Morphostructural Characterization of the Heterogeneous Rhodolith Bed at the Marine Protected Area “Capo Carbonara” (Italy) and Hydrodynamics

Mediterranean rhodolith beds are priority marine benthic habitats for the European Community, because of their relevance as biodiversity hotspots and their role in the carbonate budget. Presently, Mediterranean rhodolith beds typically occur within the range of 30–75 m of water depth, generally located around islands and capes, on flat or gently sloping areas. In the framework of a collaboration between the University of Milano-Bicocca and the Marine Protected Area “Capo Carbonara” (Sardinia, Italy), video explorations and sampling collections in three selected sites revealed the occurrence of a well developed and heterogeneous rhodolith bed. This bed covers an area >41 km2 around the cape, with live coverage ranging between 6.50 and 55.25%. Rhodoliths showed interesting morphostructural differences. They are small compact pralines at the Serpentara Island, associated with gravelly sand, or bigger boxwork at the Santa Caterina shoal associated with sand, whereas branches are reported mostly in the Is Piscadeddus shoal, associated with muddy sand. Both in the Santa Caterina shoal and the Serpentara Island, rhodoliths generally show a spheroidal shape, associated with a mean value of currents of 4.3 and 7.3 cm/s, respectively, up to a maximum of 17.7 cm/s at Serpentara, whereas in the Is Piscadeddus shoal rhodolith shape is variable and current velocity is significantly lower. The different hydrodynamic regime, with a constant current directed SW, which deviates around the cape towards E, is responsible for such morphostructural heterogeneity, with the site of the Serpentara Island being the most exposed to a constant unidirectional and strong current. We can associate current velocity with specific rhodolith morphotypes. The morphostructural definition of the heterogeneity of rhodoliths across large beds must be considered for appropriate management policies.

STUDY OF SELF-SUPERPOSABLE LIQUID IN OBLATE SPHEROIDAL SHAPE

The paper studiesthe self-superposable motion of a liquid of a fluid which is incompressible in nature in oblate spheroidal shape. An incompressible fluid is defined as the fluid whose volume or density does not change with pressure. Thus, the main aim of this paper is to solve the basic equations of fluid dynamics in oblate spheroidal coordinates considering self-superposable nature of the fluid. The paper includes the study of nature of vorticity and irrotationality and has not considered the boundary conditions in theanalysis. Lastly, the paper determines the pressure distribution and the solutions contain a set of constants.

Determination of the Parameters of the Target Heterogeneous Medium During Centrifugal Arc Dispersion of Hard Alloys

The article considers the ballistic parameters of the trajectories of high-density alloy particles moving in a gaseous medium, accompanied by a phase transition of the of the particle material. A technique has been developed for determining the parameters of the target depending on the physical and mechanical characteristics of the materials of the captured particles and target layers. The possibility of maintaining the spheroidal shape of particles during the electric arc dispersion of high-density alloys has been determined.

DETERMINATION OF GRAIN MOTION MODE ON A VIBRATORY SURFACE

he use of vibration transport in agricultural production plays a very significant part. Vibratory conveyors have the variety of advantages over traditional transporting ma-chines such as auger and belt type conveyors used at agri-cultural enterprises for transporting mainly loose and granular materials. A rather low wear coefficient of trans-porting body itself - a conveying trough of a vibration-transporting machine may be referred to the advantages, besides, in some constructions of vibration-transporting machines the amount of friction couples is reduced to a minimum. In the design of constructions of vibration-transporting machines a question arises about the determi-nation of motion mode of particles of the transporting mate-rial. Thus, the detection of a predominant component of motion will allow forecasting the wear rate of a transporting surface and the possibility of enlarging the field of techno-logical use of vibration-transporting machines. During the research process for the determination of motion mode of grain material the shape of which was close to spheroid and ellipsoid, the method of mathematical modeling was applied. The system of differential equations of second order was compiled and solved. In the equations the influ-ence of vibration of a transporting surface on the motion of an elliptically shaped body was taken into account. To solve the system the classical method - Runge-Kutta method of the fourth order was used. The program devel-oped in programming language Python allowed identifying the motion mode of the bodies of spheroidal and ellipsoidal shapes on a vibrating surface. As the result, it was deter-mined that the motion of a body of a spheroidal shape on a vibrating surface was possible due to rolling, and the mo-tion of a body of an ellipsoidal shape was achieved be-cause of its sliding on the surface, what follows from wan-ing rotating movements. The suggested method for the determination of motion mode of a body on a vibrating sur-face is rather flexible and may be applied in calculation for larger bodies in comparison with grain seeds.

On a New Analytic Theory of the Moon's Motion III: Further Corrections

Further corrections to the analytic theory of the lunar motion deduced from the first-order approximation to the Lagrange equations of the Sun-Earth-Moon system expressed in relative coordinates and accelerations are evaluated. Those terms arising from the second-order approximation, the planetary perturbations and Earth's spheroidal shape are calculated and bounded, all of them being very small. Finally, Earth's gravitational parameter is calculated from gravity data finding a value slightly higher than that provided by Jet Propulsion Laboratory.

Convective and Microwave Assisted Drying of Wet Porous Materials with Prolate Spheroidal Shape: A Finite-Volume Approach

Convective heating is a traditional method used for the drying of wet porous materials. Currently, microwave drying has been employed for this purpose, due to its excellent characteristics of uniform moisture removal and heating inside the material, higher drying rate, and low energy demand. This paper focuses on the study of the combined convective and microwave drying of porous solids with prolate spheroidal shape. An advanced mathematical modeling based on the diffusion theory (mass and energy conservation equations) written in prolate spheroidal coordinates was derived and the numerical solution using the finite-volume method is presented. Here, we evaluated the effect of the heat and mass transport coefficients and microwave power intensity on the moisture removal and heating of the solid. Results of the drying and heating kinetics and the moisture and temperature distribution inside the solid are presented and discussed. It was verified that the higher the convective heat and mass transfer coefficients and microwave power intensity, the faster the solid will dry and heat up.

О силе электростатического взаимодействия между двумя проводящими сфероидами

Application of finite element method for calculation of electrostatic interaction force of two conducting bodies of spheroidal shape with preset charges on their surfaces in zero external field is considered.

ZnO Microflowers Grown by Chemical Bath Deposition: A Low-Cost Approach for Massive Production of Functional Nanostructures

The massive production of nanostructures with controlled features and high surface area is a challenging and timely task in view of developing effective materials for sensing and catalysis. Herein, functional ZnO nanostructures, named microflowers (MFs) have been prepared by a facile and rapid chemical bath deposition. ZnO MFs show an intriguing sheets-composed spheroidal shape, with diameters in the range 0.2–2.5 µm, whose formation is achieved by a complexing action by F in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine. The evolution of the physical and structural properties of the material, following post-deposition thermal annealing, has been investigated by scanning electron microscopy (SEM), energy dispersive X-ray analyses (EDX), photoluminescence (PL) and X-ray diffraction (XRD) techniques. The effectiveness of ZnO MFs in UV detection has also been tested to account for the potentiality of these nanostructures.