1,721,090 research outputs found
Outdoor Noise Generated by Ships: Identification of a procedure for prediction of outdoor ship noise in harbour
No full textPrimary aim of the study is to better knowledge about the outdoor ship noise process in order to propose appropriate actions for reducing noise emissions in the environment and new uniform criteria and limits for noise radiated by ships into the harbours of European Union.
To attain this purpose, first of all, designers need to individuate all the ship’s noise sources and to establish and define an appropriate measurement procedure for quantifying noise radiated to harbour. After this, noise generated in open field conditions by different ships should be measured in order to create a specific database of the actual noise levels in harbours. A deeper knowledge of the actual noise pollution in European harbours should allow to establish appropriate noise limits consistent with the current technology and in accordance with people health.
Furthermore, the scientific community has to determine the computational tools which should allow designers to predict outdoor noise of ships during design phase.
In this report, a new operative procedure elaborated at the University of Trieste is presented. The study has been developed by taking advantage of experience gained on the subject by the Noise and Vibration Department of Fincantieri SpA.
In the following, a brief introduction is given: basics about ship’s noise sources in Chapter 2, fundamental principles of theoretical methods for dealing with noise field generated by ships in Chapter 3, and computational tool selected for carrying out simulations in Chapter 4. In Chapter 5 each step of the proposed procedure is presented in detail and all assumptions at the basis of the operative flow chart and of the numerical model are justified. Finally, a case study, which has been carried out on a passenger ship in harbour, is discussed in detail in Chapter 6. Suggestions for a proper use of the method and guidance on how to interpret simulation outputs in the post-processing phase are given in the same chapter. General conclusion and suggestions for future work close the report in Chapter 7
Numerical simulation for prediction of airborne outdoor ship noise in harbour
No full textIn past decades European ports have become increasingly complex industrial areas. From simple piers for loading and unloading cargo and people embarking and disembarking, ports have developed in areas with many industrial activities that are sources of noise. Moreover, in the last years, several ports have been expanded, becoming closer to residential areas. This is causing a constant increase in noise pollution for residents in those areas
Setting of on board noise sources in numerical simulation of airborne outdoor ship noise
No full textNowadays, noise pollution is more and more increasing owing to the growth of industrial production and road and rail traffic. Harbours are certainly ones of the most sensitive areas as, in the last decades, they have become sites for development of industrial activities and goods trades, with a following unavoidable increase in noise pollution. Ship is one of the noise source that most contributes to the overall noise pollution in harbour areas.
A recent European research project called BESST is aiming to improve knowledge about ship noise in order to propose proper actions to reduce noise pollution and new uniform criteria and limits for noise radiated to European harbours. Among the various aspects that the scientific community should examine, determination of a proper computational tool to predict outdoor noise generated by ships right in ship’s design phase is one of
the main things.
In the present study, carried out at the University of Trieste, an operative procedure for predicting ship’s outdoor noise in harbour is proposed. Procedure is outlined in all its steps from the pre to the post processing phase giving more emphasis to the noise sources setting within the numerical simulation. Effectiveness of the method has been proved by application to a case study
Confronto tra il metodo di Glaser e un modello globale di trasporto di calore e di massa in regime dinamico
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Autoclaved aerated concrete: Experimental evaluation of its thermal properties at high temperatures
No full textThis paper presents the results of experimental measurements of thermal conductivity and of volumetric specific heat, ρ Cp, carried out at high temperature on autoclaved aerated concrete (AAC) specimens at different densities. The Knowledge of the correlation of thermal conductivity and specific heat with temperature is of fundamental importance in the study of the mechanical behaviour of building materials in presence of ire. The numerical verifications of ire resistance of structures are often carried out using computer codes that solve differential equations of thermal exchanges. For this reason a proper Knowledge of the above thermal properties as a function of temperature is required. The measurement of thermal conductivity and thermal diffusivity has been carried out using a Hot Disk Thermal Constants Analyser equipment. The experimental environment suitable to achieve high temperatures consists of a special controlled temperature oven in which measurements are made with sensors enclosed in two layers of refractory material (mica) suitable for working with acceptable accuracy in a range of temperatures between 500-1000 K. The results are also compared with the directions on the material provided by national and international standards but we realized that the thermal conductivity values at high temperatures, suggested by the standard EN 12602, are significantly lower than those experimentally measured in this study and thus they are not precautionary checks for computational ire resistance. We propose to investigate on the source of the suggested data and ask a revision of the above mentioned standard
Optical manipulation of qubits by deep reinforcement learning
No full textQuantum compiling and qubit manipulations can be efficiently solved by using deep reinforcement learning algorithms. The advantages range from lower computational time to real-time programming We review examples such as STIRAP and single qubits operation
Trasporto di calore e di massa nei materiali da costruzione porosi: influenza delle condizioni al contorno sui fenomeni di condensaziobne
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