Symmetrical Swing Research Articles

Feasibility of Pilates for Late-Stage Frail Older Adults to Minimize Falls and Enhance Cognitive Functions

Globally, we are facing the tendency of aging, and demands for health enhancement among the older population have been steadily increasing. Among various exercise interventions, Pilates has been popularly utilized in rehabilitation; therefore, it is considered suitable for vulnerable populations. In this study, frail late-stage older adults (>75 years) participated in a modified Pilates program (30 min per session, once a week for eight weeks). Age- and condition-matched Controls were also involved as the benchmark to reveal the effect of Pilates. While only the Pilates group participated in the exercise intervention, both groups undertook the health assessments twice (before and after the intervention period). Assessments included: (i) falling risk based on 3D motion capture systems and (ii) overall cognitive functions utilizing Mini-Mental State Examination and executive function with the use of Trail Making Test-A (TMT-A). Two-dimensional mood state was also used to measure changes in mood due to Pilates intervention. An 8-week Pilates intervention was effective in achieving higher and symmetrical swing foot control. Dynamic balance at heel contact was also improved by extending the spatial margin in case of slipping. Despite the trend of positive Pilates effects on executive functions (29% improvement) confirmed by TMT-A, no significant effects were observed for cognitive functions. Positive mood changes were achieved by Pilates intervention, which may be the key for late-stage seniors to continue their participation in exercise programs. While further studies with a larger sample size are essential, Pilates appears to provide adequate exercise for the frail late-stage older population to minimize frailty.

Design and optimization of a lightweight and compact waist mechanism for a robotic rat

A multi-degree-of-freedom (multi-DOF) waist mechanism is required for robotic rats to perform species-typical behaviors, but the existing waist mechanisms are heavy and cumbersome. To solve this problem, we propose a linkage-based slider-coupled symmetric swing (S3) mechanism, which features a single-input multiple-output structure, allowing it to couple multiple DOFs. The linkage mechanism has a variety of forms and linkage curves, making the S3 mechanism suitable for multiple-constraint optimization. Based on kinematic and dynamic analyses, we constrain the S3 mechanism in terms of bending angle, transmission angle, symmetry, and its existence, and then we optimize its dimensions using an interior-point method to make it compact. Compared with an existing waist mechanism, the proposed waist mechanism has only 47.8% of the weight and smaller dimensions, making it more lightweight and compact. Experiments on a robotic rat show that the proposed waist mechanism enables a robotic rat to perform rat-like upright rearing in 0.5s and tail grooming behavior in 0.4s, indicating its good biomimetic and dynamic performances. Comparisons between two generation robotic rats also reveal that the robot with new waist mechanism has similar (sometimes superior) pitching and bending abilities with the former one.

A Novel Method to Directly Analyze Dissolved Acetic Acid in Transformer Oil without Extraction Using Raman Spectroscopy

Analyzing the concentration of low molecular acids dissolved in oil is vital in the oil-paper insulation aging diagnostic procedure of power transformers. The existing methods cannot distinguish between different acid types and their strengths. In this study, an improved solution Raman detection platform is fabricated. The direct measurement of dissolved acetic acid, a kind of low molecular acids, is observed in transformer oil without extraction. The Raman shift line of oil-dissolved acetic acid at 891 cm−1 corresponding to H–C–H symmetrical swing and O–H swing modes is taken as its characteristic value. Taking Raman shift line of pure oil at 932 cm−1 as an internal standard, a linear regression curve for quantitative analysis is obtained with a slope of 0.19. The best platform parameter of accumulation number is 300, which is determined by Allan deviation analysis. The current concentration detection limit and accuracy for oil-dissolved acetic acid are obtained at about 0.68 mg/mL and 91.66%, separately. The results show that Raman spectroscopy could be a useful alternative method for evaluation insulation aging state of an operating power transformer in the future.

Propulsive Characteristics of Twin Oscillating Airfoils

The bionic propulsion can be used on the aerostat and other automatic vehicles. The general single oscillating tail fin can induce the yawing and whole airship rolling because of the lateral force and the gravity moment of heavier oscillating tail fin. The parallel twin oscillating tail fins by symmetrical swing mode can eliminate the lateral force and gravity moment through the symmetrical swing of the two tail fins. The propulsive characteristics of parallel twin fins have not been investigated up to now. In this paper, we investigated the propulsive characteristics and mechanism of parallel twin oscillating airfoils using consistent and symmetrical swing mode. By using the numerical calculation and analysis, the consistent swing mode may decrease the total propulsion efficiency. While, the symmetrical swing mode can improve the propulsion efficiency and reduce the lateral force and gravity moment. This mode can be used to propel the aerostat and automatic underwater vehicles efficiently.

A Swing Arc System for Narrow Gap GMA Welding

A novel swing arc system was developed to realize high quality narrow gap GMA welding at low cost. This system uses a motor of hollow axis to turn directly the micro-bent conductive rod and then to weave circularly the arc around itself axis of torch, and can automatically search for the midpoint of symmetrical swing trail and detect precisely swing frequency in real time. Three mathematical models are also presented to calculate precisely key swing variables from torch structure and process parameters. Experimental results show that weld surface curvature and the penetration into groove sidewalls increase and weld sectional thickness decreases with increasing swing frequency and at-sidewall staying time of arc, while bottom shape of bead varies from single to twin peaks. This swing arc process thus improved obviously narrow gap weld formation.

Graphical techniques for the study of biasing in common-emitter amplifiers

Abstract The role of symmetrical swing and voltage gain specifications in the design of a common-emitter amplifier stage which is required to have acceptable performance over a given temperature range is considered. It is shown that a hierarchical approach, wherein the original problem is converted into one of coordinating the solutions to a set of appropriately structured subproblems, leads to a set of graphical representations which are quite useful in depicting the constraints of this design problem. A design procedure and some interesting bounds on the attainable specifications arc developed from these results and are illustrated via two design examples.