On the Geometrical Non-Linearities of the Ship Load Expressions

In the structural analysis a fundamental rule is played by the internal forces and moments: they are the only variables on which the study for the primary level of the ship structural response is based, in accordance with beam theory. First of all, based on the usual decomposition of loads general expressions for the distributed still water, inertial and restoring loads have been revisited. Additionally, the influence of the non-linearity arising from the hull geometry on loads has been studied. Particular attention has been also given to the evaluation of loads due to the dynamic pressure in wave. Finally, two numerical examples have been carried out in order to verify the aforementioned influence on loads. The results obtained have been particularly discussed

Fuel saving and reduction of emissions in ports with cold ironing applications

The progress of economic globalization, the rapid growth of international trade and maritime transportation have played a significant role in providing international cargo and passenger transportation. Seaports all over the world are suffering from the problem of fuel consumption and exhaust gases coming by ships during their stopover in ports. In Italy, the emissions of the industrial and energy sectors have been reduced (almost 50% between 1998 and 2012), but the sulfur oxide (SOx ) from the maritime sector has almost doubled. The national and international maritime traffic is responsible for 80% of total emissions attributable to transportation. In this paper firstly we propose a method to compare the costs of various shore-side power sources connections with those obtained by use of auxiliary engines on board; two numerical examples have been developed. The results, in terms of costs and reduction of exhaust, have been particularly discussed

A Case Study of a Solid Oxide Fuel Cell Plant on Board a Cruise Ship

The work is a case study of a cruise ship supplied by liquefied natural gas (LNG) and equipped with a solid oxide fuel cell (SOFC). It is supposed that a 20 MW SOFC plant is installed on-board to supply hotel loads and assisting three dual-fuel (DF) diesel/LNG generator sets. LNG consumption and emissions are estimated both for the SOFC plant and DF generator sets. It results that the use of LNG-SOFC plant in comparison to DF generator sets allows to limit significantly the SOx, CO, NOx, PM emissions and to reduce the emission of CO2 by about 11%. A prediction of the weight and volume of the SOFC plant is conducted and a preliminary modification of the general arrangement of the cruise ship is suggested, according to the latest international rules. It results that the SOFC plant is heavier and occupies more volume on board than a DF gen-set; nevertheless, these features do not affect the floating and the stability of the cruise ship

Ship stability in wave: a proposal method for dynamic behaviour evaluation

Recent IMO activities are addressed to a renewal process about Intact Stability code. The new generation of stability criteria should be developed in order to be as close as possible to the real physics. The aim of this research work is to develop and validate a tool, intended for displacement vessels, capable to evaluate the ship response to wave actions and its effect on stability

Evaluation of the environmental impact of harbour activities: problem analisys and possible solutions

A relevant problem is a main subject of this work: the pollution in ports close to inhabited zones where, due to the contemporaneous presence of many cruise ships, the contents of noxious elements in the air are excessive and the quality of life risks to become unsustainable. The impact of the operations of cruise ships in port has been analysed together with the possible consequences of their impact on the human health and the rules that attempt to reduce the effects of the pollution on it. Some possible solutions were proposed; first of all, the so called “cold ironing” consisting in a connection between the electric system of the ship and a shore system providing the ship with the electric energy to be used onboard. The major characteristics of the cold ironing were analysed together with its main problems; among them, the need of integrate this practice in a more wide scene, combining it with the microgrids in order to not to solve the problem simply by moving the production of electric energy from one site to another

A Metric Framework for the Gamification of Web and Mobile GUI Testing

System testing through the Graphical User Interface (GUI) is a valuable form of Verification & Validation for modern applications, especially in graphically-intensive domains like web and mobile applications. However, the practice is often overlooked by developers mostly because of its costly nature and the absence of immediate feedback about the quality of test sequence. This paper describes a proposal for the Gamification of exploratory GUI testing. We define - in a tool and domain- agnostic way - the basic concepts, a set of metrics, a scoring scheme and visual feedbacks to enable a gamified approach to the practice; we finally discuss the potential implications and envision a roadmap for the evaluation of the approach

A Review on Tools, Mechanics, Benefits, and Challenges of Gamified Software Testing

Gamification is an established practice in Software Engineering to increase effectiveness and engagement in many practices. This manuscript provides a characterisation of the application of gamification to the Software Testing area. Such practice in fact reportedly suffers from low engagement by both personnel in industrial contexts and learners in educational contexts. Our goal is to identify the application areas and utilised gamified techniques and mechanics, the provided benefits and drawbacks, as well as the open challenges in the field. To this purpose, we conducted a Multivocal Literature Review to identify white and grey literature sources addressing gamified software testing. We analysed 73 contributions and summarised the most common gamified mechanics, concepts, tools and domains where they are mostly applied. We conclude that gamification in software testing is mostly applied to the test creation phase with simple white-box unit or mutation testing tools, and is mostly used to foster good behaviours by promoting the testers’ accomplishment. Key research areas and main challenges in the field are: careful design of tailored gamified mechanics for specific testing techniques; the need for technological improvements to enable crowdsourcing, cooperation, and concurrency; the necessity for empirical and large-scale evaluation of the benefits delivered by gamification mechanics

analysis of the micro voids fraction in structural steels and its evolution during plastic deformation until failure

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