female (67%), aged 45 to 54 (32%), and who had at least some college-level education (70%). Qualitative analysis yielded 7 basic themes-Talk about the Process of Quitting, Barriers to Quitting, Reasons to Quit, Quit History, Support and Strategies for Quitting, Quitting with Medication, and Quit Progress. The most common theme was Support and Strategies for Quitting with 255 references among all messages. We found rich communication across the spectrum of the quit process, from persons preparing to quit to those who had successfully quit. Asynchronous smoking cessation counseling provides a promising means of social support for smokers during the quit process.

Hatching behavior of eastern long-necked turtles (Chelodina longicollis): The influence of asynchronous environments on embryonic heart rate and phenotype.

PubMed

McGlashan, Jessica K; Loudon, Fiona K; Thompson, Michael B; Spencer, Ricky-John

2015-10-01

Variable temperatures within a nest cause asynchronous development within clutches of freshwater turtle embryos, yet synchronous hatching occurs and is thought to be an important survival strategy for hatchlings. Metabolic compensation and circadian rhythms in heart rates of embryonic turtles indicate the potential of communication between embryos in a nest. Heart rates were used to identify metabolic circadian rhythms in clutches of an Australian freshwater turtle (Chelodina longicollis) and determine whether embryos metabolically compensate and hatch synchronously when incubated in asynchronous environments. The effects of a group environment during incubation on egg development and incubation period were also investigated during the final 3 weeks of development. Chelodina longicollis hatch synchronously and metabolically compensate so that less advanced embryos catch up to more advanced clutch-mates. Heart rates of embryos remained stable from week 4-7 in asynchronous (M=89 bpm) and synchronous (M=92 bpm) groups and declined in the final 2 weeks of incubation (M=72 and 77 bpm). Circadian rhythms were present throughout development and diel heart rates of embryos in asynchronous groups showed less deviation from the mean (M=-0.5 bpm) than synchronous groups (M=-4 bpm). Eggs incubated in groups had a significantly shorter incubation period than eggs incubated individually. Phenotypic traits including size, performance, and growth of all hatchlings were not affected. Egg position within a turtle nest is important for coordinating development throughout incubation and facilitating synchronous hatching. Copyright © 2015 Elsevier Inc. All rights reserved.

Telemedicine for children with developmental disabilities: a more effective clinical process than office-based care.

PubMed

Langkamp, Diane L; McManus, Mark D; Blakemore, Susan D

2015-02-01

The literature on the use of telemedicine for children with developmental disabilities (DD) is limited and mostly describes telemedicine being used to link patients with distant subspecialty multidisciplinary care. Parents generally have reported satisfaction with such care and have perceived it to be equally effective as in-person care. Here we report on the use of school-based asynchronous telemedicine to connect children with DD with primary care providers. We developed Tele-Health-Kids, a school-based program using asynchronous telemedicine to connect children with DD with their primary care physician for the care of minor illnesses. We surveyed parents at enrollment and after the child's first telemedicine visit to assess satisfaction. We describe 4 cases that illustrate benefits, particularly for children with DD and challenging behaviors, suggesting that asynchronous telemedicine may actually be superior to traditional in-office visits in some circumstances. Most parents expressed a high level of satisfaction with the program. Benefits identified include decreased stress to the child and the parents as well as increasing the likelihood of a successful medical examination due to greater cooperation by the child. Visits using asynchronous or "store and forward" telemedicine technology may be superior in some situations by allowing the visit to be performed at a pace that can be adjusted to the needs of the child with DD. More research in the use of asynchronous telemedicine for children and youth with DD, particularly for children with DD and challenging behaviors, is needed.

Multimotor Transport in a System of Active and Inactive Kinesin-1 Motors

PubMed Central

Scharrel, Lara; Ma, Rui; Schneider, René; Jülicher, Frank; Diez, Stefan

2014-01-01

Long-range directional transport in cells is facilitated by microtubule-based motor proteins. One example is transport in a nerve cell, where small groups of motor proteins, such as kinesins and cytoplasmic dynein, work together to ensure the supply and clearance of cellular material along the axon. Defects in axonal transport have been linked to Alzheimer’s and other neurodegenerative diseases. However, it is not known in detail how multimotor-based cargo transport is impaired if a fraction of the motors are defective. To mimic impaired multimotor transport in vitro, we performed gliding motility assays with varying fractions of active kinesin-1 motors and inactive kinesin-1 motor mutants. We found that impaired transport manifests in multiple motility regimes: 1), a fast-motility regime characterized by gliding at velocities close to the single-molecule velocity of the active motors; 2), a slow-motility regime characterized by gliding at close-to zero velocity or full stopping; and 3), a regime in which fast and slow motilities coexist. Notably, the transition from the fast to the slow regime occurred sharply at a threshold fraction of active motors. Based on single-motor parameters, we developed a stochastic model and a mean-field theoretical description that explain our experimental findings. Our results demonstrate that impaired multimotor transport mostly occurs in an either/or fashion: depending on the ratio of active to inactive motors, transport is either performed at close to full speed or is out of action. PMID:25028878

Area/latency optimized early output asynchronous full adders and relative-timed ripple carry adders.

PubMed

Balasubramanian, P; Yamashita, S

2016-01-01

This article presents two area/latency optimized gate level asynchronous full adder designs which correspond to early output logic. The proposed full adders are constructed using the delay-insensitive dual-rail code and adhere to the four-phase return-to-zero handshaking. For an asynchronous ripple carry adder (RCA) constructed using the proposed early output full adders, the relative-timing assumption becomes necessary and the inherent advantages of the relative-timed RCA are: (1) computation with valid inputs, i.e., forward latency is data-dependent, and (2) computation with spacer inputs involves a bare minimum constant reverse latency of just one full adder delay, thus resulting in the optimal cycle time. With respect to different 32-bit RCA implementations, and in comparison with the optimized strong-indication, weak-indication, and early output full adder designs, one of the proposed early output full adders achieves respective reductions in latency by 67.8, 12.3 and 6.1 %, while the other proposed early output full adder achieves corresponding reductions in area by 32.6, 24.6 and 6.9 %, with practically no power penalty. Further, the proposed early output full adders based asynchronous RCAs enable minimum reductions in cycle time by 83.4, 15, and 8.8 % when considering carry-propagation over the entire RCA width of 32-bits, and maximum reductions in cycle time by 97.5, 27.4, and 22.4 % for the consideration of a typical carry chain length of 4 full adder stages, when compared to the least of the cycle time estimates of various strong-indication, weak-indication, and early output asynchronous RCAs of similar size. All the asynchronous full adders and RCAs were realized using standard cells in a semi-custom design fashion based on a 32/28 nm CMOS process technology.

Refining an Asynchronous Telerehabilitation Platform for Speech-Language Pathology: Engaging End-Users in the Process

PubMed Central

Hill, Annie J.; Breslin, Hugh M.

2016-01-01

Asynchronous telerehabilitation in which computer-based interventions are remotely monitored and adapted offline is an emerging service delivery model in the rehabilitation of communication disorders. The asynchronous nature of this model may hold a benefit over its synchronous counterpart by eliminating scheduling issues and thus improving efficiency in a healthcare landscape of constrained resource allocation. The design of asynchronous telerehabilitation platforms should therefore ensure efficiency and flexibility. The authors have been engaged in a program of research to develop and evaluate an asynchronous telerehabilitation platform for use in speech-language pathology. eSALT is a novel asynchronous telerehabilitation platform in which clinicians design and individualize therapy tasks for transfer to a client's mobile device. An inbuilt telerehabilitation module allows for remote monitoring and updating of tasks. This paper introduces eSALT and reports outcomes from an usability study that considered the needs of two end-user groups, people with aphasia and clinicians, in the on-going refinement of eSALT. In the study participants with aphasia were paired with clinicians who used eSALT to design and customize therapy tasks. After training on the mobile device the participants engaged in therapy at home for a period of 3 weeks, while clinicians remotely monitored and updated tasks. Following the home trial, participants, and clinicians engaged in semi-structured interviews and completed surveys on the usability of eSALT and their satisfaction with the platform. Content analysis of data involving five participants and three clinicians revealed a number of usability themes including ease of use, user support, satisfaction, limitations, and potential improvements. These findings were translated into a number of refinements of the eSALT platform including the development of a client interface for use on the Apple iPad®, greater variety in feedback options to both the participant and clinician, automatic transfer of results to the clinician, and expansion of the task template list. This research highlights the importance of including end-users in the process of technology refinement, in order to ensure effective and efficient use of the technology. Future directions for research are discussed including clinical trials in which the effectiveness of and adherence to intervention protocols using asynchronous telerehabilitation are examined. PMID:28066211

Rapid Feedforward Inhibition and Asynchronous Excitation Regulate Granule Cell Activity in the Mammalian Main Olfactory Bulb

PubMed Central

Burton, Shawn D.

2015-01-01

Granule cell-mediated inhibition is critical to patterning principal neuron activity in the olfactory bulb, and perturbation of synaptic input to granule cells significantly alters olfactory-guided behavior. Despite the critical role of granule cells in olfaction, little is known about how sensory input recruits granule cells. Here, we combined whole-cell patch-clamp electrophysiology in acute mouse olfactory bulb slices with biophysical multicompartmental modeling to investigate the synaptic basis of granule cell recruitment. Physiological activation of sensory afferents within single glomeruli evoked diverse modes of granule cell activity, including subthreshold depolarization, spikelets, and suprathreshold responses with widely distributed spike latencies. The generation of these diverse activity modes depended, in part, on the asynchronous time course of synaptic excitation onto granule cells, which lasted several hundred milliseconds. In addition to asynchronous excitation, each granule cell also received synchronous feedforward inhibition. This inhibition targeted both proximal somatodendritic and distal apical dendritic domains of granule cells, was reliably recruited across sniff rhythms, and scaled in strength with excitation as more glomeruli were activated. Feedforward inhibition onto granule cells originated from deep short-axon cells, which responded to glomerular activation with highly reliable, short-latency firing consistent with tufted cell-mediated excitation. Simulations showed that feedforward inhibition interacts with asynchronous excitation to broaden granule cell spike latency distributions and significantly attenuates granule cell depolarization within local subcellular compartments. Collectively, our results thus identify feedforward inhibition onto granule cells as a core feature of olfactory bulb circuitry and establish asynchronous excitation and feedforward inhibition as critical regulators of granule cell activity. SIGNIFICANCE STATEMENT Inhibitory granule cells are involved critically in shaping odor-evoked principal neuron activity in the mammalian olfactory bulb, yet little is known about how sensory input activates granule cells. Here, we show that sensory input to the olfactory bulb evokes a barrage of asynchronous synaptic excitation and highly reliable, short-latency synaptic inhibition onto granule cells via a disynaptic feedforward inhibitory circuit involving deep short-axon cells. Feedforward inhibition attenuates local depolarization within granule cell dendritic branches, interacts with asynchronous excitation to suppress granule cell spike-timing precision, and scales in strength with excitation across different levels of sensory input to normalize granule cell firing rates. PMID:26490853

48 CFR 47.305-9 - Commodity description and freight classification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... freight classification. 47.305-9 Section 47.305-9 Federal Acquisition Regulations System FEDERAL... Commodity description and freight classification. (a) Generally, the freight rate for supplies is based on the rating applicable to the freight classification description published in the National Motor...

Transportation Fuels Markets, Midwest and Rocky Mountain

EIA Publications

2017-01-01

A new study commissioned by the U.S. Energy Information Administration (EIA), finds that changes in North American energy markets over the past decade have strengthened the supply of transportation fuels including motor gasoline, distillates, and jet fuel in the Midwest and Rocky Mountain regions.

Bioindustry Creates Green Jobs

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

2013-07-01

The U.S. bioindustry is expanding rapidly in response to the need for a near-term alternative to liquid petroleum fuels. The Energy Independence and Security Act of 2007 (EISA) requires that renewable fuels collectively supply at least 36 billion gallons of U.S. motor fuels by 2022.

49 CFR 535.4 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF TRANSPORTATION MEDIUM- AND HEAVY-DUTY VEHICLE FUEL EFFICIENCY PROGRAM § 535.4 Definitions. The... energy for the motor is supplied by a fuel cell. Fuel efficiency means the amount of work performed for... other than a conventional battery system or conventional flywheel. Supplemental electrical batteries and...

F1 style MGU-H applied to the turbocharger of a gasoline hybrid electric passenger car

NASA Astrophysics Data System (ADS)

Boretti, Albert

2017-12-01

We consider a turbocharged gasoline direct injection (DI) engine featuring a motor-generator-unit (MGU-H) fitted on the turbocharger shaft. The MGU-H receives or delivers energy to the same energy storage (ES) of the hybrid power unit that comprises a motor-generator unit on the driveline (MGU-K) in addition to the internal combustion engine (ICE). The energy supply from the ES is mostly needed during sharp accelerations to avoid turbo-lag, and to boost torque at low speeds. At low speeds, it also improves the ratio of engine crankshaft power to fuel flow power, as well as the ratio of engine crankshaft plus turbocharger shaft power to fuel flow power. The energy supply to the ES is possible at high speeds and loads, where otherwise the turbine could have been waste gated, and during decelerations. This improves the ratio of engine crankshaft plus turbocharger shaft power to fuel flow power.

A Manufacturing Cost and Supply Chain Analysis of SiC Power Electronics Applicable to Medium-Voltage Motor Drives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Horowitz, Kelsey; Remo, Timothy; Reese, Samantha

Wide bandgap (WBG) semiconductor devices are increasingly being considered for use in certain power electronics applications, where they can improve efficiency, performance, footprint, and, potentially, total system cost compared to systems using traditional silicon (Si) devices. Silicon carbide (SiC) devices in particular -- which are currently more mature than other WBG devices -- are poised for growth in the coming years. Today, the manufacturing of SiC wafers is concentrated in the United States, and chip production is split roughly equally between the United States, Japan, and Europe. Established contract manufacturers located throughout Asia typically carry out manufacturing of WBG powermore » modules. We seek to understand how global manufacturing of SiC components may evolve over time by illustrating the regional cost drivers along the supply chain and providing an overview of other factors that influence where manufacturing is sited. We conduct this analysis for a particular case study where SiC devices are used in a medium-voltage motor drive.« less

"Fast" and "slow" skeleto-fusimotor innervation in cat tenuissimus spindles; a study with the glycogen-depletion method.

PubMed

Jami, L; Lan-Couton, D; Malmgren, K; Petit, J

1978-07-01

The glycogen-depletion method was used to investigate the motor supply to tenuissimus with respect to the presence of fast beta axons and to assess the total proportion of both fast and slow beta-innervated spindles in this muscle. In a first series of 5 expts., groups of motor axons with conduction velocities higher than 85 m/s were repetitively stimulated so as to produce glycogen depletion in the muscle fibres they innervated. The whole muscle was then quick-frozen, serially cut, stained to demonstrate glycogen and examined for intrafusal glycogen depletion. Zones of glycogen depletion were found in 16 of the 46 examined spindles; they were most frequently located in the longest of the chain intrafusal muscle fibres. Since it is known that there are no purely fusimotor axons to tenuissimus with conduction velocities above 50 m/s, it was concluded that beta axons are present among the fastest axons to this muscle. In a second series of 5 expts. as many motor axons as possible with conduction velocities above 60 m/s were stimulated. Zones of glycogen depletion were found in 19 of the 47 examined spindles. They affected chain fibres in about half of the instances and bag1 fibers in the others. As this latter location is characteristic of slow dynamic beta axons, it was concluded that both slow and fast beta axons occur regularly in the motor supply to tenuissimus. beta-innervation is present in at least 40% of tenuissimus spindles with almost no convergence of fast and slow beta axons onto the same spindle.

Precision electronic speed controller for an alternating-current

DOEpatents

Bolie, Victor W.

1988-01-01

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

Driver electronics design and control for a total artificial heart linear motor.

PubMed

Unthan, Kristin; Cuenca-Navalon, Elena; Pelletier, Benedikt; Finocchiaro, Thomas; Steinseifer, Ulrich

2018-01-27

For any implantable device size and efficiency are critical properties. Thus, a linear motor for a Total Artificial Heart was optimized with focus on driver electronics and control strategies. Hardware requirements were defined from power supply and motor setup. Four full bridges were chosen for the power electronics. Shunt resistors were set up for current measurement. Unipolar and bipolar switching for power electronics control were compared regarding current ripple and power losses. Here, unipolar switching showed smaller current ripple and required less power to create the necessary motor forces. Based on calculations for minimal power losses Lorentz force was distributed to the actor's four coils. The distribution was determined as ratio of effective magnetic flux through each coil, which was captured by a force test rig. Static and dynamic measurements under physiological conditions analyzed interaction of control and hardware and all efficiencies were over 89%. In conclusion, the designed electronics, optimized control strategy and applied current distribution create the required motor force and perform optimal under physiological conditions. The developed driver electronics and control offer optimized size and efficiency for any implantable or portable device with multiple independent motor coils. Graphical Abstract ᅟ.

Participation in Asynchronous Online Discussion Forums Does Improve Student Learning of Gross Anatomy

ERIC Educational Resources Information Center

Green, Rodney A.; Farchione, Davide; Hughes, Diane L.; Chan, Siew-Pang

2014-01-01

Asynchronous online discussion forums are common in blended learning models and are popular with students. A previous report has suggested that participation in these forums may assist student learning in a gross anatomy subject but it was unclear as to whether more academically able students post more often or whether participation led to…

Online-BSEE (Online Bachelor of Science in Electrical Engineering): An Asynchronous Online Electrical Engineering Degree Program with Laboratory

ERIC Educational Resources Information Center

Tang, Wendy; Westgate, Charles; Liu, Pao-Lo; Gouzman, Michael

2014-01-01

The Online Bachelor of Science in Electrical Engineering is a collaborative effort among three University Centers at SUNY (State University of New York), namely Stony Brook, Binghamton, and Buffalo. The program delivers the complete electrical engineering curriculum at the bachelor level to students online and asynchronously. Students, however,…

Reversible logic gates on Physarum Polycephalum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumann, Andrew

2015-03-10

In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.