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Constantza Maritime University

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Memet F.,Constantza Maritime University
European Journal of Science and Theology | Year: 2017

Nowadays, renewable energy is attractive for investors and also for society. Still, there are needed actions for the population awareness and environmental education. Internationally, religions started to have also an environmental mission, but maybe they should be involved in this issue more seriously. This study is presenting the results of a survey between the Romanian members of the Cross-Border Green Energy Cluster Romania-Bulgaria, investigating a potential link between beliefs of the members and environmental values. The questionnaire was structured on three sets of aspects: religious identity, relationship humans-environment and relationship self-involvement-environmental quality. Although the survey is at scale small-34 participants, it resulted that there are represented people from Orthodox and Muslim communities, sharing many times the same opinion on religious and environmental attitudes. © 2016, Ecozone, OAIMDD. All rights reserved.


Danisor A.,Constantza Maritime University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

This paper proposes an analysis, especially in time domain, of the electrical noise existent on the power distribution lines. This study is important for the use of powerlines as a channel of information transmissions. This information may refer to analog signals and as well to digital signals. The main problem addressed in this paper consists in the characterization of the background noise and to establish his statistical proprieties. It is very important to know if the noise induced in the transmission channel is a stationary one, or even an ergodic one. The main parameters like the mean value, the mean square value were determined in this paper. The approximation of the probability density function of each statistical parameter was studied. The pulses induced in the transmission channel by the transient phenomena of the power electrical systems were considered deterministic signals and their contributions were not included in this study. © 2016 SPIE.


Danisor A.,Constantza Maritime University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

In this paper we propose an analysis of the possibilities of spikes detection which appears on the power lines of electrical distribution. The importance of this problem consists in the possibility of surveillance at distance the regimes of power electrical motors. This regime was studied in an industrial network which supplies the power pumps necessary to assures a city water consumption. We consider the industrial electrical networks as a linear, time invariant and causal system which has a certain response to the electrical spikes, assimilates with Dirac impulses. For that reason the output signal represents the impulse response of the system. The main problem is to detect this signal and to establish the moments of its presence. To detect and extract the useful signal linear methods like fourier transform or Short Time Fourier Analysis are not very relevant. A more efficient method to detect the spikes presence consists in using quadratic detectors in timefrequency domain, like detectors based on Wigner-Ville transform or detectors based on Ambiguity Function. In this paper we tried to present the advantages of these last detectors. © 2016 SPIE.


Andrei C.,Constantza Maritime University
IOP Conference Series: Materials Science and Engineering | Year: 2017

Intact ship stability assessment to prevent stability failure in heavy weather conditions is of paramount importance on board vessel. The possibility of assessment the causes that can lead to loss of ship's stability as well as the assessment of intact stability in heavy seas is a important problem and has attracted a huge interest of the national and international regulatory authorities. Despite the regulations in force, referring to intact ship stability, many ships continued to lose the stability and or capsize due to failure modes that presently are not covered by such regulations. Based on this aspect has been identified the necessity of modelling an updated criteria for assessment of ship's stability taking into consideration actual possible situations for loss of stability in heavy seas as a measure of increasing she safety of ships. In this respect, the goal of this paper is to illustrate a possible criteria for assessment ship's stability in heavy seas through a method of determination the possible problems in a form of dynamic stability criteria. A new intact stability criteria is proposed and developed based on separate levels for assessment of vulnerability and susceptibility of ships in situations of parametric rolling and pure loss of stability encountered in extreme sea conditions. Mathematical models correlated with ship's construction particulars and weather conditions were developed for every separate level in order to assess the ship's stability. The objective of the proposed criteria is to bring to officers on board ships the possibility of assessment the ship's intact stability, as a measure of prevention and improvement of safety during the voyage. © Published under licence by IOP Publishing Ltd.


Stan L.C.,Constantza Maritime University
IOP Conference Series: Materials Science and Engineering | Year: 2017

This paperwork tried to simulate the combustion inside the marine engines using the newest computer methods and technologies with the result of a diverse and rich palette of solutions, extremely useful for the study and prediction of complex phenomena of the fuel combustion. The paperwork is contributing to the theoretical systematization of the area of interest bringing into attention a thoroughly inventory of the thermodynamic description of the phenomena which take place in the combustion process into the marine diesel engines; to the in depth multidimensional combustion models description along with the interdisciplinary phenomenology taking place in the combustion models; to the FEA (Finite Elements Method) modelling for the combustion chemistry in the nonpremixed mixtures approach considered too; the CFD (Computational Fluid Dynamics) model was issued for the combustion area and a rich palette of results interesting for any researcher of the process. © Published under licence by IOP Publishing Ltd.


Stinga V.-G.,Constantza Maritime University
IOP Conference Series: Materials Science and Engineering | Year: 2017

Transport networks are studied most of the time from a graph theory perspective, mostly studied in a static way, in order to emphasize their characteristics like: topology, morphology, costs, traffic flows etc. There are many methods used to describe these characteristics at local and global level. Usually when analysing the transport network models, the aim is to achieve minimum capacity transit or minimum cost of operating or investment. Throughout this paper we will get an insight into the many models of the transport network that were presented over the years and we will try to make a short analysis regarding the most important ones. We will make a case study on finding the optimal route by using one of the models presented within this paper. © Published under licence by IOP Publishing Ltd.


Tamas R.D.,Constantza Maritime University
2016 International Workshop on Antenna Technology, iWAT 2016 | Year: 2016

Previously, the author has described a method for measuring the antenna gain in non-anechoic sites. The effects of reflection and diffraction on the neighboring objects can be dramatically reduced by averaging, over a set of distances, a normalized transfer function of the system consisting of the antenna under test and the measuring antenna. The method was successfully tested on dipole type, ultra-wide band antennas. This paper, presents further results on measuring narrow band, monopole antennas. It comes out that averaging does not remove the effect of the diffraction on scatterers close to the radiating element, such as the edges of the antenna ground plane; conversely, it reasonably reduces the effects of scatterers placed at several wavelengths away from the antenna under test. © 2016 IEEE.


Scupi A.A.,Constantza Maritime University
IOP Conference Series: Materials Science and Engineering | Year: 2016

This paper is conceived on the idea that numerical programs using computer models of physical processes can be used both for scientific research and academic teaching to study different phenomena. Computational Fluid Dynamics (CFD) is used today on a large scale in research and academic institutions. CFD development is not limited to computer simulations of fluid flow phenomena. Analytical solutions for most fluid dynamics problems are already available for ideal or simplified situations for different situations. CFD is based on the Navier- Stokes (N-S) equations characterizing the flow of a single phase of any liquid. For multiphase flows the integrated N-S equations are complemented with equations of the Volume of Fluid Model (VOF) and with energy equations. Different turbulent models were used in the paper, each one of them with practical engineering applications: the flow around aerodynamic surfaces used as unconventional propulsion system, multiphase flows in a settling chamber and pneumatic transport systems, heat transfer in a heat exchanger etc. Some of them numerical results were validated by experimental results. Numerical programs are also used in academic institutions where certain aspects of various phenomena are presented to students (Bachelor, Master and PhD) for a better understanding of the phenomenon itself. © Published under licence by IOP Publishing Ltd.


Constantin S.L.,Constantza Maritime University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

This study presents numerical and experimental results concerning a test impeller of a centrifugal pump. From the experimental point of view, the cavitation was visualized at different Inlet Pressure values. Image processing and statistical treatment of the photographs taken at given impeller position allowed to quantify the attached and cloud cavitation extent. A numerical model of 3D cavitating flows, based on the CFD code Fluent 6.1, has been developed to predict the cavitation behavior in the presented model which is considering the entire pump, the impeller and also the casing of the pump, with all its complex geometry and flow parameters. Non-cavitating and cavitating conditions were investigated. Calculations were found to be in good agreement with experimental measurements and visualisations. Experimental and numerical results concerning the pump parameters were investigated. The overall conclusion is the obvious knowledge that the Net Positive Suction Head (NPSH) is indeed affecting the cavitation condition in the centrifugal pumps, having direct impact on the magnitude of static pressures in various locations inside the pump, but is not altering too much the velocities distributions of fluid. © 2012 SPIE.


Ciucur V.-V.,Constantza Maritime University
Electronics and Electrical Engineering - Proceedings of the Asia-Pacific Conference on Electronics and Electrical Engineering, EEEC 2014 | Year: 2015

The control system for the speed position of a DC motor, generally can be controlled by a microprocessor, or microcomputer, all these components which can determine the values for speed for each movement and passes. The system can contain a D/A converter. In order to obtain signals which can then be processed by a converter an optical encoder can be used, mounted on the shaft of a DC motor. © 2015 Taylor & Francis Group, London.

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