Backward Movement Research Articles

Design and Experiment of a Clamping-Drive Alternating Operation Piezoelectric Actuator

In recent years, piezoelectric actuators, represented by inertial and inchworm actuators, have been widely applied because of their high accuracy and excellent responsiveness. Despite the development of various piezoelectric actuators, there remain some flaws in this technology. The sticking point is that the piezoelectric actuators based on the friction driving principle are prone to unwanted backward motion when outputting stepping motion. It is thus urgent to explore solutions from the perspectives of principle and structure. In this paper, a clamping-drive alternating operation piezoelectric actuator is proposed, the two feet of which are driven by two piezoelectric stacks, respectively. Due to double-foot alternate drive guide movement, backward movement is prevented in theory. By adopting the double-layer stator structure, integrated processing and assembly are facilitated. Meanwhile, a double flexible hinge mechanism is installed in the stator to prevent the drive foot from being overturned due to ineffectiveness and premature wear. In addition, the stator is equipped with the corresponding preload mechanism and clamping device. After the cycle action mechanism of one cycle and four steps is expounded, a model is established in this study to further demonstrate the principle. With the prototype produced, a series of experiments are performed. In addition, the amplitude of actuation of the stator is tested through amplitude experiment. The performance of the stator is evaluated by conducting experiments in the alternating step and single step actuation modes. Finally, the test results are analyzed to conclude that the actuator operating in either of these two modes can meet the practical needs of macro and micro actuation.

Dynamic Response Difference of Hydraulic Support under Mechanical-Hydraulic Co-Simulation: Induced by Different Roof Rotation Position and Hysteresis Effect of Relief Valve

As key supporting equipment in coal mining, hydraulic supports are vulnerable to impact pressure from roof movement and deformation. In this paper, a mechanical-hydraulic co-simulation platform for hydraulic supports is established. Moreover, the rationality of the simulation platform is verified. Based on this platform, the rigid-flexible coupling impact dynamics model of hydraulic support is built. Finally, by delaying the opening time of the relief valve, the energy dissipation problem of the relief valve hysteresis effect on the hydraulic support system under the rotary impact is discussed. The results indicate that the rotary load acting on the hydraulic support decreases gradually with the backward movement of the roof rotary position, which causes the peak pressure in the column to decrease (by 69 MPa). The hinge point load of different parts shows different load transfer laws. The hysteresis effect of the relief valve prolongs the energy release time of the system, increasing the pressure in the column by 23 MPa. The instantaneous opening speed of the relief valve spool reaches 15.7 m/s, and the hinge point between the top beam and the column is most sensitive to the hysteresis effect (impact coefficient increases by 0.63).

The Effect of Intrathecal Bupivacaine Plus Dextrose 5% and Fentanyl Compared with Bupivacaine Alone on the Onset and Duration of Analgesia in Patients Undergoing Lower-Limb Orthopedic Surgery.

This study aimed to compare the effect of intrathecal bupivacaine plus dextrose 5% and fentanyl with bupivacaine alone on the onset and duration of analgesia in patients undergoing lower-limb orthopedic surgery. A total of 40 patients eligible for lower-limb surgery were divided into two groups by simple randomization: the control group which received only bupivacaine and the intervention group which received bupivacaine plus dextrose 5% and fentanyl. Anesthesia was induced by the spinal method. The visual analog scale (VAS) was used to assess the patients' pain; hemodynamic status (systolic and diastolic blood pressure and the heart rate) and oxygen saturation were also monitored. There was a significant difference between groups in the type of lower-limb movement at the L1 anesthesia level, the sensory block level at time zero after surgery, the type of backward movement at time zero after surgery, and the analgesic dose received (p < 0.05). Fifteen and 30 minutes after the start of surgery, mean systolic blood pressure, and 45 and 60 minutes after the start of surgery, systolic and diastolic blood pressure and the heart rate were significantly lower in the control group than in the intervention group (p < 0.05). The VAS score was significantly lower in the intervention group than in the control group at 6 and 24 hours after surgery (p < 0.05). Systolic and diastolic blood pressure at time zero, systolic blood pressure at hour 6, and diastolic blood pressure at hour 24 after surgery were significantly lower in the control group than in the intervention group (p < 0.05). The mean duration of anesthesia and analgesia was significantly longer in patients receiving bupivacaine plus fentanyl than in those receiving bupivacaine alone. However, concerning hemodynamic parameters, it cannot be concluded that the bupivacaine plus fentanyl receiving group was generally superior to the bupivacaine receiving group.

Temporal organization in narratives texts of 8-11-years-olds

The present work focuses on the temporal organization of narratives written by pupils aged 8-11. In this paper, we analyze 180 texts produced by elementary school children (60 texts from pupils aged 8-9, 60 texts from pupils aged 9-10, 60 texts from pupils aged 10-11) in response to a common writing instruction prompt in which the beginning and end of the text are given. The different temporal movements (chronological succession, backward and forward movements) are cataloged, categorized, and analyzed. The study reveals, on the one hand, that all pupils, regardless of their grade level, integrate temporal movements in their texts. On the other hand, it shows that differences appear according to class level: as class level increases the different movements tend to develop with their own specificity conveying more thickness and coherence to the text.

Hand Gesture Design Using Bionic Prosthetic Hand

Brain computer interface (BCI) system empowers command over external device by retrieving brain waves and interpreting them into machine instructions. The system utilizes electroencephalogram (EEG) for receiving, processing and classifying signals to control by means of brain generated signals. The paper focuses on mental task design for BCI by acquiring the signals generated by mental activity through EEG comb electrodes, placed over three-dimensional (3D) printed headset. The experiment involved the blinking of left and right eye for the forward and backward movements of the prototype wheelchair. The experimental measurement was performed using a Cyton board where the information was transmitted through Bluetooth which were later processed and translated to the wheelchair to perform activities. The system has successfully achieved the real time control of an assistive device by using signals from the brain.

Mental Task Design Based on EEG Signal for Brain Computer Interface System

Abstract: Brain computer interface (BCI) system empowers command over external device by retrieving brain waves and interpreting them into machine instructions. The system utilizes electroencephalogram (EEG) for receiving, processing and classifying signals to control by means of brain generated signals. The paper focused on mental task designs for BCI by acquiring the signals generated by mental activity using EEG comb electrodes, placed over three-dimensional (3D) printed headset. The experiment involved the blinking of left and right eyes for the forward and backward movements of the prototype wheelchair. The experimental measurement was performed using a Cyton board where the information was transmitted through Bluetooth which were later processed and translated to the wheelchair to perform activities. The system has successfully achieved the real time control of an assistive device by using signals from the brain.

The Triple Aim Quality Improvement Gold Standard Illustrated as Extremely Premature Infant Care.

The Triple Aim is widely regarded as the quality improvement gold standard that enhances population health, lowers costs, and betters individual care. There have been no large-scale, sustained demonstrations of such improvement in healthcare. Illustrating the Triple Aim using relevant extremely premature infant outcomes might highlight interwoven proficiency and efficiency complexities that impede sustained value progress. Ten long-term collaborating neonatal intensive care units (NICU) in the Vermont Oxford Network calculated the Triple Aim in 230/7 to 276/7-week infants using three surrogate measures: (1) population health/x-axis-eight major morbidity rates as a composite, risk-adjusted metric; (2) cost/y-axis-total hospital length of stay; and (3) individual care/z-axis-mortality, then illustrated this relationship as a sphere within a three-dimensional cube. Three thousand seven hundred six infants born between January 1, 2014 and December 31, 2019, with mean (standard deviation) gestational age of 25.7 (1.4) weeks and birth weight of 803 (208) grams were analyzed. Triple Aim three-axis cube positions varied inconsistently comparing NICUs. Each NICUs' sphere illustrated mixed x- and z-axis movement (clinical proficiency), and y-axis movement (cost efficiency). No NICU demonstrated the theoretically ideal Triple Aim improvement in all three axes. Backward movement in at least one axis occurred in eight NICUs. The whole-group Triple Aim sphere moved forward along the x-axis (better morbidities metric), but moved backward in the y-axis length of stay and z-axis mortality measurements. Illustrating the Triple Aim gold standard as extreme prematurity outcomes reveals complexities inherent to simultaneous attempts at improving interwoven quality and cost outcomes. Lack of progress using relevant Triple Aim parameters from our well-established collaboration highlights the difficulties prioritizing competing outcomes, variable potentially-better-practice applications amongst NICUs, unmeasured biologic interactions, and obscured cultural-environmental contexts that all likely affect care. Triple Aim excellence, if even remotely possible, will necessitate scalable, evidence-based methodologies, pragmatism regarding inevitable trade-offs, and wise constrained-resource decisions. · The Triple Aim gold standard is elusive. There is no demonstration of sustained, large-scale success in healthcare and our quality improvement network has previously published benchmark extreme prematuritymorbidity improvements.. · Extreme prematurity outcomes illustrated as the Triple Aim show uneven results in relevant surrogate parameters and Triple Aim achievement, if even possible, will necessitate evidence-based methodologies that are scalable.. · Pragmatism, inevitable trade-offs, and wise constrained-resource decisions are required for Triple Aim success..

3D printing-assisted and magnetically-actuated superhydrophobic surfaces for droplet control

This paper presents a novel fabrication method for magnetically controllable micro-patterned wall arrays (MCMAs) for manipulating droplets. The MCMA films exhibited superhydrophobic properties (contact angle of 153.7°) without additional post-treatment using the microstructure of the surface, which is a characteristic of fused-filament-fabrication-type additive manufacturing. To operate the MCMA films, the bending characteristics due to the magnetic force were analyzed, and the droplet transport pattern was verified under various conditions (e.g., structure height and droplet size). The droplet was rapidly manipulated on the MCMA films by using a magnet moved at a speed of 7.5 mm/s. The droplet showed a three-step transport pattern of backward movement, forward movement, and detachment depending on the relative position between the droplet and the magnet. A film composed of MCMAs with a high aspect ratio produced a continuous concave surface shape when driven by a magnetic force. The concave surfaces played an important role in the stable transport of droplets. MCMA films are expected to be applied in various scientific and industrial fields where droplet transport, mixing, and collection are used with careful droplet controlling is needed.

Mechanism Affecting the Performance and Stability of a Centrifugal Impeller by Changing Bleeding Positions of Self-Recirculating Casing Treatment

This study aimed to investigate the influence of the bleeding position of a self-circulating casing on the aerodynamic performance of a transonic centrifugal compressor. Three types of self-circulating structures with the bleeding positions of 11% Ca (the axial chord length of the blade tip), 14% Ca and 20% Ca from the leading edge of the blade were studied by using the numerical simulation method, with the Krain impeller taken as the research object. It was found that all three types of self-recirculating casing treatments can expand the stable operating range of the impeller, and that at medium and small flow rates, the total pressure ratio and efficiency of the impeller increase gradually with the backward movement of the bleeding position. The self-circulating casing treatment can restrain the development of tip leakage vortex, reduce the blockage area, and improve the stability of the impeller by sucking low-energy fluid. The farther back the bleeding position is, the greater the bleeding mass flow rate of the self-circulating casing for the low-energy fluid in the blade-tip passage becomes. Additionally, a greater inhibition effect on the tip leakage vortex, and a better effect of improving the performance and stability of the impeller, can be obtained. The best air bleeding position is 20% Ca, but it is not directly above the blade-tip blockage center of the solid wall casing passage. Instead, it is downstream of the blockage area.

Comparison of Various Smoothness Metrics for Upper Limb Movements in Middle-Aged Healthy Subjects.

Metrics for movement smoothness include the number of zero-crossings on the acceleration profile (N0C), the log dimensionless jerk (LDLJ), the normalized averaged rectified jerk (NARJ) and the spectral arc length (SPARC). Sensitivity to the handedness and movement type of these four metrics was compared and correlations with other kinematic parameters were explored in healthy subjects. Thirty-two healthy participants underwent 3D upper limb motion analysis during two sets of pointing movements on each side. They performed forward- and backward-pointing movements at a self-selected speed to a target located ahead at shoulder height and at 90% arm length, with and without a three-second pause between forward and backward movements. Kinematics were collected, and smoothness metrics were computed. LDLJ, NARJ and N0C found backward movements to be smoother, while SPARC found the opposite. Inter- and intra-subject coefficients of variation were lowest for SPARC. LDLJ, NARJ and N0C were correlated with each other and with movement time, unlike SPARC. There are major differences between smoothness metrics measured in the temporal domain (N0C, LDLJ, NARJ), which depend on movement time, and those measured in the frequency domain, the SPARC, which gave results opposite to the other metrics when comparing backward and forward movements.

Finding Effective Adjustment Levels for Upper Limb Exergames: Focus Group Study With Children With Physical Disabilities

We developed the Blexer system consisting of a database and a web interface for therapists that can host different types of adaptive and personally configurable virtual reality exergames based on Kinect (Microsoft Corp) motion capture to provide entertaining exercises for children with motor disabilities. It allows for parameter adjustment and the monitoring of results remotely, thereby providing a useful tool to complement traditional physical therapy sessions with home exercises. The aim of this study was to observe the motor benefits achieved through the use of a video exergame and the importance and implications of correctly setting the game's difficulty parameters. This was an observational case study of 6 children with different physical disabilities receiving physical therapy at school combined with the use of a fully configurable exergame under research that forms a part of the Blexer environment. The game integrates 4 repeatedly appearing upper limb exercises with individually adjustable difficulties (intermittent arm rising, arm forward and backward movement, rising and holding of one arm, and trunk control in all directions). The outcomes were 3 assessments of 2 efficacy measures: Box and Block Test and Jebsen Taylor Hand Function Test. A total of 5 children with cerebral palsy (mean 8.4, SD 2.7 years; Gross Motor Function Classification II-2/5, 40%; III-2/5, 40%; and IV-1/5, 20%) and 1 child with obstetric brachial plexus palsy (aged 8 years; Mallet Classification III) received between 8 and 11 sessions of training (10-20 minutes per session), depending on age, motivation, and fatigue. Significant associations were observed between game parameter settings and improvements in motor function, on the one hand, and between the type of improvement and disability severity, on the other: with adjusted game parameters goal and time in the range of 70% to 100%, only less affected children improved in the Box and Block Test (+11 blocks vs -1 block), and more affected children improved more in the Jebsen Taylor Hand Function Test (+90 seconds vs +27 seconds). When defining the difficulty parameters for an exergame, we suggest a classification in levels ranging from very easy to very hard. For practical use, we suggest setting the difficulty for the player to an easy or medium level rather than high-commitment goals, as this leads to a longer playtime with more fun and, therefore, seems to improve the results of the game and, consequently, mobility.

Bow Hunter's syndrome with clicking sounds: A rare etiology of transient loss of consciousness with tonic-clonic seizure.

We present the case of a young male patient experiencing a transient loss of consciousness and manifesting a seizure when he tilted his head backward. Transcranial Doppler ultrasound (TCD) and carotid artery ultrasound (CAU) examination were normal when the patient's neck was in the neutral position. However, the CAU revealed vertebral artery (VA) transient occlusion during neck rotation or backward movement. Electroencephalogram (EEG) monitoring was performed with multiple neck rotation-induced tests. The patient developed dizziness, which was the same as the prodromal symptoms of the first seizure, and the EEG showed a large number of spinal slow waves and sharp slow waves in the frontal-to-frontal midline area, with an occasional generalization trend. CT angiography revealed occipitalization of the atlas and the lack of contrast agent filling in the local area of the VA when the patient's head was turned contralaterally. Thus, the patient was diagnosed with Bow Hunter's syndrome (BHS) and treated conservatively with neck immobilization. No recurrence occurred at 3 and 6 months of follow-up. Therefore, this case alerts neurologists to suspect BHS on observing seizure manifestations during neck rotation, and CAU may be a recommended dynamic screening method for BHS. This report is accompanied by a discussion of the phenomenon and diagnosis in the context of the existing literature.

Study on Collision Process of Opposing Unsteady Supersonic Jets and Shock Waves

Double pulsed-laser-ablation is a promising method to prepare nanoparticle composites. The backward movement of the plume after the collision with counter-propagating shock wave has been observed in experiments. In the present study, collision dynamics of the oppositely injected Si and Ge jets into a He background gas was numerically calculated as a simulation for double pulsed-laser-ablation. The experimentally observed backward movement was reproduced. The effect of distance between two jet exits on the distance of backward movement of the jet, BL, after the collision with the counter-propagating shock front was calculated to discuss the collision dynamics and to optimize the target distance for the experiment. We found that BL does not decrease monotonically with increasing distance between two jet exits, but has a maximum value at a certain distance. This behavior is discussed by calculating the expansion dynamics of an individual jet. Shock wave grows with time at the initial stage of the jet expansion and then attenuates; the density just behind the shock front for individual jet has a maximum value at a certain time and position. BL has a maximum value when the densities just behind the shock fronts for the individual jets have maximum values. This result is important for designing the appropriate distance between the two jet exits, i.e., the distance between the targets of double pulsed-laser-ablation.

PH-Responsive swimming behavior of light-powered rod-shaped micromotors.

Micromotors have emerged as promising devices for a wide range of applications e.g., microfluidics, lab-on-a-chip devices, active matter, environmental monitoring, etc. The control over the activity of micromotors with the ability to exhibit multimode swimming is one of the most desirable features for many of the applications. Here, we demonstrate a rod-shaped light-driven micromotor whose activity and swimming behavior can easily be controlled. The rod-shaped micromotors are fabricated through the dynamic shadowing growth (DSG) technique, where a 2 μm long arm of titanium dioxide (TiO2) is grown over spherical silica (SiO2) particles (1 μm diameter). Under low-intensity UV light exposure, the micromotors exhibit self-propulsion in an aqueous peroxide medium. When activated, the swimming behavior of micromotors greatly depends on the pH of the medium. The swimming direction, i.e., forward or backward movement, as well as swimming modes like translational or rotational motion, can be controlled by changing the pH values. The observed dynamics has been rationalized using a theoretical model incorporating chemical activity, hydrodynamic flow, and the effect of gravity for a rod-shaped active particle near a planar wall. The pH-dependent translational and rotational dynamics of micromotors provide a versatile platform for achieving controlled and responsive behaviors. Continued research and development in this area hold great promise for advancing micromotors and enabling novel applications in microfluidics, micromachining, environmental sciences, and biomedicine.

DISCOVER THE REAL TRUTH THROUGH POWER OF SPIRITUALITY: CHANGE OF ATMOSPHERE FOR THE NEW WORLD

The present human civilization is moving forward along with many backward motions, generation after generation. At the same time, in the running society amidst a lot of conventional ordinary zero-point or negative works, few giant steps are taken for the good of the people in the long run. Mental capacity of common people is not so powerful to catch the negative vibrations against the deeds taken for granted, today; and, hence, in majority cases, solution does not come. We blame one another and the situations become worse day by day. We always try to rationalize the irrationals by our own judgments, introducing falsehood, mistrust and selfishness; and, hence, in no way the problems reduce. Rather, the whole society is being entangled in a variety of mental turbulences in which we all have been captured directly or indirectly. Actually, we have lost our inner power as a result of forgetting our original spiritual identity. The right knowledge and understanding of soul, Supreme Soul and World Cycle, and self-realization and God-realization made clear the universal concept of One-World -Family in the sense that every human being is the spiritual child of God Father Shiva irrespective of the differences of castes, colours, creeds, cultures, faiths, religions, languages, genders, nationalities, places of birth, etc.

Implementation of the backward movement to an autonomous ATV and experiment of straight passage tracking PGR

Implementation of the backward movement to an autonomous ATV and experiment of straight passage tracking PGR

Evaluation of Treatment Outcomes of Skeletal Class III Malocclusion Resulted from Dynaflex Appliance: A Clinical study

Purpose: This clinical study was carried out to assess skeletal and dentoalveolar changes introduced by Dynaflex appliance on skeletal class III malocclusion treatment. Materials and methods: 8 patients (4 males & 4 females) aged 10-13 years old with skeletal class III discrepancy (-3 < ANB < 0) and dental class III malocclusion were treated using Dynaflex. Following leveling and alignment the appliance was positioned mesial to maxillary first molars and distal to mandibular canines. After reaching normal overbite and overjet with Class I molar and canine relationship, Dynaflex was removed. Lateral cephalometric radiographs were taken before treatment and after Dynaflex removal. Tracing for the two radiographs were done digitally using Webceph software. Skeletal, dental, and soft tissue changes were calculated by subtracting measurements taken before treatment from measurements taken after Dynaflex removal. Results: Positive overjet with class I molar and canine relationship was accomplished. Significant skeletal, dental, and soft tissue changes between pre and post treatment radiographs were detected. Forward movement of maxillary base by 1.9 mm and backward movement of mandibular base by 1.3 mm were seen with ANB improvements. Forward movement of maxillary incisors by 2.1 mm was found. Upper and lower lip showed significant protrusion and retrusion, respectively. Conclusion: Dynaflex appliance can be used to correct mild to moderate skeletal class III malocclusion (-3 < ANB < 0) with minimal patient compliance. Factors that contributed to overjet correction were anterior movement of maxilla, posterior and downward movement of mandible together with maxillary incisors proclination.

Analysis of Coal Transportation Efficiency of Horizontal Screw Conveyor Based on EDEM

In order to analyze the coal conveying capacity of horizontal screw conveyor, the pitch, blade thickness and speed are combined in order, and the EDEM orthogonal test is carried out with the conveying time of a certain number of particles as the test index, and the simulation is carried out to explore the influence of test factors on the test index. The research shows that the larger the pitch, the shorter the time it takes to transport the same batch of materials, and the higher the transportation efficiency. Blade thickness has little effect on material transportation efficiency, and increasing the thickness of spiral blades can increase the strength of blades. In a certain range, the higher the rotating speed, the shorter the time it takes to transport the same batch of materials. However, after the rotating speed is too high, the particles will rebound and hit the wall due to the increase of centrifugal force. When the number of particles decreases gradually, the collision will be more obvious, which will lead to the unstable forward transportation of materials and even the backward movement of materials. Thereby reducing the transportation efficiency. This situation shows that when the speed is too high, its conveying capacity will decrease. The optimal combination is pitch 500mm, blade thickness 6mm and rotating speed 90r/min.

Agency and social affordance shape visual perception

Research on the sense of agency has shown that being the author of an action changes the way we estimate the timing and the intensity of the action-effect. Yet, there is a dearth of attempts to assess the influence of agency on perception per se. The present study used the Representational Momentum paradigm to measure participants' visual anticipation of movement while manipulating their agency. In line with previous literature emphasizing the impact of social factors on visual anticipation and on the sense of agency, we additionally investigated the modulating power of social affordances on the relationship between agency and visual anticipation. We conducted two experiments where participants viewed a virtual agent directing a handshake gesture toward a second virtual agent. In a first experiment, we addressed the role of agency on visual anticipation by comparing a condition in which participants triggered the virtual agent's gesture with a condition where the computer triggered the gesture. Results showed greater forward movement anticipation when participants triggered the gesture. The second experiment investigated how altering social interaction parameters (interindividual distance and body posture) modulated the relationship between agency and visual anticipation. The outcome contrasted with the first experiment, with participants anticipating a backward movement of the hand when the computer triggered the gesture and displaying a null anticipation when participants triggered the gesture. Those two experiments highlighted how active involvement and environmental affordance interact to shape perception and allowed us to propose an updated model of agency processing.

Torsional vibration feature extraction method from lateral vibrations based on decomposed forward and backward whirl motions

The high-speed turbomachinery rotor-bearing system faces potential torsional vibration problems due to its large span, flexible structure, and the wildly use of variable frequency drive systems. In this paper, a method based on the Hilbert technique to extract weak torsional vibration signals from measured lateral vibration signals is proposed, and the forward whirl signal is constructed to make full use of the information contained in lateral vibration signals. Furthermore, it was found that the forward whirl signal has better stability and stronger anti-noise ability after comparing the utilization of horizontal, vertical, forward, and backward vibration signals applied to the proposed method to extract the torsional vibration signal from simulated vibration responses of a rotor system. Numerical simulation and experimental results indicate that the method can detect torsional vibration signals accurately, with a high resolution in frequency estimation. This method enables additional monitoring of torsional vibrations for machines without dedicated torsional vibration testers and provides a convenient way to measure torsional vibrations in engineering applications.