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In a lecture hall it is vital to assure proper teaching conditions meaning that the information from the speaker/teacher must be received correctly by the listeners. Speech intelligibility is the main objective when a lecture hall is evaluated. In this paper, the authors discuss the importance of the acoustics of a lecture hall and the influence of various parameters over speech transmission from the speaker – the professors to the listeners – the students. The number of acoustical parameters is very large, but Speech Transmission Index (STI) and Reverberation Time (RT) are commonly used to evaluate the acoustics of a teaching room. Other parameters like room geometry and seat placement have great influence in speech intelligibility. As an example, a lecture hall of 120 seats from Naval Academy „Mircea cel Batran“ is investigated using virtual simulations with ODEON software. The results of the simulations are discussed and some remarks are made regarding the current condition of the lecture hall. [ABSTRACT FROM AUTHOR]

The upsurge in the value of wind energy in Romania may have occurred due to a constructive development of wind turbines, their dimensions and the increase in their number of units in wind farms. The modern design of large wind turbines, corroborated with an appropriate wind speed leads to a significant production of green energy. In order to obtain a greater amount of energy, modern turbines are fitted with many devices which are exploited by high-tech electronic circuits. Instruments of remote detection, measurement devices and control processes of the main measurement systems are based on various types of electronic apparatus. These appliances are very sensitive to tension variation caused by abnormal conditions of turbine operation and by the national electrical grid which the wind farm is connected to. The paper aims at providing an assessment of a wind farm registers as well as a set of methods meant to overcome such obstacles related to designing large wind turbines. Similarly, the paper offers a classification of the various types of abnormalities that appear in the installation connected to the electric grid, such as a sudden power cut, unplugging or tension variation. The difficulty of such an impact is to be determined for every type of disorder associated to electronic glitches occurring in wind turbines. [ABSTRACT FROM AUTHOR]

In order to conduct electromagnetic field measurements on board a ship four different locations have been used: the upper deck; the aft; the command point- exterior; the navigating bridge - inside. Within each location measurements were performed with different stations located in broadcasting, on different frequency ranges and operating modes (AM - amplitude modulation and FM - frequency modulation), depending on the available sensors. The measurements made on the ship targeted the following frequency ranges: 88-200 MHz, 200-2500 MHz. Measurements carried out on the vessel gaved data on: the electric field E [V / m], for different frequency ranges; the electric field [dBµV / m]; rate exposure; ER: E2/L2; field strength limit, L [V / m]; measurement error, ER * 1000 [‰]; electromagnetic power flux density, PD (or S) [µW / cm2]; total field strength (RMS) [V / m]; maximum single [V / m]. [ABSTRACT FROM AUTHOR]

In recent years more and more studies have shown that, the low frequency field strength (particularly magnetic, 50 / 60Hz) are a major risk factor; according to some specialists - even more important as the radiation field. As a result, the personnel serving equipment and facilities such as: electric generators, synchronous, the motors, the inverters or power transformers is subjected continually to intense fields, in their vicinity, with possible harmful effects in the long term by affecting metabolism cell, respectively, the biological mechanisms. Therefore, finding new methods and tools for measurement and analysis of low frequency electromagnetic fields may lead to improved standards for exposure limits of the human body. [ABSTRACT FROM AUTHOR]

A ship plant consisting in a three-phase AC asynchronous motor is well known onboard a ship. The steady-state numerical model helps to study the transitory phenomena's regarding power supply network. [ABSTRACT FROM AUTHOR]

The steering gear of a ship is an important system used for controlling speed and angle of a propeller. The purpose of the article is to present the speed regulation of DC motor (increase and decrease speed) used for the ship steering gear system. [ABSTRACT FROM AUTHOR]