scholarly journals A Mathematical Approach to Modeling Physics for the Vertical Position in Synchronized Swimming

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Devin Johnson ◽  
Benjamin Simonds
Keyword(s):  
Buoyancy Force ◽  
Applied Force ◽  
Upper Body ◽  
Vertical Position ◽  
Total Force ◽  
Surrounding Water ◽  
Straight Line ◽  
Synchronized Swimming ◽  
Buoyancy Forces ◽  
Order Polynomial

In Synchronized Swimming, arguably the most demanding sport known to man, one of the most basic positions is called a vertical. In this position a swimmer’s upper body is submerged in water and their legs are held above the surface while their body is kept in a straight line. Along with the buoyancy forces of the surrounding water and the air in the lungs, swimmers must also support themselves by making movements called sculls with their arms that propel them upwards. This additional force is the applied force. The goal of this research is to use physics principles to create a mathematical model that will help assist synchronized swimmers in maximizing their scores for the vertical position. The math done in this model confirmed that the amount of applied force inversely correlates with the buoyancy force needed to lift the synchronized swimmer out of the water. Additionally, the total force pushing the synchronized swimmer upwards is the same at each level. When the collected data is fitted to a second-order polynomial comparing applied sculling force to desired score, the graph shows that the data had an R2 fit of 0.984. This knowledge could ultimately inform athletes about how to use buoyancy and other forces to their advantage which could increase their performance levels.

scholarly journals The Tangential Force Affecting the Radial Baffles in a Stirred Vessel: Analysis of the Macro-instability Related Component

10.14311/450 ◽  
2003 ◽  
Vol 43 (4) ◽  
Author(s):  
P. Hasal ◽  
I. Fořt ◽  
J. Kratěna
Keyword(s):  
Experimental Data ◽  
Spectral Analysis ◽  
Tangential Force ◽  
Low Frequency ◽  
Frequency Component ◽  
Relative Magnitude ◽  
Tangential Component ◽  
Vertical Position ◽  
Total Force ◽  
Rushton Turbine

Experimental data obtained by measuring the tangential component of the force affecting radial baffles in a flat-bottomed cylindrical mixing vessel stirred with a Rushton turbine impeller is analysed. Spectral analysis of the experimental data demonstrated the presence of its macro-instability (MI) related low-frequency component embedded in the total force. Two distinct dimensionless frequencies (both directly proportional to the impeller speed of rotation N) of the occurence of the MI component were detected: a lower frequency of approximately 0.025N and a higher frequency of about 0.085N. The relative magnitude QMI of the MI-related component of the total tangential force was evaluated by a combination of proper orthogonal decomposition (POD) and spectral analysis. The values of magnitude QMI varied in the interval [rom approximately 0.05 to 0.30. The magnitude QMI takes maximum values at low Reynolds number values (in laminar and transitional regions). In the turbulent region (ReM >20000) the QMI value is low and practically constant. The dependence oj the QMI values on vertical position in the vessel is only marginal. The results suggest that the magnitude of the MI component of the force is significantly influenced by the liquid viscosity and density.

scholarly journals Separate motor memories are formed when controlling different implicitly specified locations on a tool

2019 ◽  
Vol 121 (4) ◽  
pp. 1342-1351 ◽  
Author(s):  
Keaton Proud ◽  
James B. Heald ◽  
James N. Ingram ◽  
Jason P. Gallivan ◽  
Daniel M. Wolpert ◽  
...  
Keyword(s):  
Horizontal Plane ◽  
Applied Force ◽  
Control Points ◽  
Contextual Cues ◽  
Task Context ◽  
Object A ◽  
Task Goal ◽  
Straight Line ◽  
Left And Right ◽  
Straight Ahead

Skillful manipulation requires forming and recalling memories of the dynamics of objects linking applied force to motion. It has been assumed that such memories are associated with entire objects. However, we often control different locations on an object, and these locations may be associated with different dynamics. We have previously demonstrated that multiple memories can be formed when participants are explicitly instructed to control different visual points marked on an object. A key question is whether this novel finding generalizes to more natural situations in which control points are implicitly defined by the task. To answer this question, we used objects with no explicit control points and tasks designed to encourage the use of distinct implicit control points. Participants moved a handle, attached to a robotic interface, to control the position of a rectangular object (“eraser”) in the horizontal plane. Participants were required to move the eraser straight ahead to wipe away a column of dots (“dust”), located to either the left or right. We found that participants adapted to opposing dynamics when linked to the left and right dust locations, even though the movements required for these two contexts were the same. Control conditions showed this learning could not be accounted for by contextual cues or the fact that the task goal required moving in a straight line. These results suggest that people naturally control different locations on manipulated objects depending on the task context and that doing so affords the formation of separate motor memories. NEW & NOTEWORTHY Skilled manipulation requires forming motor memories of object dynamics, which have been assumed to be associated with entire objects. However, we recently demonstrated that people can form multiple memories when explicitly instructed to control different visual points on an object. In this article we show that this novel finding generalizes to more natural situations in which control points are implicitly defined by the task.

Combined Heat and Mass Transfer in Mixed Convection over a Horizontal Flat Plate

1980 ◽  
Vol 102 (3) ◽  
pp. 538-543 ◽  
Author(s):  
T. S. Chen ◽  
F. A. Strobel
Keyword(s):  
Mass Transfer ◽  
Flat Plate ◽  
Heat And Mass Transfer ◽  
Transfer Rate ◽  
Buoyancy Force ◽  
Schmidt Number ◽  
Thermal Buoyancy ◽  
Buoyancy Forces ◽  
Thermal Buoyancy Force ◽  
Species Diffusion

The combined effects of buoyancy forces from thermal and species diffusion on the heat and mass transfer characteristics are analyzed for laminar boundary layer flow over a horizontal flat plate. The analysis is restricted to processes with low concentration levels such that the interfacial velocities due to mass diffusion and the diffusion-thermo/thermo-diffusion effects can be neglected. Numerical results for friction factor, Nusselt number, and Sherwood number are presented for gases having a Prandtl number of 0.7, with Schmidt numbers ranging from 0.6 to 2.0. In general, it is found that, for the thermally assisting flow, the surface heat and mass transfer rates as well as the wall shear stress increase with increasing thermal buoyancy force. These quantities are further enhanced when the buoyancy force from species diffusion assists the thermal buoyancy force, but are reduced when the two buoyancy forces oppose each other. While a higher heat transfer rate is found to be associated with a lower Schmidt number, a higher mass transfer rate occurs at a higher Schmidt number.

Minimax Second-Order Disigns over Hypercubes for the Difference Between Estimated Response at two Points on a Straight Line Through the Origin

1998 ◽  
Vol 48 (1-2) ◽  
pp. 101-108 ◽  
Author(s):  
S. Huda
Keyword(s):  
Design Criterion ◽  
Second Order ◽  
Optimal Designs ◽  
Straight Line ◽  
Order Polynomial ◽  
Polynomial Models ◽  
The Difference ◽  
Experimental Region

Minimization of the variance of the difference between estimated responses at two points on a straight line through the origin maximized over all pairs of such points in the experimental region is taken as the design criterion. Optimal designs are obtained for second-order polynomial models over hypercubes. The performance of best designs within some commonly used classes of designs is also investigated.

Distortion of submerged dog lung lobes

1985 ◽  
Vol 59 (2) ◽  
pp. 521-527 ◽  
Author(s):  
L. E. Olson ◽  
T. A. Wilson ◽  
J. R. Rodarte
Keyword(s):  
Buoyancy Force ◽  
Transpulmonary Pressure ◽  
Vertical Position ◽  
Pressure Curve ◽  
Engineering Analysis ◽  
Vertical Strain ◽  
Analytical Results ◽  
Volume Curve ◽  
Pressure Volume Curve ◽  
Lung Lobes

The conically shaped caudal lobes of dog lungs were submerged, tip downward in saline, and the lateral surfaces of the lobes were thereby exposed to a hydrostatic gradient in transpulmonary pressure. The force that was required to balance the buoyancy was applied through a clip attached to the tip of the lobe. The locations of metal markers implanted in the parenchyma and attached to the surface were tracked, and regional volume and the horizontal and vertical components of strain were obtained as functions of vertical position. An engineering analysis of the deformation is qualitatively consistent with the data, but the predicted strains are larger than the observed strains. From the experimental and analytical results, we conclude that, for this deformation, the regional volume-local transpulmonary pressure curve closely follows the pressure-volume curve because negative horizontal strains nearly balance the positive vertical strain caused by the buoyancy force.

scholarly journals Veterinary student competence in equine lameness recognition and assessment: a mixed methods study

2017 ◽  
Vol 181 (7) ◽  
pp. 168-168 ◽  
Author(s):  
Sandra D Starke ◽  
Stephen A May
Keyword(s):  
Body Movement ◽  
Upper Body ◽  
Self Assessment ◽  
Clinical Rotations ◽  
Perceptual Skills ◽  
Straight Line ◽  
Veterinary Student ◽  
Assessment Skills ◽  
Two Stages ◽  
Structured Questionnaire

The development of perceptual skills is an important aspect of veterinary education. The authors investigated veterinary student competency in lameness evaluation at two stages, before (third year) and during (fourth/fifth year) clinical rotations. Students evaluated horses in videos, where horses were presented during trot on a straight line and in circles. Eye-tracking data were recorded during assessment on the straight line to follow student gaze. On completing the task, students filled in a structured questionnaire. Results showed that the experienced students outperformed inexperienced students, although even experienced students may classify one in four horses incorrectly. Mistakes largely arose from classifying an incorrect limb as lame. The correct detection of sound horses was at chance level. While the experienced student cohort primarily looked at upper body movement (head and sacrum) during lameness assessment, the inexperienced cohort focused on limb movement. Student self-assessment of performance was realistic, and task difficulty was most commonly rated between 3 and 4 out of 5. The inexperienced students named a considerably greater number of visual lameness features than the experienced students. Future dedicated training based on the findings presented here may help students to develop more reliable lameness assessment skills.

CENTER OF MASS-BASED ADMITTANCE CONTROL FOR MULTI-LEGGED ROBOT WALKING ON THE BOTTOM OF OCEAN

2015 ◽  
Vol 74 (9) ◽  
Author(s):  
Addie Irawan ◽  
Md. Moktadir Alam ◽  
Yee Yin Tan ◽  
Mohd Rizal Arshad
Keyword(s):  
Buoyancy Force ◽  
Center Of Mass ◽  
The Body ◽  
Total Force ◽  
Vertical Force ◽  
Hexapod Robot ◽  
Admittance Control ◽  
Foot Placement ◽  
Robot Locomotion ◽  
Foot Motion

This paper presents a proposed adaptive admittance control that is derived based on Center of Mass (CoM) of the hexapod robot designed for walking on the bottom of water or seabed. The study has been carried out by modeling the buoyancy force following the restoration force to achieve the drowning level according to the Archimedes’ principle. The restoration force needs to be positive in order to ensure robot locomotion is not affected by buoyancy factor. As a solution to regulate this force, admittance control has been derived based on the total force of foot placement to determine CoM of the robot while walking. This admittance control is designed according to a model of a real-time based 4-degree of freedom (DoF) leg configuration of a hexapod robot that able to perform hexapod-to-quadruped transformation. The analysis focuses on the robot walking in both configuration modes; hexapod and quadruped; with both tripod and traverse-trot walking pattern respectively. The verification is done on the vertical foot motion of the leg and the body mass coordination movement for each walking simulation. The results show that the proposed admittance control is able to regulate the force restoration factor by making vertical force on each foot sufficiently large (sufficient foot placement) compared to the buoyancy force of the ocean, thus performing stable locomotion for both hexapod and quadruped mode.

Displacer-Type Liquid Level Sensor with Liquid Density Auto-Compensation

2020 ◽  
Vol 15 (3) ◽  
pp. 1-5
Author(s):  
Matheus Oliveira Souza ◽  
Elyson Carvalho ◽  
Jânio Canuto ◽  
Raimundo Freire ◽  
Valner Brusamarello
Keyword(s):  
Buoyancy Force ◽  
Low Cost ◽  
Measuring Method ◽  
Industrial Applications ◽  
Liquid Level ◽  
Liquid Density ◽  
High Linearity ◽  
Buoyancy Forces ◽  
Level Sensor ◽  
Liquid Level Sensor

In the classic displacer-type liquid level measuring method, liquid level is calculated via the buoyancy force exerted by the liquid on a displacer. This technology has high linearity, precision, accuracy, ease of installation and low cost. Nonetheless, displacer level sensors have significant sensitivity to variations in liquid density, which hinder its use in industrial applications that such quantity is not held constant. In this paper a novel displacer-type liquid level sensor is presented and analyzed. The method consists of adding another displacer and thus calculating the new measured value by the quotient of the buoyancy forces of both displacers. Therefore, the new measurement is ideally insensitive to the variations in liquid density. A prototype was built and prototype results presented high linearity, being able to mitigate the sensitivity to the liquid density, increasing accuracy in the measurements.

Combined Free and Forced Convection in Vertical Tubes with Radial Internal Fins

1981 ◽  
Vol 103 (3) ◽  
pp. 566-572 ◽  
Author(s):  
C. Prakash ◽  
S. V. Patankar
Keyword(s):  
Heat Transfer ◽  
Buoyancy Force ◽  
Finned Tube ◽  
Governing Equations ◽  
Finite Difference Technique ◽  
Flow And Heat Transfer ◽  
Buoyancy Forces ◽  
Free And Forced Convection ◽  
Internal Fins ◽  
Vertical Tubes

An analysis is made of the fully developed laminar flow and heat transfer in vertical tubes with radial internal fins to determine the influence of the buoyancy forces. The governing equations for velocity and temperature are solved by a finite difference technique which incorporates a special scheme for treating the two coupled variables. Results are presented for a range of the Rayleigh number and for various values of the fin height and the number of fins. The buoyancy force is found to increase significantly both friction and heat transfer in the finned tube; augmentation factors in the range of 5 to 10 are encountered. The effect of buoyancy is particularly strong when the number of fins is small and the fins are short.

scholarly journals Position of arm and forearm, and elbow flexion during performance of the sculling technique: Technical recommendation versus actual performance

2014 ◽  
Vol 20 (1) ◽  
pp. 33-41 ◽  
Author(s):  
Lara Elena Gomes ◽  
Mônica de Oliveira Melo ◽  
Victor Wigner Tremea ◽  
Marcelo La Torre ◽  
Yumie Okuyama da Silva ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Elbow Flexion ◽  
Flexion Angle ◽  
Vertical Position ◽  
Actual Performance ◽  
Motion Data ◽  
Video Images ◽  
Synchronized Swimming ◽  
Swimming Technique ◽  
Technical Recommendation

Sculling motion is a swimming technique executed in a vertical position with the head above the water's surface and, based on the technical recommendation, should be performed maintaining an elbow flexion angle of 90°, arms kept stationary while the forearms move. In order to verify if this recommendation is indeed realistic, the aim of this study was to describe the elbow flexion angle ant its angular velocity, linear speed and range of motion of the shoulder, elbow and wrist during the sculling motion. Data were calculated using three-dimensional kinematic process from underwater video images of ten athletes of synchronized swimming. The results indicate that the arm is relatively stationary and the forearm moves, which agrees with the technical recommendation. However, the elbow flexes and extends, which contradicts the technical recommendation. These findings should be considered when this action is practiced, especially in synchronized swimming, in which sculling motion is a fundamental technique.

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