DETERMINATION OF AN OPTIMAL FLEET FOR A CNG TRANSPORTATION SCENARIO IN THE MEDITERRANEAN SEA

For the natural gas transportation, several technologies can be applied, having different effectiveness and costs depending on the analysed case. The Mediterranean Sea is presenting a typical scenario where compressed natural gas (CNG) transportation is particularly attractive compared to liquefied natural gas (LNG) and pipelines, not only for stranded gas shipping but also for transportations cases where CNG is usually representing the most economically convenient solution. Approaching the design of a CNG ship is not an easy task, since the pressure vessel (PV) technology is strongly influencing the ship layout and hull form. Here an enhanced conceptual design method is adopted; taking into account the economic-financial issues together with logistics, in order to determine the best fleet composition selecting the best ships for the selected scenario. The ships composing the fleet are supposed to load/offload the natural gas on buoys; hence, dynamic positioning (DP) will also be considered as an attribute in the evaluation of alternative designs. As final outcome of the enhanced concept design process it will be possible to speed up drawing of the preliminary lines plan and general arrangement plan of the sister ships composing the fleet

The use of Bluetooth Beacons in Maritime Emergencies Mobile safety and security - DigLogs pilot project by University of Trieste

The aim of this paper is to research and describe how the use of mobile technologies can help in reducing the time required for the ship evacuation and abandonment procedures, as it was identified within the scope of 2014 - 2020 Interreg V-A Italy - Croatia CBC Programme \u201cDigitalising Logistics processes - DIGLOGS\u201d project. Furthermore, main findings and opportunities for proving technical feasibility will be identified and presented along with a carefully selected and envisaged test scenario chosen to compare the standard evacuation time with the one related to the adoption of the mobile technologies, the final goal being the streamlined evacuation procedures, and the increase of the ship's security and target group stakeholders' satisfaction

Feasibility Study of a DC Hybrid-Electric Catamaran for River Navigation

The sustainable growth is becoming every day more present and even mandatory in the framework of global decarbonization and Green House Gases (GHG) reduction. In such a context, electric powering offers important advantages while offering reliable and greener solutions for private-public urban transport. By considering this scenario, in this paper, an electric catamaran equipped with a DC hybrid module is proposed as effective in passenger transport along the Po river, in the Turin urban environment. The study encompasses many challenging aspects, which, in the end, improve the overall ship performance. For instance, the vessel shall be suitable for a quick hauling to the land in case of emergency with a crane truck. Secondly, the DC voltage distribution must provide safe power delivery by maintaining low weights. In this paper, the design is presented, along with the scenario constraints that have defined the peculiarities and addressed the technical choices

Thermoplastic Materials for the Metal Replacement of Non-Structural Components in Marine Engines

Metal replacements for automotive and aerospace components are already a consolidated reality, in light of the advantages offered by fibre-reinforced polymers, consisting of reduced costs, weight, and environmental impact. As a result, engineering has been studying the possibility of replacing currently used metallic alloys with alternative materials, such as thermoplastic fibre-reinforced polymers, in the manufacturing of non-structural sections of marine engines. Given the peculiar characteristics of the working environment of such parts, i.e., ship engine spaces, and the strict requirements regarding safety, the selection of the polymer must be properly performed through a tailored material design process. Consequently, the redesign of the components must be carried out with the aim of exploiting the best of the materials’ properties while ensuring the correct resistance and simplifying installation operations. In this framework, finite element simulations may represent a suitable approach to validate the conformity of the proposed material and design. In this paper, this methodology is applied to a camshaft cover of a four-stroke marine engine, currently made of aluminium alloy. A 30% wt GFs/PA6,6 was identified as the most promising material and the novel plastic cover proved to guarantee the correct resistance while ensuring an important reduction in weight, processing costs, and required energy

Biomimetic antimicrobial cloak by graphene-oxide agar hydrogel

Antibacterial surfaces have an enormous economic and social impact on the worldwide technological fight against diseases. However, bacteria develop resistance and coatings are often not uniform and not stable in time. The challenge is finding an antibacterial coating that is biocompatible, cost-effective, not toxic, and spreadable over large and irregular surfaces. Here we demonstrate an antibacterial cloak by laser printing of graphene oxide hydrogels mimicking the Cancer Pagurus carapace. We observe up to 90% reduction of bacteria cells. This cloak exploits natural surface patterns evolved to resist to microorganisms infection, and the antimicrobial efficacy of graphene oxide. Cell integrity analysis by scanning electron microscopy and nucleic acids release show bacteriostatic and bactericidal effect. Nucleic acids release demonstrates microorganism cutting, and microscopy reveals cells wrapped by the laser treated gel. A theoretical active matter model confirms our findings. The employment of biomimetic graphene oxide gels opens unique possibilities to decrease infections in biomedical applications and chirurgical equipment; our antibiotic-free approach, based on the geometric reduction of microbial adhesion and the mechanical action of Graphene Oxide sheets, is potentially not affected by bacterial resistance

Procjena posljedica oštećenja broda brzom simulacijom naplavljivanja odjeljaka : doktorska disertacija

Na temelju signala senzora naplavljivanja u posljednje se vrijeme simulira tijek naplavljivanja kod hitnih slučajeva na brodu, a sve sa ciljem stvaranja podrške pri donošenju odluka odgovornih članova posade. Da bi simulacija bila učinkovita, ista mora biti dovoljno točna, ali i dovoljno brza bez značajnijih računalnih zahtjeva. Nova matematička formulacija temeljena na linearizaciji jednadžbi modela naplavljivanja može poboljšati oba ova sukobljena zahtjeva. Na taj se način predložena metoda znatno lakše može primijeniti kada je vrijeme izračuna ograničeno ili kada se mora provesti velik broj simulacija naplavljivanja. Osim toga, baze podataka koje sadrže rezultate simulacija naplavljivanja mogu se uz algoritme strojnog učenja adekvatno koristiti za procjenu posljedica scenarija štete (konačni ishod, vrijeme naplavljivanja odjeljaka) samo na temelju vremenskog zapisa položaja i orijentacije plutajućeg broda (poprečni nagib broda, trim i uron). Predložena metoda može biti osnova za novu generaciju sustava za donošenje odluka na brodu, koji ne zahtijevaju ugradnju senzora naplavljivanja, što pak omogućuje jeftinu nadogradnju postojećih brodova.Recently, progressive flooding simulations have been applied onboard to support decisions during emergencies based on the outcomes of flooding sensors. To this end, both simulation accuracy and low computational effort are essential. A new mathematical formulation based on governing equations’ linearization can improve both these conflicting requirements, being more easily applied when calculation time is limited or a large number of flooding simulation has to be carried out. Besides, databases of flooding simulations together with machine learning algorithms can be exploited to assess the consequences of a damage scenario (final fate, flooded compartments time-to-flood) based only on the time evolution of the ship floating position (heel, trim and sinkage). The proposed method can be the base for a new generation of onboard decision support systems, which does not require the installation of flooding sensors, enabling cheap retrofit on most of the existing fleet

Procjena posljedica oštećenja broda brzom simulacijom naplavljivanja odjeljaka : doktorska disertacija

Na temelju signala senzora naplavljivanja u posljednje se vrijeme simulira tijek naplavljivanja kod hitnih slučajeva na brodu, a sve sa ciljem stvaranja podrške pri donošenju odluka odgovornih članova posade. Da bi simulacija bila učinkovita, ista mora biti dovoljno točna, ali i dovoljno brza bez značajnijih računalnih zahtjeva. Nova matematička formulacija temeljena na linearizaciji jednadžbi modela naplavljivanja može poboljšati oba ova sukobljena zahtjeva. Na taj se način predložena metoda znatno lakše može primijeniti kada je vrijeme izračuna ograničeno ili kada se mora provesti velik broj simulacija naplavljivanja. Osim toga, baze podataka koje sadrže rezultate simulacija naplavljivanja mogu se uz algoritme strojnog učenja adekvatno koristiti za procjenu posljedica scenarija štete (konačni ishod, vrijeme naplavljivanja odjeljaka) samo na temelju vremenskog zapisa položaja i orijentacije plutajućeg broda (poprečni nagib broda, trim i uron). Predložena metoda može biti osnova za novu generaciju sustava za donošenje odluka na brodu, koji ne zahtijevaju ugradnju senzora naplavljivanja, što pak omogućuje jeftinu nadogradnju postojećih brodova.Recently, progressive flooding simulations have been applied onboard to support decisions during emergencies based on the outcomes of flooding sensors. To this end, both simulation accuracy and low computational effort are essential. A new mathematical formulation based on governing equations’ linearization can improve both these conflicting requirements, being more easily applied when calculation time is limited or a large number of flooding simulation has to be carried out. Besides, databases of flooding simulations together with machine learning algorithms can be exploited to assess the consequences of a damage scenario (final fate, flooded compartments time-to-flood) based only on the time evolution of the ship floating position (heel, trim and sinkage). The proposed method can be the base for a new generation of onboard decision support systems, which does not require the installation of flooding sensors, enabling cheap retrofit on most of the existing fleet

Bulkheads’ Position Optimisation in the Concept Design of Ships under Deterministic Rules

The position of the transverse bulkheads is the most important aspect in determining the internal subdivision of the ship and has a strong impact on the general arrangement, weight distribution and capacity of the ship. Nowadays, deterministic rules still apply to various types of ships such as gas carriers, naval ships, icebreakers, etc. For these vessels a new floodable length can be defined as the extent of the ship that can be flooded, still assuring compliance with the damage stability criteria. The main objective of this paper is using the floodable lengths to optimize the position of bulkheads. The proposed methodology maximises the margin between the floodable length and the actual flooded length, which consists of two lost contiguous compartments. This method, applicable in the framework of multi-attribute decision-making techniques for ship concept design, allows identification of the minimum number of bulkheads a ship requires, quantification, and maximisation of the safety margin for compliance with deterministic damage stability criteria. This margin ensures maximum flexibility for changes that may be required in the next design phases. The proposed method, based on a multi-stage optimization, is tested on a compressed natural gas carrier to define the minimum number and position of the transverse bulkheads dividing the cargo holds

A new calculation technique for onboard progressive flooding simulation

During a flooding emergency, the master has to take hard decisions with serious impact on passengers and crew safety. A fast and reliable time domain simulation of the progressive flooding process can significantly aid the master in choosing the right counteractions immediately after the damage occurrence. In last decades many methods to simulate progressive flooding have been developed with increasing precision, but most of them require too much computational effort being not suitable for a direct onboard application. This paper presents a novel quasi-static simulation technique capable to provide accurate results in a reasonable calculation time. The analytical solution of the linearised system of governing differential equations allows to extend the time step over the intrinsic limits of numerical integration methods without affecting accuracy. The approach has been compared with numerical integration of non-linear system of equations and a recent pressure correction technique on a box-barge test case available in the literature

A Study on Ports’ Emissions in the Adriatic Sea

Environmental sustainability and energy efficiency are some of the most challenging objectives to be pursued in port areas. In this context, the SUSPORT project aims to provide its contribution, affecting the Adriatic area. In the initial phase, before applying new technologies/solutions to enhance port sustainability, the baseline status shall be assessed in order to evaluate the impact of tested measures. To this end, a review of the peculiarities of the main ports of the Adriatic Sea (Italian and Croatian), including the evaluation of their carbon footprint should be carried out. The present work reports the results of this phase, focusing on the main statistics of the involved ports and their greenhouse gases inventory at an aggregated level