scholarly journals Posudzovanie kvality odrazu pri salte vpred na základe časových charakteristík okamžitých síl na krivkách odrazu vo vertikálnych a horizontálnych rovinách v realizačnej fáze

2010 ◽  
Vol 4 (1) ◽  
pp. 53-58
Author(s):  
Rastislav Feč ◽  
Tibor Klaček
Keyword(s):  
Horizontal Plane ◽  
Test Group ◽  
Time Frame ◽  
Vertical Force ◽  
Spearman Correlation ◽  
Maximum Value ◽  
Potential Indicator ◽  
Coeffi Cients ◽  
Correct Technique ◽  
Correlation Coeffi

The paper deals with looking for potential indicators of correct technique of bounce concerning a tucked forward somersault on the base of relations between time characteristics of instantaneous forces in a vertical and horizontal plane in a realization phase of the bounce. Our test-group was created by 13 students of Faculty of Sport. We used statistical signifi cance of Spearman correlation coeffi cients p ≤ 0,05 as a method for judging whether or not a particular ratio of the impulses of forces in the vertical and horizontal plane represents a suitable indicator of correct technique of bounce. We assumed that some of the observed ratios will represent the potential indicator of correct technique of bounce. Th e hypothesis was confi rmed. Th e potential indicators of bounce are the following: variable 4 (time frame since vertical force reached its maximum value to the end of jump to total time of bounce), variable 6 (time frame since vertical force reached its maximum value to the end of bounce to the time frame from when horizontal force reached its maximum value to the end of bounce), variable 2 (time frame since vertical force reached its maximum value to the end of bounce).

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.

The correlation between dairy productivity traits in the herd of holsteinized cows of Black and White breed

2020 ◽  
pp. 21-27
Author(s):  
N. Fedoseeva ◽  
V. Usov ◽  
D. Shepinyev
Keyword(s):  
Milk Yield ◽  
Mass Fraction ◽  
Milk Productivity ◽  
High Positive Correlation ◽  
Positive Correlation ◽  
Black And White ◽  
Mass Fractions ◽  
White Breed ◽  
Coeffi Cients ◽  
Correlation Coeffi

It is important to study the nature of the association between the characteristics of milk productivity in breeding work with cattle. The purpose of the researches was to study the correlation between the traits of milk productivity in the herd of holsteinized cows of Black-and-White breed. A signifi cant low negative correlation r=–0,108 (P < 0,01) and r=–0,125 (P < 0,001) has been found between the traits of milk yield and the mass fractions of fat and protein for the 1st lactation. It should be noted that for the 1st, 2nd lactations and on average for the fi rst three lactations between the mass fractions of fat and protein a reliable average positive correlation has been determined from r=0,512 (P < 0,001) to r=0,565 (P < 0,001), for the 3rd lactation a high positive correlation has been found r=0,613 (P < 0,001). It has been found for all three lactations that milk yield had high, positive and reliable correlation coeffi cients with milk fat yield from r= +0,958 (P < 0,001) to r=+0,974 (P < 0,001) and milk protein yield from r=+0,995 (P < 0,001) to r=+0,997 (P < 0,001). This can serve as an indicator of possible eff ective selection based on these characteristics. In order to determine the infl uence of sires on the content of mass fractions of fat and protein in the milk of their daughters, the degree of correlation of these characteristics has been studied. Correlation coeffi cients between milk yield and fat mass fraction were negatively low from r=–0,139 (P < 0,01) to r=–0,280 (P < 0,05). The correlation between milk yield and protein mass fraction has been found from the average negative value of r=–0,372(P < 0,05) to the positive low indicator – r=+0,234 (P < 0,001). The correlation coeffi cients have been obtained for milk productivity indicate the individual characteristics of individual sires.

Physical Interpretations of the Instabilities Encountered in the Deflection Equations of the Unconstrained Pipeline

1976 ◽  
Vol 98 (3) ◽  
pp. 1099-1102
Author(s):  
G. C. Daley
Keyword(s):  
Differential Equations ◽  
Parametric Study ◽  
Flexural Rigidity ◽  
Unit Length ◽  
Vertical Force ◽  
Continuous Beam ◽  
Pipeline Construction ◽  
Sea Floor ◽  
Maximum Value

For a pipeline modeled as having constant rigidity, horizontal tension, and submerged weight per unit length, there is a maximum value that the maximum sag-bend moment attains as the distance from the pin-supported end of the pipe to the sea floor increases. This paper presents the results of a parametric study analyzing a pipeline displaced from the sea floor to some pipeline construction configuration. The pipeline is modeled as a continuous beam having constant submerged weight per unit length and a constant horizontal tension or force with one end supported vertically by the sea floor. The governing differential equations are solved in terms of dimensionless combinations of the three characteristic variables—the submerged weight per unit length, the flexural rigidity, and the constant horizontal tension. This allows any possible pipeline configuration meeting stated constraints to be analyzed. The analysis performed specifies the maximum sag-bend moment. This maximum sag-bend moment is changed by varying the sea floor vertical force until a further change in sea floor reaction does not give a pipeline configuration. This maximum attainable maximum sag-bend moment is then computed and graphed as a function of the three characteristic pipeline values, the horizontal tension, the flexural rigidity, and the submerged weight per unit length.

scholarly journals The Method of Generalized Ray-Revisited

2000 ◽  
Vol 16 (2) ◽  
pp. 125-126 ◽  
Author(s):  
Franz Ziegler ◽  
Piotr Borejko
Keyword(s):  
Fourier Transformation ◽  
Horizontal Plane ◽  
Axisymmetric Problem ◽  
Plane Waves ◽  
Three Dimensional ◽  
Dimensional Case ◽  
Vertical Force ◽  
Force Vector ◽  
Coordinate Rotation ◽  
Single Force

In Section 2, ROTATION OF COORDINATES, the Authors derived the emittance functions in the Weyl-Sommerfeld representation of the wave potentials for a horizontal instantaneous single force from those known for a vertical force from conditions of invariance of the phase and amplitude of plane waves under coordinate rotation, Eqs. (10) ∼ (13) and (18) ∼ (20). That transformation implies the validity of the commonly applied identity for the (force) vector components when rotating the vector in the opposite sense to the coordinate rotation. Further, in the three-dimensional case, the vertical force poses an axisymmetric problem which is compatible with the Fourier transformation applied to the coordinates in the horizontal plane.

scholarly journals THE ASESSMENT OF THE SPATIAL AND TEMPORAL DYNAMICS OF AIR TEMPERATURE OF AIR TEMPERATURE IN THE URALS AND WESTERN SIBERIA IN THE SECOND HALF OF THE 20TH-EARLY 21TH CENTURIES WITH THE USE OF REANALYSIS

2021 ◽  
pp. 4-11
Author(s):  
В.В. ФОМИН ◽  
М.Г. УНДЕРСКИХ
Keyword(s):  
Air Temperature ◽  
Western Siberia ◽  
Temporal Dynamics ◽  
Meteorological Data ◽  
Regional Climate ◽  
Time Interval ◽  
The Urals ◽  
Coeffi Cients ◽  
Weather Stations ◽  
Correlation Coeffi

Проведен анализ пространственно-временной динамики приземной среднегодовой температуры воздуха на территории Урала и Западной Сибири по данным 92 метеостанций и реанализов ERA-20С и CERA-20С за период с 1961 по 2010 гг. Установлено, что значения коэффициента корреляции за исследуемый временной промежуток между данными инструментальных метеонаблюдений и данными реанализов ERA-20С и CERA-20С лежат в интервалах 0,81–0,97 и 0,86–0,98 соответственно. Данные по температуре воздуха реанализа CERA-20С лучше согласуются со значениями температуры, полученными на метеостанциях, по сравнению с данными реанализа ERA-20C. В южной части района исследований коэффициенты корреляции ниже, чем в регионах, расположенных севернее. В целом данные реанализа CERA-20C целесообразно использовать при проведении исследований, связанных с климатической изменчивостью и региональным изменением климата Урала и Западной Сибири на участках, находящихся на удалении от метеостанций. The analysis of the spatio-temporal dynamics of the mean annual air temperature in the Urals and Western Siberia on the basis of data of 92 weather stations and reanalysis ERA-20C and CERA-20C for the period from 1961 to 2010 was implemented. It was found that the values of the correlation coeffi cients for the studied time interval between the meteorological data and the data of reanalysis ERA-20C and CERA-20C lie in the intervals of 0,81–0,97 and 0,86–0,98, respectively. The reanalysis of CERA20C is in better agreement with the data obtained at weather stations compared to the reanalysis of ERA20C. In the southern part of the research area, the correlation coeffi cients are lower than in the regions located to the North. In general, data of the CERA-20C. Reanalysis should be used for studies related to climate variability and regional climate change in the Urals and Western Siberia at sites located at a signifi cant distance from weather stations.

scholarly journals Performance Comparison of Geodrain Drainage and Gravel Drainage Layers Embedded in a Horizontal Plane

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6321
Author(s):  
Mariusz Cholewa ◽  
Karol Plesiński
Keyword(s):  
Model Test ◽  
Flow Rate ◽  
Horizontal Plane ◽  
Volumetric Flow Rate ◽  
Performance Comparison ◽  
Test Results ◽  
Water Drainage ◽  
Gravel Layer ◽  
Maximum Value ◽  
Drainage Layers

Drainage materials are widely used, among other uses, in the construction of landfills. Regulations require a drainage layer in the base and a covering for the landfill. The implementation of a gravel drain requires a lot of material and financial outlays. New geocomposite materials are an alternative, and facilitate construction. The aim of the research was to compare the drainage properties of the Pozidrain 7S250D/NW8 geocomposite and gravel drainage. The model test was performed on a specially prepared test stand. The research was carried out for model #1, in which the gravel drainage was built. Model #2 had a drainage geocomposite built into it. The test results show the values of the volumetric flow rate for geodrains, with a maximum value of 40 dm3·min−1. For the gravel layer, values of up to 140 dm3·min−1 were recorded. Another parameter recorded during the damming of water by the embankment was the speed of water suction by the geosynthetic and gravel drainage; the values were 0.067 and 0.024 m3·s−1, respectively. The efficiency of water drainage through the geocomposite was sufficient. It is possible to use the slopes of the landfill for drainage, which will reduce material and financial outlays.

The effect of vertical forces on the coalescence of two dimensional drops

1976 ◽  
Vol 349 (1658) ◽  
pp. 343-354 ◽  
Keyword(s):  
Horizontal Plane ◽  
Vertical Force ◽  
Two Dimensional ◽  
Drainage Time

The effect of a vertical force on the shape of a two dimensional drop approaching a horizontal plane and its homophase has been considered, and the area of the draining film beneath the drop obtained. The force maybe due to a second drop or be applied through a horizontal plane. In this way the effect of the force due to a column of drops in a close-packed dispersion may be estimated. In all the cases considered, the drainage time increases with additional vertical force because the area of the draining film becomes correspondingly greater, implying that the film beneath an undisturbed drop will rupture quicker than when a vertical force presses upon the drop.

Application of direct extended modified algebraic method of Bogoyavlenskii equation on lower and upper bounds in managing and optimizing queues

2020 ◽  
Vol 34 (18) ◽  
pp. 2050166
Author(s):  
Saviour Worlanyo Akuamoah ◽  
Aly R. Seadawy
Keyword(s):  
Queueing Theory ◽  
Queueing Network ◽  
Algebraic Method ◽  
Time Frame ◽  
Semidefinite Optimization ◽  
Upper And Lower Bounds ◽  
Lower And Upper Bounds ◽  
Time Duration ◽  
Maximum Value ◽  
The Common

The common queueing problem has always focused on domestic and industrialized activities. Various improved models of queueing theory are widely used to solve problems. The aim of this paper is to deduce the exact solution of Bogoyavlenskii equation via direct extended modified algebraic method. In addition, we apply it to determine the upper and lower bounds through the semidefinite optimization packages software (SeDuMi). The suggested model indicated strong bounds in reasonable times, we obtain a definite value of [Formula: see text] of the function [Formula: see text] over [Formula: see text] where [Formula: see text] in a time duration less than 60 s and a maximum value of [Formula: see text] where [Formula: see text] in a time frame of approximately 7 min. This study enriches the theoretical optimization queueing network and provides an analysis and decision making method for perfecting the theory.

scholarly journals A Trial to Predict the Diurnal Global Solar Irradiance Received On A Horizontal Plane for Clear Days in Terms of The Solar Angles.

2019 ◽  
Vol 16 (1) ◽  
pp. 344-354
Author(s):  
Samia Sayed Shaban
Keyword(s):  
Distribution Function ◽  
Solar Energy ◽  
Solar Irradiance ◽  
Horizontal Plane ◽  
Present Model ◽  
Meteorological Data ◽  
General Distribution ◽  
Symmetrical Distribution ◽  
Maximum Value ◽  
Length Of The Day

A general distribution function is suggested to predict both symmetrical and asymmetric diurnal global solar irradiance q (t) W/m2 received on a horizontal surface, where “t” is the local day time "h" .The distribution is given in terms of well-established parameters, namely: td :- the length of the solar day expressed in term of the solar angles. tmax :- the time of the day at which the irradiance reaches its maximum value qmax W/m2 for symmetrical distribution  tmax =   i.e.  it occurs at the midday time. td , tmax and qmax are taken as parameters. The suggested expression can be easily integrated along the length of the day time. This gives the daily totals of the received solar energy per unit horizontal area.This is of vital technical importance for solar energy exploitations and applications.  Comparison between computed according to the present model and published experimental meteorological data in Barcelona (Spain), Hong Kong (China), Jeddah and Makah (Saudi Arabia) is given as illustrative examples. Comparison with the published trials for the same locations is also clarified. The introduced model itself gives good fitting for the intermediate interval points of the local day time which is the more effective region.

scholarly journals 137Cs circulation in forest ecosystems on the territory of the Chernobyl exclusion zone (Soil)

2020 ◽  
pp. 85-92
Author(s):  
N.Ye. Zarubina ◽  
Keyword(s):  
Forest Ecosystems ◽  
Specific Activity ◽  
Seasonal Patterns ◽  
Layer By Layer ◽  
Exclusion Zone ◽  
Time Intervals ◽  
Soil Layers ◽  
Temperature And Precipitation ◽  
Coeffi Cients ◽  
Correlation Coeffi

Seasonal changes in the content of 137Cs in soils were studied at three forest ecosystems in the territory of the Chernobyl exclusion zone. The soils were selected layer by layer: A0l, A0f+A0h, 0-5 and 5-10 cm with the frequency of once every two weeks during 2013-2015. Intermittent changes in the levels of the specific activity of 137Cs in all studied soil layers during the calendar year were recorded at the sites. The dependences of the content of 137Cs in different soil layers on the season of the year have not been identified. The calculation of correlation coeffi cients indicates the existence of a relationship between fluctuations in the concentration of radiocaesium only between layers of 0-5 and 5-10 cm. Air temperature and precipitation over different time intervals preceding the sampling do not affect the redistribution of 137Cs in the soil of the forest ecosystems. It has been suggested that the absence of seasonal patterns of changes in the content of 137Cs in soils is associated with its heterogeneity (different amounts of soil biota in each sample).

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