Inefficient Motor Research Articles

Comparative Review of Three PWM Approach On 3-Φ VSI Fed with Induction Motor Drive

Induction motor demand is increasing day by day with increasing demand an essential requirement arises too inefficient motor controlling method. A comparison study of three diverse Pulse width modulation (PWM) techniques of 3-ϕ inverter for better performance of induction motor is presented here using MATLAB/Simulink. Sinusoidal PWM, Third Harmonic injected PWM (THIPWM), Space Vector PWM (SVPWM) techniques simulation is show here, Motor parameter like speed vs time, torque vs time, Output voltage (THD), Output current (THD) of an inverter was observed by changing the carrier frequency and motor drive load. Simulation result shows that SVPWM flaunt better performance comparing other PWM technique.

Modeling stock, material and environmental impacts of circular economy product policies. Trade-offs between early replacement and repair of electric motors

New modeling challenges are accompanying the shift in EU product policy toward an increased focus on circular economy aspects. Combined material flow analysis and life cycle assessment can play an important role in assessing the impact of such policies. A flexible model has been developed that is suitable for the ex-ante impact assessment of the material flows and environmental impacts of a range of circular economy product policies, extending an established approach. The model uses a layered approach, in which material and environmental impacts are derived from product flows via a product database that defines physical properties for product variants. Combined with a stock model, the impact of policy interventions on the whole market can be assessed over time and per life cycle stage. We apply this model in a theoretical case study on electric motors, which compares early replacement of inefficient motors and motor repair with a base case.

Impaired Neuromotor Control During Gait in Concussed Adolescents-A Frequency Analysis.

Disruptions in gait function are common after concussion in adolescents; however, the neuromotor control deficits driving these gait disruptions are not well known. Fifteen concussed (age mean [SD]): 17.4 [0.6], 13 females, days since injury: 26.3 [9.9]) and 17 uninjured (age: 18.0 [0.7], 10 females) adolescents completed 3 trials each of single-task gait and dual-task gait (DT). During DT, participants simultaneously walked while completing a serial subtraction task. Gait metrics and variability in instantaneous mean frequency in lower extremity muscles were captured by inertial sensors and surface electromyography, respectively. A 2-way analysis of covariance was used to compare gait metrics across groups and conditions. Functional principal components analysis was used to identify regions of variability in instantaneous mean frequency curves. Functional principal component scores were compared across groups using a Welch statistic. Both groups displayed worse performance on gait metrics during DT condition compared to single-task, with no differences between groups (P < .001). Concussed adolescents displayed significantly greater instantaneous mean frequency, indicated by functional principal component 1, in the tibialis anterior, biceps femoris, and semitendinosus (P < .05) during single-task and DT compared with uninjured adolescents. Our observations suggest that concussed adolescents display inefficient motor unit recruitment lasting longer than 2weeks following injury, regardless of the addition of a secondary task.

A systematic review of ironic effects of motor task performance under pressure: The past 25 years

ABSTRACT Wegner's theory of ironic processes of mental control emphasizes how the implementation of cognitive load-induced avoidant instructions can cause inefficient motor cognition in sports, thereby inducing so-called ironic effects where an individual—ironically—does precisely what s(he) intended not to do. This systematic review synthesizes relevant existing research and evaluates the effectiveness of experimental manipulations and cognitive load measurements for investigating ironic effects on motor task performance under pressure conditions. This review identified twenty-four empirical studies published before January 2022, including studies with experimental (21%) and quasi-experimental (79%) within- and between-subject designs. The most common reported pressure (i.e., cognitive load) manipulations fell into two categories: anxiety (77%) and dual-task (33%) techniques. The review also identified positive action-oriented instructional interventions to reduce ironic errors. Although most reported findings supported Wegner's assumptions about ironic performance effects, the review also identified inconclusive evidence (8%), which indicates a need for more research with a greater focus on: robust experimental design; the inclusion of competitive stressors; expert athletes; elite athletes; and intervention-based studies. These additions will clarify the mechanisms of ironic effects and assist in the development of interventional programs to diminish the likelihood of ironic effects in sports performance.

Perspectives on Electric Motor Market Transformation for a Net Zero Carbon Economy

Energy efficiency is one of the most powerful strategies to mitigate the impacts of climate change by reducing energy demand, which in turn reduces the emissions of Green House Gases (GHG), as well as reducing the burden on the supply side renewable generation expansion. Because electric motors systems represent such a large share of the overall electricity consumption (over 50%), large savings potential could be made available by the use of energy-efficient motor systems both in new installations and by accelerating the replacement of old inefficient motors. Since electric motors are very reliable, their lifetime is long (according to recent studies it may exceed 20 years) which translates into a very inefficient existing stock despite worldwide policy efforts. This paper analyzes the current efficiency of the installed stock and the causes for its low efficiency, possible policy options to increase its the efficiency, the role of new technologies and improvements possible by targeting the entire motor system at the time of motor replacement. The paper presents an innovative analysis of the estimated impact of increasing the uptake of high-efficiency motors and motor systems; effective policies could translate into 100 TWh/year in the European Union if additional measures, such as addressing oversizing, proper controls (VSDs) and digitisation, are also implemented. If similar measures were adopted globally, the savings triggered could be at least tenfold reaching over 1000 TWh/year.

DOES BRAIN ACTIVATION DURING FUNCTIONAL MOVEMENT TASKS DIFFERENTIATE BETWEEN GOOD AND BAD MOVERS? AN INTEGRATED NEUROIMAGING ASSESSMENT OF MOTOR CONTROL IN YOUNG ATHLETES

Background:Aberrant frontal and sagittal plane knee motor control biomechanics contribute to increased anterior cruciate ligament (ACL) injury risk. Emergent data further indicates alterations in brain function may underlie ACL injury high risk biomechanics and primary injury. However, technical limitations have limited our ability to assess direct linkages between maladaptive biomechanics and brain function.Hypothesis/Purpose:(1) Increased frontal plane knee range of motion would associate with altered brain activity in regions important for sensorimotor control and (2) increased sagittal plane knee motor control timing error would associate with altered activity in sensorimotor control brain regions.Methods:Eighteen female high-school basketball and volleyball players (14.7 ± 1.4 years, 169.5 ± 7 cm, 65.8 ± 20.5 kg) underwent brain functional magnetic resonance imaging (fMRI) while performing a bilateral, combined hip, knee, and ankle flexion/extension movements against resistance (i.e., leg press) Figure 1(a). The participants completed this task to a reference beat of 1.2 Hz during four movement blocks of 30 seconds each interleaved in between 5 rest blocks of 30 seconds each. Concurrent frontal and sagittal plane range of motion (ROM) kinematics were measured using an MRI-compatible single camera motion capture system.Results:Increased frontal plane ROM was associated with increased brain activity in one cluster extending over the occipital fusiform gyrus and lingual gyrus (p = .003, z > 3.1). Increased sagittal plane motor control timing error was associated with increased brain activity in multiple clusters extending over the occipital cortex (lingual gyrus), frontal cortex, and anterior cingulate cortex (p < .001, z > 3.1); see Figure 1 (b).Conclusion:The associations of increased knee frontal plane ROM and sagittal plane timing error with increased activity in regions that integrate visuospatial information may be indicative of an increased propensity for knee injury biomechanics that are, in part, driven by reduced spatial awareness and an inability to adequately control knee abduction motion. Increased activation in these regions during movement tasks may underlie an impaired ability to control movements (i.e., less neural efficiency), leading to compromised knee positions during more complex sports scenarios. Increased activity in regions important for cognition/attention associating with motor control timing error further indicates a neurologically inefficient motor control strategy.Figure 1:(a) Participant positioned in the leg press apparatus during fMRI and instrumented with MRI-compatible motion analysis markers (b) Brain activity associated with poor knee frontal plane (green) and sagittal plane (red) kinematics.

Jet–Accretion System in the Nearby mJy Radio Galaxies

Abstract It is generally thought that FRII radio galaxies host thin optically thick disks, while FRIs are powered by advection-dominated accretion flows. Sources with an efficient engine are optically classified as high-excitation radio galaxies (HERGs) and those with an inefficient motor as low-excitation radio galaxies (LERGs). Recently, the study of radio galaxies down to mJy fluxes has cast serious doubts on the LERG-FRI and HERG-FRII correspondence, revealing that many LERGs show FRII radio morphologies. The FR catalogs recently compiled by Capetti et al. and Baldi et al. have allowed us to explore this issue in the local (z ≤ 0.15) mJy universe. Our statistical study shows that the majority of nearby mJy objects are in a late stage of their life. FRII-LERGs appear more similar to the old FRI-LERGs than to the young FRII-HERGs. FRII-LERGs may be aged HERGs that, having exhausted their cold fuel, have changed their accretion regime or are a separate LERG class particularly efficient in launching jets. Exploiting the empirical relations that convert L [O III] and L 1.4 GHz into accretion power and jet kinetic power, respectively, we observed that LERGs with similar masses and accretion rates seem to expel jets of different powers. We speculate that intrinsic differences related to the black hole properties (spin and magnetic field at its horizon) can determine the observed spread in jet luminosity. In this view, FRII-LERGs should have the fastest spinning black holes and/or the most intense magnetic fluxes. On the contrary, compact LERGs (i.e., FR0s) should host extremely slow black holes and/or weak magnetic fields.

Children with developmental coordination disorder show altered functional connectivity compared to peers

Developmental Coordination Disorder (DCD) is a neurodevelopmental disorder that affects a child’s ability to learn motor skills and participate in self-care, educational, and leisure activities. The cause of DCD is unknown, but evidence suggests that children with DCD have atypical brain structure and function. Resting-state MRI assesses functional connectivity by identifying brain regions that have parallel activation during rest. As only a few studies have examined functional connectivity in this population, our objective was to compare whole-brain resting-state functional connectivity of children with DCD and typically-developing children. Using Independent Component Analysis (ICA), we compared functional connectivity of 8–12 year old children with DCD (N = 35) and typically-developing children (N = 23) across 19 networks, controlling for age and sex. Children with DCD demonstrate altered functional connectivity between the sensorimotor network and the posterior cingulate cortex (PCC), precuneus, and the posterior middle temporal gyrus (pMTG) (p < 0.0001). Previous evidence suggests the PCC acts as a link between functionally distinct networks. Our results indicate that ineffective communication between the sensorimotor network and the PCC might play a role in inefficient motor learning seen in DCD. The pMTG acts as hub for action-related information and processing, and its involvement could explain some of the functional difficulties seen in DCD. This study increases our understanding of the neurological differences that characterize this common motor disorder.

Limited Pre-Speech Auditory Modulation in Individuals Who Stutter: Data and Hypotheses.

PurposeWe review and interpret our recent series of studies investigating motor-to-auditory influences during speech movement planning in fluent speakers and speakers who stutter. In those studies, we recorded auditory evoked potentials in response to probe tones presented immediately prior to speaking or at the equivalent time in no-speaking control conditions. As a measure of pre-speech auditory modulation (PSAM), we calculated changes in auditory evoked potential amplitude in the speaking conditions relative to the no-speaking conditions. Whereas adults who do not stutter consistently showed PSAM, this phenomenon was greatly reduced or absent in adults who stutter. The same between-group difference was observed in conditions where participants expected to hear their prerecorded speech played back without actively producing it, suggesting that the speakers who stutter use inefficient forward modeling processes rather than inefficient motor command generation processes. Compared with fluent participants, adults who stutter showed both less PSAM and less auditory–motor adaptation when producing speech while exposed to formant-shifted auditory feedback. Across individual participants, however, PSAM and auditory–motor adaptation did not correlate in the typically fluent group, and they were negatively correlated in the stuttering group. Interestingly, speaking with a consistent 100-ms delay added to the auditory feedback signal–normalized PSAM in speakers who stutter, and there no longer was a between-group difference in this condition.ConclusionsCombining our own data with human and animal neurophysiological evidence from other laboratories, we interpret the overall findings as suggesting that (a) speech movement planning modulates auditory processing in a manner that may optimize its tuning characteristics for monitoring feedback during speech production and, (b) in conditions with typical auditory feedback, adults who stutter do not appropriately modulate the auditory system prior to speech onset. Lack of modulation of speakers who stutter may lead to maladaptive feedback-driven movement corrections that manifest themselves as repetitive movements or postural fixations.

Motor planning with and without motor imagery in children with Developmental Coordination Disorder

Children with Developmental Coordination Disorder (DCD) demonstrate inefficient motor planning ability with a tendency to opt for non-optimal planning strategies. Motor imagery can provide an insight to this planning inefficiency, as it may be a strategy for improving motor planning and thereby motor performance for those with DCD. In this study, we investigated the prevalence of end-state-comfort (ESC) and the minimal rotation strategy using a grip selection task in children with DCD with and without motor imagery instructions. Boys with (n = 14) and without DCD (n = 18) aged 7–12 years completed one, two and three colour sequences of a grip selection (octagon) task. Two conditions were examined; a Motor Planning (MP) condition requiring only the performance of the task and a Motor Imagery and Planning (MIP) condition, which included an instruction to imagine performing the movement before execution. For the MP condition, children with DCD ended fewer trials in ESC for the one (p = 0.001) and two colour (p = 0.002) sequences and used a minimal rotation strategy more often than those without DCD. For the MIP condition, the DCD group significantly increased their use of the ESC strategy for the one colour sequences (p = 0.014) while those without DCD improved for the two colour (p = 0.008) sequences. ESC level of the DCD group on the MIP condition was similar to those without DCD at baseline for all colour sequences. Motor imagery shows potential as a strategy for improving motor planning in children with DCD. Implications and limitations are discussed.

A New Field Test Method for Determining Energy Efficiency of Induction Motor

Electric motors and the drive systems approximately consume half of the global electricity consumption. In the European Union (EU), electric motors and the drive systems are estimated to account for about 70% of all industrial electricity consumption. Therefore, mandatory applications accrue from the legislation of governments or unions like the EU for customs and market surveillance or eco-design requirements. The mandatory applications and the global market size find out the necessity of efficiency measurement. There are several compliance and precompliance efficiency test methods in the literature. The compliance tests should execute reliable, accurate, and reproducible results. The purpose of this paper is to define a simple field method that will be used for measuring and determining in-service efficiency at industrial conditions. The proposed method in this paper is an inexpensive and easy method that would help to energy managers and engineers to make correct decision in replacing inefficient motors with efficient and new ones. In this paper, a novel induction motor-efficiency model function has been proposed based on the International Electrotechnical Commission 60034-2-1 standard equations, and a new field test procedure has been used in efficiency estimation. The new efficiency model function variables and constants are determined from the regression analysis, which depends on 86 tests of 437 different load points’ efficiency data. Furthermore, the proposed field test procedure, equations, and compliance test methods are tested on a sample motor in laboratory, and the results are compared to each other.

Induction Motor Parameter Estimation Using Sparse Grid Optimization Algorithm

Inaccurate motor parameters can lead to an inefficient motor control. Although several motor estimation methods have been utilized to estimate motor parameters, it is still challenging to ensure a good level of confidence in the estimation. In this paper, we propose a novel offline induction motor parameter estimation method based on sparse grid optimization algorithm. The estimation is achieved by matching the response of machines mathematical model with recorded stator current and voltage signals. This approach is noninvasive as it uses external measurements, resulting in reduced system complexity and cost. A globally optimal point was found by sampling on the sparse grid, which was created using the hyperbolic cross points and additional heuristics. This has resulted in reducing the total number of search points, and provided the best match between the mathematical model and measurement data. The estimated motor parameters can be further refined by using any local search method. The experimental results indicate a very good agreement between estimated values and reference values.

Psychological pressure facilitates corticospinal excitability: Motor preparation processes and EMG activity in a choice reaction task

The effects of psychological pressure on corticospinal excitability and muscular activity were investigated in a two-choice reaction task that involved voluntary right index finger movements. In order to induce pressure, participants were given instructions that combined a performance-contingent cash reward, a penalty, and performance comparisons. Following practice, 11 participants performed 40 non-pressure and 40 pressure trials. Results showed successful stress induction, as indexed by significant increases in state anxiety, pulse rate, and galvanic skin response under pressure. Significant increases in the amplitude of the motor evoked potential of the right abductor pollicis brevis (APB) occurred under pressure. The maximum EMG amplitudes of APB and the first dorsal interosseous (FDI) muscle also increased significantly under pressure. These results suggest that descending excitatory volleys in the corticospinal motor tract during the motor preparation processes and peripheral motor unit activities in the reaction task are both separately excited by stress responses under pressure. Reaction times measured by EMG onset of the FDI were unchanged in accordance with corticospinal and EMG excitations under pressure, indicating generation of inefficient motor control energy for movement output.

Increased Intrasubject Variability in Boys with ADHD Across Tests of Motor and Cognitive Control

Increased intrasubject variability (ISV), or short-term, within-person fluctuations in behavioral performance is consistently found in Attention-Deficit/Hyperactivity Disorder (ADHD). ADHD is also associated with impairments in motor control, particularly in boys. The results of the few studies that have examined variability in self-generated motor output in children with ADHD have been inconsistent. The current study examined variability in motor control during a finger sequencing task among boys with and without ADHD as well as the relationship between intrasubject variability during motor and cognitive control tasks. Changes in performance over the course of the task and associations with ADHD symptom domains were also examined to elucidate the nature of impaired motor control in children with ADHD. Fifty-one boys (ages 8 to 12years) participated in the study, including 28 boys with ADHD and 23 typically developing (TD) boys. Participants completed a finger sequencing task and a Go/No-Go task providing multiple measures of response speed and variability. Boys with ADHD were slower and more variable in both intertap interval on the finger sequencing task and reaction time on the Go/No-Go task, with measures of speed and variability correlated across the two tasks. For the entire cohort, the only unique predictor of parent ratings of hyperactive-impulsive symptoms was variability in intertap interval during finger sequencing, whereas inattentive symptoms were only predicted by reaction time variability on the Go/No-Go task. These findings suggest that inefficient motor control is implicated in the pathophysiology of ADHD, particularly in regards to developmentally inappropriate levels of hyperactivity and impulsivity.

An accurate and economical approach for induction motor field efficiency estimation using bacterial foraging algorithm

As the demand of electrical energy increases, it is vital to replace inefficient motors with new energy efficient ones. The first step towards achieving this goal is to estimate the existing motors efficiencies accurately to determine how much energy saving will be achieved by using energy efficient motors. This paper proposes an economical and accurate approach for motor field efficiency estimation using bacterial foraging algorithm. The approach relies on the measurement of the stator current, stator voltage, input power, stator resistance and rotor speed of the motor without conducting no-load and locked-rotor tests. The BF algorithm is used to determine the equivalent circuit parameters of the motor. The efficiency is then estimated using these parameters. The advantages of the proposed method over the existing methods are simple procedure, efficiency can be estimated accurately without conducting any invasive tests and inexpensive. The approach has been tested on a 5 HP motor and the results are compared with particle swarm optimization method, immune algorithm method, torque gauge method, equivalent circuit method, slip method, current method and segregated loss method. The results demonstrate that the proposed approach can accurately estimate the field efficiency of motor. Accordingly, it is suitable for conducting energy audits and management of the motor.

Teaching &amp; Learning Guide for: Religious Environmentalism in the West

Teaching &amp; Learning Guide for: Religious Environmentalism in the West

The use of a tool requires its incorporation into the movement: Evidence from stick-pointing in apraxia

When using a tool, the agent has to control the movement of this implement to perform an efficient action. While perceptual assimilation of a tool has been shown to occur during its use, the incorporation of an implement into the control of movements has received little attention. Here, we investigated the relation between the ability to integrate an object into motor coordination, and tool use. Apraxic patients impaired for familiar tool use were asked to point at targets located at various distances using either their finger, or two sticks of different lengths (23 and 53 cm). Left-brain damaged patients without apraxia participated as controls. Movement kinematics were analysed, with a particular focus on the working point (WP) of the action, defined as the tip of the finger or stick. Control patients produced movements with similar kinematic characteristics in all conditions, and were slightly less accurate with the sticks than with their finger. In contrast, more than half of the apraxics (6/10) showed various degrees of impairment when pointing with the sticks, manifested by deviant and inefficient motor strategies and abnormally large errors. In light of previous work in motor control and kinematics, it is argued that this reflects a deficit in anticipatively controlling a WP located in the stick, that is, in integrating the stick into the movement. We propose that this impairment might be related to dysfunction of the processes involved in dynamic body representation, which needs to be extended to include the tool to be used. Future directions are discussed to further characterize the relation between object incorporation and tool use, and its relevance for understanding apraxia and the neural bases of tool use.

Oil consumption and CO 2 emissions in China's road transport: current status, future trends, and policy implications

With the rapid economic growth in China, the Chinese road transport system is becoming one of the largest and most rapidly growing oil consumers in China. This paper attempts to present the current status and forecast the future trends of oil demand and CO 2 emissions from the Chinese road transport sector and to explore possible policy measures to contain the explosive growth of Chinese transport oil consumption. A bottom-up model was developed to estimate the historical oil consumption and CO 2 emissions from China's road transport sector between 1997 and 2002 and to forecast future trends in oil consumption and CO 2 emissions up to 2030. To explore the importance of policy options of containing the dramatic growth in Chinese transport oil demand, three scenarios regarding motor vehicle fuel economy improvements were designed in predicting future oil use and CO 2 emissions. We conclude that China's road transportation will gradually become the largest oil consumer in China in the next two decades but that improvements in vehicle fuel economy have potentially large oil-saving benefits. In particular, if no control measures are implemented, the annual oil demand by China's road vehicles will reach 363 million tons by 2030. On the other hand, under the low- and high-fuel economy improvement scenarios, 55 and 85 million tons of oil will be saved in 2030, respectively. The scenario analysis suggests that China needs to implement vehicle fuel economy improvement measures immediately in order to contain the dramatic growth in transport oil consumption. The imminent implementation is required because (1) China is now in a period of very rapid growth in motor vehicle sales; (2) Chinese vehicles currently in the market are relatively inefficient; and (3) the turnover of a fleet of inefficient motor vehicles will take a long time.

An accurate low-cost method for determining electric motors efficiency for the purpose of plant energy management

As the cost of energy increases it is increasingly more important to remove inefficient motors from operation. The first step towards achieving this goal is to estimate accurately the existing motors' efficiencies to determine how much saving will be achieved by using more efficient motors. The problem with estimating. the efficiency of motors in the field is the practicality,and cost associated with measuring the output power. This paper describes the results of a very low cost and accurate method for determining the motor efficiency without the need for removing the motors and without the need for measuring the output power or torque. Test results indicate that the novel method has an accuracy of over 99%. As a result of the high accuracy it is possible to estimate the potential savings with great confidence.

Behavioural correlates of early‐treated congenital hypothyroidism

Parents' and teachers' ratings were used to evaluate the behavioural characteristics of children with early‐treated congenital hypothyroidism (CH). Comparisons were made between 63 children with early‐treated CH and 34 healthy controls at the ages of 7.5 and 9.5 y. Additional comparisons were made between the two largest CH subgroups (thyroid agenesis, thyroid dysgenesis) and controls. The most marked differences were found on the introversion cluster and the motor clumsiness scale within it. Children with CH, particularly those with thyroid agenesis, showed introversion and motor clumsiness rather than social negativity and inattention. It is suggested that this behavioural profile may well have its origins in the often‐reported inefficient motor behaviour of these children. Results are discussed in the light of recent findings suggesting an association between thyroid hormone problems and attention deficit hyperactivity disorder. Conclusion: Early‐treated CH is associated with introversion rather than with social negativity.