scholarly journals Grouns for the possibility of operation of some cargo vessels in Onezhskoe and Ladozhskoe lakes without hatch covers

2020 ◽  
pp. 36-47
Author(s):  
Stanislav N. Girin
Keyword(s):  
Theoretical Calculations ◽  
Model Tests ◽  
Total Strength ◽  
Hydraulic Filling ◽  
Operational Safety ◽  
Russian River

The requirements of the Rules of the Russian River Register on equipping cargo ships of all classes operating in the basins of Onega and Ladoga lakes with hatch covers for cargo holds are stated. The possibility of withdrawing the requirements on using hatch covers provided for by the Rules of the River Register is used by proving the equal operational safety of ships of the projects under consideration without hatch covers. The barges of projects 461G, R85, 81060, designed for loading bulk cargo by hydraulic filling and without hatch covers of cargo holds are considered. To prove the possibility of their operation in these basins without hatch covers, the results of model tests of ships in the experimental pool, as well as theoretical calculations of the total strength and emergency stability are used. The results obtained can be used by shipping companies that have vessels of these projects.

Study of Motion Performance of a Floating System With Four Moonpools and a VAWT

2021 ◽  
Author(s):  
Lei Tan ◽  
Satsuya Moritsu ◽  
Tomoki Ikoma ◽  
Yasuhiro Aida ◽  
Koichi Masuda
Keyword(s):  
Potential Theory ◽  
Theoretical Calculations ◽  
Model Tests ◽  
Hydrodynamic Performance ◽  
Linear Potential ◽  
Gyroscopic Effect ◽  
Floating Foundation ◽  
Motion Responses ◽  
Floating System ◽  
Linear Potential Theory

Abstract In this paper the hydrodynamic performance of a barge-type floating foundation installed with four moonpools and a VAWT was investigated through model tests and theoretical calculations. The characteristics of wave-induced motion responses and tether tensions and the effects of turbine rotations were examined. Physical model tests were conducted in a wave tank using regular waves with the wave period ranging from 0.6 to 1.6 seconds and 0.01 or 0.02 meters in amplitude. A 2-MW-class VAWT was modelled with a scale ratio of 1/100 in the experiments. By varying the mass and the rotational speed of the turbine, gyroscopic moment effects were studied. In addition, numerical calculations based on the linear potential theory and Green function method were carried out to estimate motion responses and tether tensions. The present results indicate that the gyroscopic effect due to turbine rotations can be profound. It was found that the first-order motions of the floating system were substantially reduced by the gyroscopic effect, while the second-order motions and tether tensions may be significantly increased. Moreover, the viscous damping of water motions in moonpools was found not negligible. As a result, theoretical models based on linear potential theory should be used with care in hydrodynamic analysis with regard to the floating systems with VAWT rotations. In addition, the present in-house program code was validated against WAMIT through comparing hydrodynamic predictions of a floating foundation with four moonpools, with reasonable agreement.

Study on Model Tests of Desilting Tunnel of Longkou Power Station

2013 ◽  
Vol 353-356 ◽  
pp. 2463-2467
Author(s):  
Min Wang ◽  
Yong Xin Wu
Keyword(s):  
Comparative Analysis ◽  
Adverse Effects ◽  
Theoretical Calculations ◽  
Model Tests ◽  
Hydropower Station ◽  
Power Station ◽  
Design Program ◽  
Hydraulic Conditions ◽  
Design Type

The paper made a comprehensive introduction in model tests of the desilting tunnel of Longkou hydropower station, including prototype information, experimental purposes and content, then doing the comparative analysis of the theoretical calculations and data that observing by instruments. The tests results show that it is reasonable that desilting tunnel overall layout and the design type of the desilting tunnel, the various hydraulic elements that under various hydraulic conditions and the flow pattern of upstream and downstream have no serious adverse effects on desilting tunnel itself and other buildings, it play a role of support and verification to the design program.

XUV Absorption Spectra of Carbon Ions

1988 ◽  
Vol 102 ◽  
pp. 71-73
Author(s):  
E. Jannitti ◽  
P. Nicolosi ◽  
G. Tondello
Keyword(s):  
Absorption Spectra ◽  
Cross Section ◽  
Theoretical Calculations ◽  
Photoionization Cross Section ◽  
Carbon Ions

AbstractThe photoabsorption spectra of the carbon ions have been obtained by using two laser-produced plasmas. The photoionization cross-section of the CV has been absolutely measured and the value at threshold, σ=(4.7±0.5) × 10−19cm2, as well as its behaviour at higher energies agrees quite well with the theoretical calculations.

Relative Intensities in ED Patterns From Thin Gold Films

1972 ◽  
Vol 30 ◽  
pp. 636-637
Author(s):  
R. H. Morriss ◽  
J. D. C. Peng ◽  
C. D. Melvin
Keyword(s):  
Theoretical Calculations ◽  
Diffraction Theory ◽  
Gold Films ◽  
Reasonable Accuracy ◽  
Experimental Conditions ◽  
Crystal Perfection ◽  
Heavy Atoms ◽  
Fine Focus ◽  
Convergent Beam ◽  
Beam Diffraction

Although dynamical diffraction theory was modified for electrons by Bethe in 1928, relatively few calculations have been carried out because of computational difficulties. Even fewer attempts have been made to correlate experimental data with theoretical calculations. The experimental conditions are indeed stringent - not only is a knowledge of crystal perfection, morphology, and orientation necessary, but other factors such as specimen contamination are important and must be carefully controlled. The experimental method of fine-focus convergent-beam electron diffraction has been successfully applied by Goodman and Lehmpfuhl to single crystals of MgO containing light atoms and more recently by Lynch to single crystalline (111) gold films which contain heavy atoms. In both experiments intensity distributions were calculated using the multislice method of n-beam diffraction theory. In order to obtain reasonable accuracy Lynch found it necessary to include 139 beams in the calculations for gold with all but 43 corresponding to beams out of the [111] zone.

Effects of Higher-Order Laue Zone reflections on structure images

1993 ◽  
Vol 51 ◽  
pp. 450-451
Author(s):  
H. S. Kim ◽  
S. S. Sheinin
Keyword(s):  
Wave Vector ◽  
Theoretical Calculations ◽  
Reciprocal Lattice ◽  
Image Plane ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Higher Order ◽  
Lattice Image ◽  
Lattice Vector ◽  
Image Position

The importance of image simulation in interpreting experimental lattice images is well established. Normally, in carrying out the required theoretical calculations, only zero order Laue zone reflections are taken into account. In this paper we assess the conditions for which this procedure is valid and indicate circumstances in which higher order Laue zone reflections may be important. Our work is based on an analysis of the requirements for obtaining structure images i.e. images directly related to the projected potential. In the considerations to follow, the Bloch wave formulation of the dynamical theory has been used.The intensity in a lattice image can be obtained from the total wave function at the image plane is given by: where ϕg(z) is the diffracted beam amplitide given by In these equations,the z direction is perpendicular to the entrance surface, g is a reciprocal lattice vector, the Cg(i) are Fourier coefficients in the expression for a Bloch wave, b(i), X(i) is the Bloch wave excitation coefficient, ϒ(i)=k(i)-K, k(i) is a Bloch wave vector, K is the electron wave vector after correction for the mean inner potential of the crystal, T(q) and D(q) are the transfer function and damping function respectively, q is a scattering vector and the summation is over i=l,N where N is the number of beams taken into account.

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