Motor Speed Changes Research Articles

Comparison of Neurocognitive Performance in Contact and Noncontact Nonconcussed High School Athletes Across a Two-Year Interval

ABSTRACTInvestigating short-term effects of subconcussive impacts on neurocognitive functioning, we employed a repeated measures multivariate model and regression-based measure to examine neurocognitive changes in 771 contact and noncontact high school athletes over a two-year period. Results reveal significant changes in Visual Motor Speed for both groups over a two-year period, with small effect sizes. According to regression-based measures, differences in contact sport athletes’ expected Time 2 performances were significant for Visual Motor Speed, also with minimal effects. Results do not conclusively implicate subconcussive hits as the offending factor in differences observed, with gender and sport-type possibly contributing to the small effects.

Video gaming in school children: How much is enough?

Despite extensive debate, the proposed benefits and risks of video gaming in young people remain to be empirically clarified, particularly as regards an optimal level of use. In 2,442 children aged 7 to 11 years, we investigated relationships between weekly video game use, selected cognitive abilities, and conduct-related problems. A large subgroup of these children (n = 260) was further examined with magnetic resonance imaging approximately 1 year later to assess the impact of video gaming on brain structure and function. Playing video games for 1 hour per week was associated with faster and more consistent psychomotor responses to visual stimulation. Remarkably, no further change in motor speed was identified in children playing >2 hours per week. By comparison, the weekly time spent gaming was steadily associated with conduct problems, peer conflicts, and reduced prosocial abilities. These negative implications were clearly visible only in children at the extreme of our game-playing distribution, with 9 hours or more of video gaming per week. At a neural level, changes associated with gaming were most evident in basal ganglia white matter and functional connectivity. Significantly better visuomotor skills can be seen in school children playing video games, even with relatively small amounts of use. Frequent weekly use, by contrast, was associated with conduct problems. Further studies are needed to determine whether moderate video gaming causes improved visuomotor skills and whether excessive video gaming causes conduct problems, or whether children who already have these characteristics simply play more video games. Ann Neurol 2016;80:424-433.

Upper extremity strength and motor speed in children with visual impairment following a 16-week yoga training program

BACKGROUND: Yoga’s benefits on various aspects of health for sighted children is substantially supported by the literature. This study aimed to extend those fidings to children with visual impairment. OBJECTIVE: The aim of the study was to measure changes in upper extremity strength and motor speed in children with visual impairment following 16-weeks of yoga training. METHODS: This was a two arm pre post, single blind, waitlist-controlled study. Eighty-three (yoga [n = 41], control [n = 42]) participants (aged 9–16 years) enrolled, 6 dropped out from the trial. Demographic characteristics were not significantly different between the two groups. The following variables: upper extremity muscle strength; elbow flexion and elbow extension, pinch strength and motor speed were evaluated bilaterally using a handheld dynamometer, pinch dynamometer and finger tapping board respectively at baseline and after the 16-week intervention. SPSS-20 was used for statistical analysis. RESULTS: Significant improvements in all variables ( P< 0.05) were observed in the yoga group for both limbs but no significant changes were observed in the control group. CONCLUSION: The study suggests that yoga may be considered an effective option to improve muscle strength and motor function in children with visual impairment.

A Fault Tolerant Control Structure for an Induction Motor Drive System

In this paper the Fault Tolerant (FT) vector controlled induction motor drive system is described and tested in various drive conditions. The influence of the rotor speed sensor faults on the properties of the analyzed drive are tested. Faults detection algorithms, based on different algorithms are developed and described. The results of the simulation carried out using the MATLAB/Sim Power System software are verified in experimental tests in Micro Lab Box DS 1202, in a wide range of motor speed changes. The proposed detection algorithms can be successfully applied in the Fault Tolerant Drive Systems (FTDS).

Implementation of Genetic Algorithm for Parameter Tuning of PID Controller in Three Phase Induction Motor Speed Control

Induction motor at low speeds has a tough speed setting sets the width of the range. This study tested by giving the load motor disorders to describe the condition. The method used for vector control system so that the resulting performance is good at setting the motor speed and torque. This method is used in setting the Proportional Integral Derivative (PID) Tuning parameter settings based on Genetic Algorithm (GA) to provide a dynamic response to changes in speed and load torque on the motor, so we get smoothness at any speed change and braking and maximum torque motors. Optimization function is required to obtain a new PID parameter values each input value changes or load disturbances, in terms of the initial determination of these parameters using Ziegler-Nichols method based on frequency response. Tests were performed at a speed of approximately 1800 rpm value rise time of about 10 seconds after generation added, at a rate of 1800 rpm rise time value of the average remains around 9 seconds, but slightly reduced the oscillations in the response, and the speed of approximately 1700 rpm rise time value of the average is 9 seconds. The test results show that GA-based PID controller has a good response in approximately 0.85% overshoot at the motor speed change and braking

캔드타입 전동워터펌프용 수중베어링의 특성분석

Article history: This paper presents characteristic analysis of underwater bearing for canned type electric water pump. Characteristic analysis of underwater bearing was performed using self-developed performance tester, which capable of torque change, noise change, motor speed change and abrasion loss test with respect to temperature change of underwater bearing. The performance tester can be monitored in real time by designing the control unit using the Labview program. The performance experiment was performed through comparison of the silicon carbide (SIC) and the carbon bearing. From the experiment results, performance of SIC bearing was better than carbon bearing at the abrasion and temperature experiment.

Driver behavior during bicycle passing maneuvers in response to a Share the Road sign treatment

The interaction of motorists and bicyclists, particularly during passing maneuvers, is an area of concern to the bicycle safety community as there is a general perception that motor vehicle drivers may not share the road effectively with bicyclists. This is a particular concern on road sections with centerline rumble strips where motorists are prone to crowd bicyclists during passing events. One potential countermeasure to address this concern is the use of a bicycle warning sign with a “Share the Road” plaque. This paper presents the results of a controlled field evaluation of this sign treatment, which involved an examination of driver behavior while overtaking bicyclists. A series of field studies were conducted concurrently on two segments of a high-speed, rural two-lane highway. These segments were similar in terms of roadway geometry, traffic volumes, and other relevant factors, except that one of the segments included centerline rumble strips while the other did not. A before-and-after study design was utilized to examine changes in motor vehicle lateral placement and speed at the time of the passing event as they relate to the presence of centerline rumble strips and the sign treatment. Centerline rumble strips generally shifted vehicles closer to the bicyclists during passing maneuvers, though the magnitude of this effect was marginal. The sign treatment was found to shift motor vehicles away from the rightmost lane positions, though the signs did not significantly affect the mean buffer distance between the bicyclists and passing motorists or the propensity of crowding events during passing. The sign treatment also resulted in a 2.5miles/h (4.0km/h) reduction in vehicle speeds. Vehicle type, bicyclist position, and the presence of opposing traffic were also found to affect lateral placement and speed selection during passing maneuvers.

Localized Electroosmosis (LEO) Induced by Spherical Colloidal Motors

Experimental data show that the speed of colloidal (catalytic) motors decreases as the size of the motor particles increases. However, previous electrokinetic models have shown that the colloidal motor speed for spheres is independent of size, at least for the case of infinitesimally thin double layers and reaction-limited catalysis. Although a size dependence of motor speed has been calculated for diffusion-limited catalysis, most motor experiments are done in the reaction-limited regime. This apparent contradiction led us to examine how motor speed (U) changes with distance (δ) from a wall, starting from the usual electrokinetic equations. A key finding is that interactions between a colloidal motor and a nearby wall produce a localized electroosmotic (LEO) flow field that can significantly alter the motor speed near the wall. Because large motor particles typically settle closer to the wall than small motors, LEO thus provides at least one explanation of the size dependence of motor speed. Furthermore, LEO provides a new method of creating flow fields in capillaries and microchannels.

On mechanical governors for electric motors

In this work I propose a mechanism whereby a Watt mechanical governor can be used in the context of electric motor control. The motor considered is the shunt or parallel dc motor, in which flux weakening is used as a speed regulation strategy. Connection of the governorballs to a variable resistor in series with the stator circuit results in automatic flux weakening as the motor speed changes, and this phenomenon can be used to alter the torque-speed characteristics of the motor in the desired manner. After demonstrating the details of this process under the steady state assumption, I construct the dynamic model for the combined motor–governor arrangement. The system is a set of coupled nonlinear differential equations. Linearization about the fixed point yields the conditions for stable operation and also shows the possibility of a Hopf bifurcation. I introduce a self-consistent procedure for finding the characteristics of the limit cycle. The existence of this limit cycle is supported by numerical simulations.

The Neural Network Control Algorithm Research of Straight Pull Single Crystal Furnace

In straight pull single crystal furnaces pulling system, Traditional PID controllers parameter cant meet the changes of the DC motor system. In view of this defect that the traditional PID controller parameter can not turn in a timely manner with the DC motor speed change. This paper used a new control method PID neural network to the monocrystalline pulling speed control system and established PID neural network pulling system, at any time to adjust to the optimal PID parameters, to achieve an adaptive control effect and improve the quality of monocrystalline silicon.

Electronic Tension Control of High-Speed and Active Sending Line Based on Fuzzy PID Control

In the case of small diameter( 10000 r/min)winding, high-speed initiative electronic tension control for sending line was designed to solve the problem that the winding motor speed changes at the start and down state and increasing the size of the coil wound level lead to tension fluctuation. The structure, working principle and the factors that affect the tension fluctuation were discussed in detail. The transfer function of this system was deduced, and the Fuzzy PID control algorithm was also introduced to the system. The model of the Fuzzy PID control algorithm and the conventional PID control algorithm were established using MATLAB/SIMULINK tool, The simulation results show that the fuzzy PID control is better than the conventional PID control in improving the dynamic response of the tension controller, furthermore, the control precision and in terms of robustness is showed.

A Novel Seamless Direct Torque Control for Electric Drive Vehicles

Electric drive vehicles (EDV) have received much attention recently because of their environmental and energy benefits. In an EDV, the motor drive system directly influences the performance of the propulsion system. However, the available DC voltage is limited, which limits the maximum speed of the motors. At high speeds, the inverter voltage increases if the square wave (SW) voltage (six-step operation) is used. Although conventional direct torque control (DTC) has several advantages, it cannot work in the six-step mode required in high-speed applications. In this paper, a single-mode seamless DTC for AC motors is proposed. In this scheme, the trajectory of the reference flux changes continuously between circular and hexagonal paths. Therefore, the armature voltage changes smoothly from a high-frequency switching pattern to a square wave pattern without torque discontinuity. In addition, because multi-mode controllers are not used, implementation is more straightforward. Simulation results show the voltage pattern changes smoothly when the motor speed changes, and consequently, torque control without torque discontinuity is possible in the field weakening area even with a six-step voltage pattern.

Modeling longitudinal change in motor and cognitive processing speed in presymptomatic Huntington's disease

Persons who have the genetic mutation responsible for Huntington's disease (HD) have been shown to exhibit lower cognitive test scores years prior to manifest HD. Most studies have examined cognitive performance in presymptomatic persons by using estimated times to manifest HD based on published algorithms. We followed 19 gene-positive persons who were presymptomatic using an objective criterion (i.e., Quantified Neurological Exam score ≤ 10) at baseline for up to 21 years (median = 5 years) with periannual neuropsychological assessments until a diagnosis of manifest HD. Results showed that our tests of information- and psychomotor-processing speed that place minimal demands on cognition, worsening performance became evident 5–10 years prior to the development of manifest HD. In conclusion, cognitive decline precedes motor signs in HD and may be an important target in clinical trials and early intervention. Cognitive test scores may also improve the ability to predict disease onset among gene mutation carriers and help families to better plan for potential personal and economic hardship.

Effect of adjunctive treatment with aripiprazole to atypical antipsychotics on cognitive function in schizophrenia patients

Second-generation antipsychotics yield only a modest improvement in cognitive benefit compared to first-generation antipsychotics. Aripiprazole, which is a partial dopamine D2 receptor agonist, may have an impact on cognitive dysfunction in patients with schizophrenia. This study administered aripiprazole or placebo to 36 outpatients with schizophrenia also receiving risperidone or olanzapine for 12 weeks in a double-blind, randomized, placebo-controlled study. Cognitive function was evaluated using the Brief Assessment of Cognition in Schizophrenia (BACS) just prior to drug administration as well as 12 weeks after. The PANSS and UKU side effect rating scales were used to evaluate the clinical response to additional treatment with aripiprazole. In a primary analyses, ANCOVA showed that there was an interaction between the treatment group and time for verbal fluency (p < 0.05), but not for any domain in BACS, PANSS or UKU side effect rating scales. Upon secondary analysis, however, the ameliorative change in motor speed as assessed by the BACS (p < 0.05) for those receiving aripiprazole was greater than that for the placebo group, whereas deterioration in verbal fluency (p < 0.01) and executive function (p < 0.01) in those receiving aripiprazole was significantly greater than in the placebo group. These results suggest that adjunctive treatment with aripiprazole improves motor speed but worsens some cognitive functions. It is likely that these effects are due to the dopamine D2 antagonistic effect of aripiprazole.

Acute Bouts of Passive Leg Cycling Can Improve Cognitive Function in Parkinson's Patients

Parkinson's disease (PD) often leads to a deficit in cognitive function. Pharmacological therapies are effective in treating motor symptoms in PD, but do not slow the progression of cognitive decline. A number of studies have reported that intensive exercise can improve cognitive function. However, individuals with PD often have difficulties participating in high-intensity exercise. PURPOSE: The purpose of this study is to determine if acute bouts of passive leg cycling can improve cognitive function in PD, and if different rates of pedaling have variable effects on cognitive function. METHODS: Nineteen, mild to moderate idiopathic PD patients (12 men, 7 women, age- 63.2 ± 8.6), reported to the exercise science laboratory on four separate occasions, separated by one week. On the first visit, PD patients completed a YMCA cycling test (Excalibur 1300 W cycle ergometer) to estimate maximal oxygen consumption and a computer based psychomotor tests consisting of Trail Making Test (TMT) A and B while 'on' anti-Parkinson's medication. For the next three visits PD patients participated in passive leg cycling (MOTOmed viva2) at 60, 70 and 80 revolutions per minute (rpm) while 'off' anti-Parkinson's medications. Cycling rates were randomly administered. The TMT A and B were administered prior to and immediately after each cycling session. RESULTS: Data were analyzed using a 3 (trial) by 2 (time) analysis of variance (ANOVA) with repeated measures on both variables. TMT A scores did not differ between trials (p=0.569) or across time (p=0.207). In addition, no trial by time interaction was observed for TMT A Scores (p=0.555). TMT B scores improved across time (70.3 ± 3.7 vs. 62.4 ± 2.6 sec, p=0.003) with no difference between trials (p=0.919) or trial by time interactions observed (p=0.841). The difference in scores between TMT B and A showed a main effect of time (pre: 37.6 ± 2.6, post: 31.0 ± 1.9 sec, p=0.006). CONCLUSION: These data suggest that passive leg cycling can improve executive function in PD patients, as measured by the TMT B. Lack of improvement in the TMT A suggests that TMT B improvement is due to changes in visual search and motor speed alone. However, there is no association between cognitive improvement and passive cycling rate. Future studies will compare these results with active-assisted cycling at variable rates.

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

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

AGE-RELATED CHANGES IN MOTOR SUBTLE SIGNS AMONG GIRLS AND BOYS WITH ADHD

Neuroanatomic structures involved in voluntary control of motor skills show substantial growth, elaboration, and myelination during early childhood.1 Developmental changes in motor control include improvements in speed as well as reduced frequency of “subtle signs,” such as overflow and dysrhythmia. Motor overflow refers to presence of involuntary movements that accompany the production of voluntary movements,2 and has been linked to impaired inhibitory control.3 Dysrhythmia involves improper timing or rhythm during controlled movements. While it is common to observe subtle signs in typically developing children younger than age 10,4 most basic motor skills are mastered by age 6 or 7,5 and persistence of subtle signs into late childhood and adolescence can indicate atypical neurologic development.6,7 The majority of studies examining atypical motor development in attention-deficit hyperactivity disorder (ADHD) have included predominantly male samples, with fewer studies exploring whether similar patterns emerge among girls with ADHD. Studies examining motor skills in typically developing children have shown sex-specific patterns, with girls maturing earlier than boys,8 a finding consistent with trajectories of brain development identified via neuroimaging.9 The purpose of this study was to examine differences in age-related changes in motor speed and subtle signs in boys and girls with and without ADHD. While typically developing children were hypothesized to show improvement with age in motor skills, children with ADHD were hypothesized to show fewer age-related improvements. Further, the inclusion of both boys and girls with ADHD in this study allows us to determine if sex-specific differences observed in brain development are also present within ADHD.

Modeling and Simulation of Single Phase Double Capacitors Induction Motor

The aim of this paper is to study the performances of Single-phase Induction motor at varying Pulse Width Modulation signals (PWM) and adjustable switching capacitance. The control system is implemented in such a way that it allowed the change in motor speed and loading level. The attractiveness of this configuration is the elimination of pulse generating unit, and the centrifugal switch. The pulses are generated based on the back e.m.f, and the duty period of the electronic switches is controlled in such a way with purpose to obtain optimized capacitor values in turn leads to maximum torque and efficiency. The electromagnetic processes are modeled and the simulation results are presented and analyzed in order to obtain optimized solution combining maximum torque with low capacitors values. Matlab/simulink approach is implemented in processing the behaviors of Single Phase Induction Motor, where the most of the machine parameters are accessible for control verification purposes. Prototype model for result verification should be described in future work.

Integrity of cerebral white matter in type 1 diabetes. Reply to Wessels AM [letter

To the Editor: We appreciate the valuable comments of Dr Wessels [1] on our recent article in Diabetologia [2]. We specifically sought to study the impact of white matter hyperintensities (WMHs) on brain structure in relatively young patients (age 32±4 years) with diabetes of long duration (20±4 years) (mean ± SD). As Wessels noted, our large sample of patients did not differ from non-diabetic controls in terms of severity of white matter lesions. Indeed, our results are similar to those of Brands et al. [3], who studied cognition and WMHs in older type 1 diabetic adults with disease of longer duration associated with more complications. Taken together, these studies suggest that the incidence of WMHs in type 1 diabetes is not likely to be high. Using voxel-based morphometry, we have also found that, compared with non-diabetic controls, patients with type 1 diabetes had lower grey matter density and this was associated with both higher HbA1c levels and an increased number of severe hypoglycaemic events [4]. This finding suggests that more sensitive measures of brain structure would reveal changes induced by type 1 diabetes. Wessels notes that type 1 diabetes leads to changes in cognition, which may be mediated by hyperglycaemia, hypoglycaemia and/or vascular disease. The literature on these points is far from conclusive. We observed only small differences in cognition when comparing type 1 diabetic patients to non-diabetic controls [2]. Our results are consistent with a meta-analysis that found modest effects of type 1 diabetes on cognition, characterised by slowing of mental processing and diminished mental flexibility [5]. Furthermore, our cognitive data were consistent with recent results from an 18 year longitudinal study of type 1 diabetic patients enrolled in the Diabetes Control and Complications Trial [6], which found only minimal changes in psychomotor efficiency and motor speed over time among those with the highest HbA1c levels. Wessels’ suggestion that we examine our WMH findings in relation to total white matter volume measurements in patients with and without retinopathy is of interest and would be a useful complementary design. Our goal is to utilise multiple methods of assessing the grey and white matter compartments of the brain, to develop a more precise understanding of the ‘signature’ of type 1 diabetes. Diabetologia (2008) 51:1556–1557 DOI 10.1007/s00125-008-1056-2

Design of low cost universal artificial neuron controller for chopper fed embedded DC drives

Artificial neural network (ANN) has become very popular in many control applications due to their high computation rate and ability to handle nonlinear functions. This paper proposes an artificial neuron controller for closed loop speed control of DC drive fed by DC chopper. Neuron control is used to reduce the steady state error, overshoot and settling time. The signal corresponding to the motor speed error and change in speed error are used as inputs to ANN Controller. The controller outputs the required change in duty cycle of pulse width modulated gating signal applied to DC chopper. Thus the voltage fed to the armature of the DC motor is adjusted for achieving the desired speed response. The training patterns for the neuron controller are obtained from the conventional PI controller and the effectiveness of the proposed neuron controller is studied using simulation studies. The designed controller was implemented in a low cost 8051-based embedded system and the results are documented. Two-loop control system was implemented with an inner ON/OFF current controller and an outer ANN speed controller. A conventional controller has heavy computation burden whereas a trained neural network requires less computation time. The artificial neural network has the ability to generalize and can interpolate in between the training data. This advantage of ANN makes the ANN controller universal. The ANN controller designed was tested on two different motors and found to work effectively on driving both of them.