Phyllosoma larvae and the phylogeny of Palinuroidea (Crustacea: Decapoda): A review

1994 ◽  
Vol 45 (6) ◽  
pp. 925 ◽  
Author(s):  
JA Baisre
Keyword(s):  
Deep Water ◽  
Coastal Waters ◽  
Point Of View ◽  
Larval Morphology ◽  
Larval Life ◽  
Evolutionary Scheme ◽  
Well Differentiated ◽  
Phyllosoma Larvae ◽  
Phylogenetic Scheme ◽  
Good Agreement

A review of larval morphology of some 50 species belonging to 15 of the 16 existing genera of Palinuroidea is presented. The taxonomic value of larval characters of the group is discussed, and a phylogenetic scheme of the whole group has been attempted. Phylogenetic and phenetic data obtained during this review show good agreement with a previously published evolutionary scheme for the Palinuridae based on adult characters, although Palinurus seems to be a more primitive genus than Palinustus and Justitia. From the point of view of larval morphology, Palinurellus (Synaxidae) seems to be the most primitive genus. Data on evolution of the Scyllaridae show three well differentiated groups: the more primitive (as typified by the larvae) Scyllarides-Arctides-Parribacus and Ibacus-Evibacus groups and the more specialized Thenus-Scyllarus group. Larval morphology also suggests that Parribacus is closer to Scyllarides and Arctides than to the Ibacus-Evibacus group. Evolution in Palinuroidea is seen as a process of radiation of the deep-water genera to coastal waters with a progressive shortening of larval life, although secondary trends towards shortening of larval life have also occurred in the more primitive deep-water genera (Puerulus, Linuparus and Palinurus).

ANALYSIS OF THE FUNCTIONING OF MARINE ECOSYSTEMS ON CHANGING THE PARAMETERS OF THE BIOLUMINESCENCE FIELD ON THE CRIMEAN BLACK SEA SHELF

2017 ◽  
Author(s):  
Svetlana Rubtsova ◽  
Svetlana Rubtsova ◽  
Natalya Lyamina ◽  
Natalya Lyamina ◽  
Aleksey Lyamin ◽  
...  
Keyword(s):  
Black Sea ◽  
Field Intensity ◽  
Deep Water ◽  
Coastal Waters ◽  
Integrated Management ◽  
Abiotic Factors ◽  
Environmental Safety ◽  
The Black Sea ◽  
Intensity Increase ◽  
First Time

The concept of a new approach to environmental assessment is offered in the system of integrated management of the resource and environmental safety of the coastal area of the Black Sea. The studies of the season and daily changeability in the bioluminescence field in the Sevastopol coastal waters has been conducted. For the first time considerable differences in the bioluminescence field seasonal changes in the surface and deep water layers and the reasons conditioning this phenomenon have been shown, using a method of multidimensional statistical analysis. The bioluminescence field vertical profile change in the Black sea coastal waters in the autumn period at night has been studied. It has been shown that according to the character of bioluminescence parameters dynamics a water column can be divided into layers: upper (0 – 35 m) and deep water (36 – 60 m). It has been revealed that life rhythms of the plankton community are the main reason for the bioluminescence field intensity variability. It has been revealed that 14-hour periodicity of the bioluminescence field is related to the changes in light and its variations with 2,5…4,5 hours are conditioned by planktonts endogenous daily rhythms. And here biotic factors effect mostly periodicity of the bioluminescence field intensity increase and fall down at the dark time of the day. Abiotic factors are of less importance in circadian rhythmic of the bioluminescence field in the neritic zone.

Structural Analysis of an Offshore Jacket Model Under Seismic Excitation

2008 ◽  
Author(s):  
Helder J. D. Correia ◽  
Anto´nio C. Mendes ◽  
Carlos A. F. S. Oliveira
Keyword(s):  
Point Of View ◽  
Shaking Table ◽  
Seismic Excitation ◽  
Model Structure ◽  
Structural Members ◽  
Jacket Structures ◽  
Reaction Forces ◽  
Nodal Displacements ◽  
Good Agreement

In the present work the action of earthquakes upon offshore jacket structures is analysed by means of ADINA software. Our case-study refers to an existing model structure, previously constructed at the Laboratory of Fluid Mechanics of UBI, which has been analysed from the hydrodynamic point of view — Mendes et al. [1, 2]. The seismic excitation will be imposed at the base of this model structure, with frequencies and amplitudes corresponding to actual earthquake conditions transposed to the model scale of 1:45. The FEM software is utilised to calculate the natural frequencies of the model and to obtain stresses at selected members, as well as their nodal displacements. Our purpose is to quantify maximum stresses occurring in critical structural members and to verify the survivability criterion. The predictions of the numerical model, in terms of the reaction forces at the base and acceleration at the top of the structure, are then correlated with the experimental measurements performed when the model structure is excited in an especially designed shaking table (Correia [3]), revealing a good agreement between both results.

scholarly journals The Physical and Thermodynamic Functions of Borides

2017 ◽  
Vol 18 (1) ◽  
pp. 58-63
Author(s):  
N.Yu. Filonenko
Keyword(s):  
Free Energy ◽  
Physical Properties ◽  
Thermodynamic Functions ◽  
Point Of View ◽  
Energy Potential ◽  
High Temperature Expansion ◽  
Temperature Dependences ◽  
Function Calculation ◽  
First Time ◽  
Good Agreement

In the paper the physical properties and thermodynamic functions of borides Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr) are studied with accounting for fluctuation processes. We use the microstructure analysis, the X-ray structural and the durometric analyses to determine the physical properties of alloys. In the paper it is determined the phase composition and physical properties of borides. In this paper for the first time it is determined the thermodynamic functions of borides using the Hillert and Staffansson model with accounting for the first degree approximation of high-temperature expansion for the free energy potential of binary alloys. We obtain the temperature dependences for such thermodynamic functions as Gibbs free energy, entropy, enthalpy and heat capacity Ср along with their values at the formation temperature for Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr). The approach under consideration enables to give more thorough from the thermodynamic point of view description of borides formed from the liquid. The outcomes of the thermodynamic function calculation for borides are in good agreement with experimental data and results of other authors.

Optimization of Trimaran Design Configuration in Calm and Deep Water

2020 ◽  
Author(s):  
Renato Skejic ◽  
Sverre A. Alterskjær
Keyword(s):  
Deep Water ◽  
Optimization Procedure ◽  
Wave Theory ◽  
Point Of View ◽  
Engineering Practice ◽  
Total Resistance ◽  
Operational Parameters ◽  
Viscous Effects ◽  
Greenhouse Gasses ◽  
Hard Particles

The field of sea based modern shipping activities is constantly seeking for its improvements to achieve the economically justified operational patterns. In the same time, the sea transportation activities also need to satisfy currently imposed and, as well as, upcoming in the near future, safety and ecologically friendly footprint characteristics when it comes to the emission of greenhouse gasses and hard particles [1]. Fulfilment of the stated requirements consequently asks for the determination of certain vessels operational parameters such as the total resistance of a vessel which estimation is frequently carried out for predefined calm and deep-water environmental scenario. Current work is dealing with investigation of the total resistance parameter in calm and deep water for the preselected types of the trimaran ship hull configurations. The total resistance is estimated according to [2] recommended procedure through applicability of the robust and reliable method which is capable to address the problem of wave resistance prediction in calm and deep water. The method has origin in ordinary and modified Michell thin – ship wave theory by considering the viscous effects [3]. The differences between the utilized theories are discussed from the qualitative and quantitative point of view of the obtained results in comparison to the open source available theoretical experimental data and from the perspective of common engineering practice. Finally, based on the above description, the performed total resistance studies are used as a base for formulation of the optimization procedure which may be used in the trimaran vessel preliminary designs in the range of the forward speeds commonly expected during the normal operational life of the investigated trimaran vessel.

Sound Propagation in Dilute Polyatomic Gases

1972 ◽  
Vol 27 (4) ◽  
pp. 583-592
Author(s):  
H. Moraal ◽  
F. Mccourt
Keyword(s):  
Pressure Range ◽  
Sound Propagation ◽  
Plane Waves ◽  
Point Of View ◽  
Perturbation Function ◽  
Sound Waves ◽  
Polyatomic Gas ◽  
Measured Pressure ◽  
Theory And Experiment ◽  
Good Agreement

Abstract Sound propagation in dilute pure gases, both monatomic and polyatomic, has been considered from the point of view of the Waldmann-Snider equation. It is shown that the commonly employed assumption that sound propagation in gases is equivalent to the propagation of plane waves is valid only in the region where collisions restore equilibrium faster than it is perturbed by the sound waves. A systematic truncation procedure for an expansion of the perturbation function in irreducible Cartesian tensors is introduced and then illustrated in solutions for three specific kinds of molecules, helium, nitrogen and rough spheres. The agreement between theory and experiment is rather good for sound absorption in the region where the ratio of the collision and sound frequencies is greater than 1.5. The agreement in the case of dispersion is good over the whole measured pressure range. One useful result obtained is to show the polyatomic gas calculations in second approximation have as good agreement with experiment as the calculations for noble gases in third approximation. This can be related to the possession by the polyatomic gas of a bulk viscosity which dominates in sound propagation.

scholarly journals A Depth-Bistatic Bottom Reverberation Model and Comparison with Data from an Active Triplet Towed Array Experiment

2020 ◽  
Vol 10 (9) ◽  
pp. 3080
Author(s):  
Youngcheol Jung ◽  
Woojae Seong ◽  
Keunhwa Lee ◽  
Seongil Kim
Keyword(s):  
Time Series ◽  
Deep Water ◽  
Water Environment ◽  
Ray Theory ◽  
Reverberation Time ◽  
Environment Model ◽  
Line Array ◽  
Model Predictions ◽  
Towed Array ◽  
Good Agreement

In this paper, a depth-bistatic bottom reverberation model that employs the ray theory is presented. The model can be applied to an active towed array in the ocean. The reverberation time series are modeled under the depth-bistatic assumption and their Doppler shift is calculated based on the actual source–receiver geometry. This model can handle N × 2D range-dependent bathymetry, the geometry of a triplet array, and the Doppler motion of the source, targets, and receiver. The model predictions are compared with the mid-frequency reverberation data measured by an active triplet towed array during August 2015 in the East Sea, Korea. These data are collected with a variable depth source at mid-frequency and the triplet line array in a deep-water environment. Model predictions of the beam time series and its spectrogram are in good agreement with the measurement. In particular, we discuss the effects of the source and receiver depths on the reverberation in deep water observed in both the measured and modeled results.

Deep-Submergence Archaeology

2012 ◽  
Author(s):  
Shelley Wachsmann
Keyword(s):  
Deep Water ◽  
Coastal Waters ◽  
Gradual Transition ◽  
Cultural Resources ◽  
Archaeological Excavations

Coastal waters represent the greatest danger to ships and seafarers, as ships are most commonly lost at the intersection of water and shore. Ships sinking in deep water undergo a gradual transition. Deep-submergence archaeology refers to the archaeological study of cultural resources beyond the limits of traditional diving. The totality of archaeological exploration at great depths—discovering, recording, excavating, and recovering—requires function-specific tools. Deep Submergence Archaeological Excavations (DSAE) takes advantage of a remarkable existent toolkit, designed for a variety of oceanographic purposes other than the study of ancient shipwrecks. What is lacking at present is a comprehensive methodology for deepwater excavation. The ultimate goal of DSAE is to develop the technologies and the skills that permit expeditions to excavate and safely raise the contents and hull of an entire ship for conservation, study, and display.

Elasto-plastic analysis of a rotating model conical turbine disc

1975 ◽  
Vol 10 (3) ◽  
pp. 167-171 ◽  
Author(s):  
F Ginesu ◽  
B Picasso ◽  
P Priolo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Limit Analysis ◽  
Point Of View ◽  
Complete Analysis ◽  
The Finite Element Method ◽  
Computational Simplicity ◽  
Rotating Shell ◽  
Good Agreement ◽  
Element Method

Results on the plastic collapse behaviour of an axisymmetric rotating shell, obtained by Limit Analysis and the Finite Element Method, are in good agreement with experimental data. The Finite Element Method, though computationally rather costly, permits, however, a more complete analysis of elasto-plastic behaviour. For the present case, the Limit Analysis has the advantage of greater computational simplicity and leads to a quite satisfactory forecast of collapse speed from the engineering point of view.

Growth dynamics of the deep-water Asian eelgrass, Zostera asiatica, in the eastern coastal waters of Korea

2016 ◽  
Vol 51 (4) ◽  
pp. 613-625
Author(s):  
Jung-Im Park ◽  
Jong-Hyeob Kim ◽  
Su Hyun Park
Keyword(s):  
Deep Water ◽  
Coastal Waters ◽  
Growth Dynamics

Die Druckverbreiterung der diffusen Heliumlinien, Vergleich zwischen Messung und Theorie im quasistatischen Bereich

1966 ◽  
Vol 21 (6) ◽  
pp. 697-718 ◽  
Author(s):  
H. Pfennig ◽  
E. Trefftz
Keyword(s):  
Stark Effect ◽  
Point Of View ◽  
Spectral Lines ◽  
Experimental Point ◽  
Line Profiles ◽  
Experimental Conditions ◽  
Part D ◽  
Upper Level ◽  
Good Agreement ◽  
Red Wing

It is difficult to discriminate between theories of pressure broadening of spectral lines through comparison with experiments. Line profiles are insensitive with respect to details of the theory, and it is difficult to keep experimental conditions clear and certain enough to make the comparison relevant. We used measurements of VIDAL 1 which are satisfactory from the experimental point of view. The wings of the diffuse He-lines 2P — nD are compared with those calculated by quasistatic theory. Part B deals with STARK effect splitting of the upper level. Part C describes the quasistatic theory of the line wings, and discusses the probability function of the so called micro field strength. In part D the results of the calculation are compared with the measurements. The comparison is relevant only for the violet wings of the triplet series. The red wing of the triplet lines and the violet wing of the singlet lines are disturbed by the forbidden component 2P — nP. The red wing of singlet lines is experimentally too inexact because of disturbing wings of neighboring triplet lines. The slope of the violet side of the triplet wings shows good agreement between theory and measurement for the far wing (large Δv). For decreasing Δv the experimental curve stays below the theoretical curve. For comparison of wing intensities it proves to be important to normalize the line profiles. It is seen that the measured height of the wings increases less with increasing main quantum number than the theoretical height.

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