1,341 research outputs found
BODY AERODYNAMICS: CONTRIBUTION TO LONG JUMP PERFORMANCE
A mathematical model of a long jumper flight dynamics is proposed. The model incorporates the factor of the full aerodynamic force exerted during the flight phase under varying conditions. The full aerodynamic force is applied to the body at some angle to the vector of air speed and can be represented as vector sum of drag and lift forces. The magnitudes of the drag and lift components, as well as their role in the length of the jump are affected by a number of parameters, such as flight kinematics, wind velocity, mean altitude, etc., which vary from athlete to athlete, between attempts and competition grounds. Analysis of the video recordings of the jumps of the leading long jumpers were processed using computerized image processing schemes. As the result, the kinematics of the jumps and the aerodynamics of the athletes' bodies at various stages of the flight phase, drag and lift quotients were calculated as the function of the angle of attack of the body, using regression analysis approach. The results obtained make possible determining the influence of the wind velocity and mean altitude. Based on this, the forecast of results and comparable values, derived from the results obtained under specific conditions can be performed. Table gives the results of numerical analysis for three high performance attempts in trial conditions and recalculated to the normalized conditions (zero wind /zero mean elevation). The comparison of the actual and normalized data indicates that the absolute value of the results in long jump during last 24 years might be reconsidered. As another application of the developed model, a series of iso-energetic trajectories was emulated, in order to enhance the performance by optimizing the flight aerodynamics under average conditions
Nonlocal Scalar Quantum Field Theory: Functional Integration, Basis Functions Representation and Strong Coupling Expansion
Nonlocal QFT of one-component scalar field in -dimensional
Euclidean spacetime is considered. The generating functional (GF) of complete
Green functions as a functional of external source , coupling
constant , and spatial measure is studied. An expression for GF
in terms of the abstract integral over the primary field
is given. An expression for GF in terms of integrals
over the primary field and separable Hilbert space (HS) is obtained by means of
a separable expansion of the free theory inverse propagator over the
separable HS basis. The classification of functional integration measures
is formulated, according to which trivial and
two nontrivial versions of GF are obtained. Nontrivial versions
of GF are expressed in terms of -norm and -norm,
respectively. The definition of the -norm generator is suggested.
Simple cases of sharp and smooth generators are considered. Expressions for GF
in terms of integrals over the separable HS with new integrands
are obtained. For polynomial theories and for
the nonpolynomial theory , integrals over the separable HS in
terms of a power series over the inverse coupling constant for
both norms (-norm and -norm) are calculated. Critical values of model
parameters when a phase transition occurs are found numerically. A
generalization of the theory to the case of the uncountable integral over HS is
formulated. A comparison of two GFs , one in the case of
uncountable HS integral and one obtained using the Parseval-Plancherel
identity, is given.Comment: 26 pages, 2 figures; v2: significant additions in the text; prepared
for the special issue "QCD and Hadron Structure" of the journal Particles;
v3: minimal corrections; v4: paragraphs added related to Reviewer comment
Multi-cutter turning process stability analysis
This work displays results of a modelling-based investigation a process of multi-cutter turning process focusing on the stability of nominal steady-state case. The modelling is based on the new surface formation equations, on the equations of motion and on a rational fraction cutting law. The influence of the parameters of the system on the stability of the steady cut is analyzed
Water data analysis: data reduction from beam and ITC info
After recalling the motivation for the analysis of water data, the first stage of data reduction is discussed. This data reduction is based on the selection of protons using beam detector data and ITC information. The resolution of the interaction time in the target which serves as reference for time-of-flight measurement of secondaries, is determined with stable beam optics to be 77 ps, otherwise 106 ps. Cuts, their selection efficiency, event numbers, purity of the data sample after cuts, and some ITC characteristics are presented
Revisiting the 'LSND anomaly' II: critique of the data analysis
This paper, together with a preceding paper, questions the so-called 'LSND
anomaly': a 3.8 sigma excess of antielectronneutrino interactions over standard
backgrounds, observed by the LSND Collaboration in a beam dump experiment with
800 MeV protons. That excess has been interpreted as evidence for the
antimuonneutrino to antielectronneutrino oscillation in the \Deltam2 range from
0.2 eV2 to 2 eV2. Such a \Deltam2 range is incompatible with the widely
accepted model of oscillations between three light neutrino species and would
require the existence of at least one light 'sterile' neutrino. In a preceding
paper, it was concluded that the estimates of standard backgrounds must be
significantly increased. In this paper, the LSND Collaboration's estimate of
the number of antielectronneutrino interactions followed by neutron capture,
and of its error, is questioned. The overall conclusion is that the
significance of the 'LSND anomaly' is not larger than 2.3 sigma.Comment: 30 pages, 16 figures, 6 table
Why the paper CERN-PH-EP-2009-015 (arXiv:0903.4762) is scientifically unacceptable
The paper CERN-PH-EP-2009-015 (arXiv:0903.4762) by A. Bagulya et al. violates
standards of quality of work and scientific ethics on several counts. The paper
contains assertions that contradict established detector physics. The paper
falls short of proving the correctness of the authors' concepts and results.
The paper ignores or quotes misleadingly pertinent published work. The paper
ignores the fact that the authors' concepts and results have already been shown
wrong in the published literature. The authors seem unaware that cross-section
results from the 'HARP Collaboration' that are based on the paper's concepts
and algorithms are in gross disagreement with the results of a second analysis
of the same data, and with the results of other experiments.Comment: 8 pages, 3 figure
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