Dynamical Modeling and Analysis of the Human Jumping Process

2002 ◽  
Author(s):  
A. Meghdari ◽  
M. Aryanpour
Keyword(s):  
Great Influence ◽  
Linear Velocity ◽  
The Body ◽  
Vertical Force ◽  
Dynamical Equations ◽  
Modeling And Analysis ◽  
Hand Motion ◽  
Maximum Value ◽  
Time Histories ◽  
Off Time

A dynamical model was developed in order to study the jumping process in human, and the effect of factors like joint speeds and hand motion. An experiment was designed and setup to compare the theoretical model with the experimental observations. Time histories of vertical force, mass center velocity and driving torques were obtained too. Using dynamical equations, the effect of joint speeds on the maximum values of these quantities is discussed. It is shown that reducing the joint speeds of a body can lead to an unsuccessful jump in which the body does not enter the flight phase. An increase in speed reduces the take-off time (the time necessary for the body to leave the ground) and increases the body’s linear velocity at take-off, as well as, the maximum value of driving torques. Effect of hand motion is also investigated through suppressing motion of the Shoulder and Elbow. It is observed that hand motion has an improving effect on the body’s linear velocity. Although speed of joints did not show to have a great influence on most torques, those at the Shoulder and Elbow were observed to be more sensitive to it.

Characterization of Myoelectric Signals Using System Identification Techniques

2004 ◽  
Author(s):  
Jeffrey T. Bingham ◽  
Marco P. Schoen
Keyword(s):  
System Identification ◽  
Motor Neurons ◽  
Current System ◽  
Electrical Potential ◽  
Computer Software ◽  
The Body ◽  
Myoelectric Signals ◽  
Hand Motion ◽  
The Central Nervous System

Human muscle motion is initiated in the central nervous system where a nervous signal travels through the body and the motor neurons excite the muscles to move. These signals, termed myoelectric signals, can be measured on the surface of the skin as an electrical potential. By analyzing these signals it is possible to determine the muscle actions the signals elicit, and thus can be used in manipulating smart prostheses and teleoperation of machinery. Due to the randomness of myoelectric signals, identification of the signals is not complete, therefore the goal of this project is to complete a study of the characterization of one set of hand motions using current system identification methods. The gripping motion of the hand and the corresponding myoelectric signals are measured and the data captured with a personal computer. Using computer software the captured data are processed and finally subjected to several system identification routines. Using this technique it is possible to construct a mathematical model that correlates the myoelectric signals with the matching hand motion.

scholarly journals THE RELEVANCE OF NUTRITIONAL STATUS AND HISTOPATHOLOGICAL FINDINGS ON THE INFECTIOUS PROCESS OF BALB/C MICE INOCULATED WITH Lacazia loboi

2015 ◽  
Vol 57 (5) ◽  
pp. 421-426 ◽  
Author(s):  
Adriana Sierra Assencio Almeida BARBOSA ◽  
Suzana Madeira DIÓRIO ◽  
Silvia Cristina Barboza PEDRINI ◽  
Adauto José Ferreira NUNES ◽  
Andréa de Faria Fernandes BELONE ◽  
...  
Keyword(s):  
Great Influence ◽  
Giant Cells ◽  
The Body ◽  
Histopathological Analysis ◽  
Restricted Diet ◽  
Regular Diet ◽  
Protein Calorie Malnutrition ◽  
Large Numbers ◽  
Lacazia Loboi ◽  
Lacazia Loboï

SUMMARY The aim of this study was to evaluate the effects of the protein-calorie malnutrition in BALB/c isogenic mice infected with Lacazia loboi, employing nutritional and histopathological parameters. Four groups were composed: G1: inoculated with restricted diet, G2: not inoculated with restricted diet, G3: inoculated with regular diet, G4: not inoculated with regular diet. Once malnutrition had been imposed, the animals were inoculated intradermally in the footpad and after four months, were sacrificed for the excision of the footpad, liver and spleen. The infection did not exert great influence on the body weight of the mice. The weight of the liver and spleen showed reduction in the undernourished groups when compared to the nourished groups. The macroscopic lesions, viability index and total number of fungi found in the footpads of the infected mice were increased in G3 when compared to G1. Regarding the histopathological analysis of the footpad, a global cellularity increase in the composition of the granuloma was observed in G3 when compared to G1, with large numbers of macrophages and multinucleated giant cells, discrete numbers of lymphocytes were present in G3 and an increase was observed in G1. The results suggest that there is considerable interaction between Jorge Lobo's disease and nutrition.

scholarly journals Analisis Kekerasan Permukaan Titanium-6A1-4V Pada Proses EDM Sinking Dengan Aplikasi Response Surdace Methodology (RSM)

2019 ◽  
Vol 9 (02) ◽  
pp. 69-73
Author(s):  
Yuliyanto Yuliyanto
Keyword(s):  
Process Parameters ◽  
Electrical Discharge Machining ◽  
Great Influence ◽  
Coolant Fluid ◽  
Design Expert ◽  
Time Value ◽  
Surface Method ◽  
Alloy Hardness ◽  
Off Time ◽  
Edm Process

This study looked at the effect of severed EDM process parameters on the optimum value of titanium alloy hardness. this study uses Design Expert 9.0 software to help develop an experimental plan of response surface method models and CCD. The machine used is Hitachi Electrical Discharge Machining (EDM) brand with Series H-DS02-S. Material used titanium 6Al-4V. Electrode used copper (Cu). The process parameters used are Current (A), On time (μs) and Off time (μs). Coolant fluid using Hydroseal 63H. The results of data processing there are 20 experiments. This research shows optimum machining condition for hardness (HV) is 322. Analysis of variance (Anova) shows the value of F arithmetic is 3,94, MSE is 0,022 and p (0,0794). The increase of current and on-time values ​​gives a great influence on surface roughness. The increase of Off time value does not give significant effect to the roughness. The next research will be done with 5 (five) process parameters, Current, On time, Off time, Machining Voltage and Servo feed.

Body image(s): Problematizing future physical education teachers’ beliefs about the body and physical activity through visual imagery

2021 ◽  
pp. 1356336X2110562
Author(s):  
Gustavo González-Calvo ◽  
Vanesa Gallego-Lema ◽  
Göran Gerdin ◽  
Daniel Bores-García
Keyword(s):  
Physical Activity ◽  
Body Image ◽  
Physical Education ◽  
Gender Stereotypes ◽  
Great Influence ◽  
The Body ◽  
Physical Education Teachers ◽  
Visual Methods ◽  
Teachers Beliefs ◽  
The World

Visual culture affects the way people understand the world and themselves, contributing to the creation of certain roles and stereotypes, some of which are related to body image. This study focused on interrogating future physical education teachers’ beliefs about the body and physical activity to understand the construction of bodily subjectivities and their perceptions of how these are influenced by visual (physical) culture. Data were collected through the use of visual methods consisting of photo-elicitation and individual interviews with 23 students from a Primary Education Degree with a specialization in physical education at a Spanish university. Data were analyzed using thematic content analysis. The results of the study show that these future physical education teachers are aware of both the great influence of gender stereotypes and the values of consumerism in the field of physical activity stemming largely from the media, which inevitably will shape their future professional practice. However, the results also highlight how these future physical education teachers consider and position the subject of physical education as an important space where they could help students problematize and challenge these beliefs. We suggest that a focus on visual (physical) literacy is needed for future physical education teachers (and their students) to understand the world from a socially critical perspective and transform it in the interest of equity and social justice.

The Forces Exerted on the Substrate by Walking and Stationary Crickets

1980 ◽  
Vol 85 (1) ◽  
pp. 263-279 ◽  
Author(s):  
Jack Harris ◽  
Helen Ghiradella
Keyword(s):  
The Body ◽  
Peak Force ◽  
Vertical Force ◽  
Step Frequency ◽  
Oscillatory Mechanism ◽  
Lower Magnitude ◽  
Stationary Period

1. The gait and the protraction/retraction ratios (P/R ratios) for the cricket are described. They are essentially the same as for the cockroach and the grasshopper. 2. The vertical forces exerted on the substrate by all six legs of walking and stationary crickets are measured. On the basis of the ‘forceprints’ obtained and differences in P/R ratios among the legs of different thoracic segments, it is pointed out that all segments are not functionally identical. Specifically, the greater irregularity of the forceprints of the prothoracic legs, and the lower magnitude of peak force exerted on the substrate by the prothoracic legs suggest that the prothoracic legs are more involved in balancing or searching than in propulsion. 3. The metathoracic legs exert an increased vertical force on the substrate just before the initiation of protraction. This increase correlates with an extension of the leg apparently through extension of the femoraltibial joint. 4. A slight decrease in the force exerted on the substrate by the mesothoracic legs occurs when the leg is at right angles to the body. 5. Placing or lifting one mesothoracic leg does not affect the force exerted by the contralateral mesothoracic leg in a regular way. This argues against mechanical interactions between the legs and in favour of theories invoking central generation of pattern. 6. At a stepping frequency of below 2 steps s−1 the shapes of the forceprints of all legs are no longer repetitive. Also, below 2 steps s−1 there is an increase in the variability of the peak force exerted on the substrate. It is possible that the animal switches to a more sensory sensitive mode below a step frequency of 2s−1. 7. During stationary periods the forces exerted on the substrate continue to show oscillations which may be metachronal. This suggests a mechanism whereby a central oscillatory mechanism can account for the behaviour of an animal starting to walk following such a stationary period.

The Vertical Mean Force and Moment of Submerged Bodies Under Waves

1971 ◽  
Vol 15 (03) ◽  
pp. 231-245 ◽  
Author(s):  
C. M. Lee ◽  
J. N. Newman
Keyword(s):  
Free Surface ◽  
Added Mass ◽  
Cross Sectional Area ◽  
The Body ◽  
Slender Body ◽  
Longitudinal Distribution ◽  
Vertical Force ◽  
Sectional Area ◽  
Cross Sectional ◽  
The Mean

A neutrally buoyant slender body of arbitrary sectional form, submerged beneath a free surface, is free to respond to an incident plane progressive wave system. The fluid is assumed inviscid, incompressible, homogeneous and infinitely deep. The first-order oscillatory motion of the body and the second-order time-average vertical force and pitching moment acting on the body are obtained in terms of Kochin's function. By use of slender-body theory for a deeply submerged body, the final expressions for the mean force and the moment are shown to depend on the longitudinal distribution of sectional area and added mass and on the amplitude and the frequency of the ambient surface waves. The magnitude of the mean force for various simple geometric cylinders is compared with that of a circular cylinder of equal cross-sectional area. The mean force on a nonaxisymmetric body is often approximated by replacing the section with circular profiles of equivalent cross-sectional area. A better scheme of approximation is presented, based on a simple way of estimating the two-dimensional added mass. It is expected that the effect of the cross-sectional geometry on mean vertical force and moment will be more significant when the body is very close to the free surface.

scholarly journals Muscular exercise, lactic acid, and the supply and utilisation of oxygen.—Part XIII. The gaseous exchanges of restricted muscular exercise in man

1926 ◽  
Vol 99 (695) ◽  
pp. 155-166 ◽  
Keyword(s):  
Lactic Acid ◽  
Recovery Process ◽  
The Body ◽  
Muscular Exercise ◽  
Considerable Proportion ◽  
Active Muscle ◽  
A Value ◽  
Maximum Value ◽  
Severe Exercise ◽  
Type Of Exercise

The type of exercise studied in former papers of this series involves the activity of the body as a whole. The characteristic of all such forms of exercise is the free and vigorous movement of nearly all the muscles in the body. Since nearly all the muscles were in activity and behaving in a similar way it was more easy to compare their behaviour with that of an isolated muscle, and in previous papers it has been shown how closely the phenomena of muscular exercise in the body as a whole resemble those accompanying severe exercise in the isolated muscle. As far as concerns the observations described in the succeeding pages, the most pertinent conclusions of the former papers are as follows: (1) Provided that the exercise was not too severe, there occurred what has been called a steady state, in which recovery balanced breakdown in a manner analogous to that shown by Fletcher to occur in isolated frog’s muscle; (2) in severe exercise a considerable proportion of the energy employed is derived, not from contemporary oxidation, but by lactic acid formation on what may be called a “credit” of oxygen secured on the oxidation occurring in the recovery process later; (3) the most severe exercise can be maintained only for about 30 seconds, which corresponds to the time when the lactic acid concentration in the active muscle, as measured by the magnitude of the oxygen debt, may reach a value of about 0·3 per cent., the maximum value found to occur in the isolated frog’s muscle.

Kinematic Mechanics Analysis of Takeoff in Pre-Jumping for Sports Aerobics

2014 ◽  
Vol 1014 ◽  
pp. 157-160 ◽  
Author(s):  
Zi Xin Zhu
Keyword(s):  
Influencing Factors ◽  
Mechanical Model ◽  
Angular Speed ◽  
The Body ◽  
Dynamics Analysis ◽  
Vertical Force ◽  
Bending Angle ◽  
Mechanics Analysis ◽  
Light Pole

Takeoff is important to a variety of difficult movements for sports aerobics. The paper analyzes the kinematic mechanics of takeoff in pre-jumping for the sport. It first discusses the importance of takeoff in sports aerobics, and finds that the mechanics theory can be utilized to analyze the forces produced in the process of takeoff. Then, the dynamics analysis of takeoff in pre-jumping is completed to reveal the change of the vertical force and expound the sports process from the aspect of mechanics. Subsequently, the body for the athlete is simplified a two-light-pole mechanical model. On the basis of this, the mechanics analysis of vertical force in pre-jumping is done to find the influencing factors for vertical force. The results show that the vertical force produced by the takeoff in pre-jumping suffers from the factors of the weight, length of leg, bending angle of knee, and angular speed of leg rotation, etc.

ASSAY OF THYROTROPHIN BY THE ACCUMULATION OF RADIOACTIVE IODINE IN THE THYROID OF THE INTACT RAT

1955 ◽  
Vol 33 (3) ◽  
pp. 248-255 ◽  
Author(s):  
N. R. Stephenson ◽  
W. P. McKinley ◽  
P. J. Kavanagii
Keyword(s):  
Adverse Effect ◽  
Body Weight ◽  
Thyroid Gland ◽  
Radioactive Iodine ◽  
The Body ◽  
Dosage Group ◽  
Maximum Value ◽  
Weanling Rats ◽  
Response Line ◽  
Dose Levels

The ability of the thyroid gland of intact weanling rats to collect injected radioactive iodine was diminished by inclusion of a small amount of iodinated casein in the diet. The administration of exogenous thyrotrophin increased the thyroidal uptake of I131 in rats treated in this manner. Both the degree of inhibition of the thyroid and the ability of the animals to differentiate between dosage levels of thyrotrophin were dependent upon the amount of iodinated casein in the diet. Graded doses of thyrotrophin provided a linear log dose –response line over the range 0.01 to 0.08 U.S.P. units. The response approached a maximum value at dose levels above 0.16 U.S.P. units. The thyroid gland of the female weanling rat retained, on the average, significantly more radioactive iodine than that of the male weanling rat when stimulated by thyrotrophin. Although the hormonal response was not correlated with the body weight of the rats within dosage groups, more precise assays were obtained by equalizing the total weight of the rats in each dosage group before the assay. Relatively large doses of I131 appeared to have an adverse effect on the precision of the assay but did not influence the response to thyrotrophin.

ASSAY OF THYROTROPHIN BY THE ACCUMULATION OF RADIOACTIVE IODINE IN THE THYROID OF THE INTACT RAT

1955 ◽  
Vol 33 (1) ◽  
pp. 248-255
Author(s):  
N. R. Stephenson ◽  
W. P. McKinley ◽  
P. J. Kavanagii
Keyword(s):  
Adverse Effect ◽  
Body Weight ◽  
Thyroid Gland ◽  
Radioactive Iodine ◽  
The Body ◽  
Dosage Group ◽  
Maximum Value ◽  
Weanling Rats ◽  
Response Line ◽  
Dose Levels

The ability of the thyroid gland of intact weanling rats to collect injected radioactive iodine was diminished by inclusion of a small amount of iodinated casein in the diet. The administration of exogenous thyrotrophin increased the thyroidal uptake of I131 in rats treated in this manner. Both the degree of inhibition of the thyroid and the ability of the animals to differentiate between dosage levels of thyrotrophin were dependent upon the amount of iodinated casein in the diet. Graded doses of thyrotrophin provided a linear log dose –response line over the range 0.01 to 0.08 U.S.P. units. The response approached a maximum value at dose levels above 0.16 U.S.P. units. The thyroid gland of the female weanling rat retained, on the average, significantly more radioactive iodine than that of the male weanling rat when stimulated by thyrotrophin. Although the hormonal response was not correlated with the body weight of the rats within dosage groups, more precise assays were obtained by equalizing the total weight of the rats in each dosage group before the assay. Relatively large doses of I131 appeared to have an adverse effect on the precision of the assay but did not influence the response to thyrotrophin.

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