scholarly journals Developments in Electric and Green Marine Ships

2019 ◽  
Vol 2 (4) ◽  
pp. 34
Author(s):  
Agis G. Koumentakos
Keyword(s):  
Electric Propulsion ◽  
Alternative Fuels ◽  
State Of The Art ◽  
The State ◽  
Total Power ◽  
Small Contribution ◽  
Transitional Stage ◽  
Maritime Industry ◽  
Zero Emission

The maritime industry, among all other industries, is being forced to gradually reduce its emissions. Legislation is one of the tools applying this pressure, and from 1 January 2020, it focuses on the reduction of sulfur percentage in the heavy fuel oil (HFO)-powered vessels to 0.5%. In the beginning of this paper, the harmful environmental contribution of the naval sector is presented, along with the current legislation. The maritime industry is in a transitional stage, diverging from fossil fuels through alternative technologies and fuels, aiming to become over the long term a zero-emission industry. However, there are many implemented technologies, mostly of a mechanical nature, that already improve the efficiency of vessels and indirectly reduce their emissions. Such technologies include shaft generators (SGs), scrubbers, etc. The aim is for alternative fuels and technologies such as solar and wind to be implemented, too. Such technologies, when combined with the advantages of digitalization and automation, can further reduce emissions toward zero-emission vessels (ZEVs) through integrated systems. The present paper serves the purpose of a common point of gathering, addressing, and explaining the latest updates, previous achievements, and future targets of the maritime sector. The very nature of the subject—electric propulsion in the maritime sector—makes it very difficult to find sufficient and trustworthy data. There are two main reasons for this problem. The first one is that electric vehicles became commercial at a large scale (electric cars) very recently, and are still in a transitional stage. The second reason is that the maritime industry is very competitive; therefore, state-of-the-art technologies and data that give each company the lead are rarely published, and when they do, it happens very discreetly. In the quantitative part of the paper, where the photovoltaic (PV) and battery system calculations take place, there is no use of a specific model rather than a simplified approach. The purpose of the calculations is to show that with the present technologies, a purely solar-powered commercial vessel (such as RoRo, passenger, etc.) is technically impossible, and that there could be only a small contribution—of around 7%—to the electricity needs of a roll-on/roll-off (RoRo)-passenger ship. The state of the art finds a very short number of vessels that already use battery propulsion, but is expected to increase in the upcoming years. The present paper not only presents an overview of the state-of-the-art achievements in the electric propulsion of vessels, it also considers the exploitation of the continuous growth that the battery market is facing. As stated before, batteries are on the up, and this is due to the emerging need for energy storage in electricity grids that depend increasingly on renewable energy sources (RES). The paper makes a first consideration about the feasibility and possible benefits of implementing grid-like battery systems on-board vessels. In such a scenario, vessels would acquire significantly bigger energy capacity, allowing greater travel distances, a possible contribution of 44% of the vessel’s total power requirements (propulsion included), and a surplus as far as electricity requirements are concerned. There is also the more futuristic long-term scenario where Green Ports would charge vessels purely from RES dedicated to the port’s needs. The last part of the paper contains a qualitative assessment about the possible impacts that a battery-powered maritime industry could have.

scholarly journals A Multilayer CARU Framework to Obtain Probability Distribution for Paragraph-Based Sentiment Analysis

2021 ◽  
Vol 11 (23) ◽  
pp. 11344
Author(s):  
Wei Ke ◽  
Ka-Hou Chan
Keyword(s):  
Probability Distribution ◽  
Information Extraction ◽  
Sentiment Analysis ◽  
State Of The Art ◽  
Final Analysis ◽  
The State ◽  
Experimental Results ◽  
Content Adaptive

Paragraph-based datasets are hard to analyze by a simple RNN, because a long sequence always contains lengthy problems of long-term dependencies. In this work, we propose a Multilayer Content-Adaptive Recurrent Unit (CARU) network for paragraph information extraction. In addition, we present a type of CNN-based model as an extractor to explore and capture useful features in the hidden state, which represent the content of the entire paragraph. In particular, we introduce the Chebyshev pooling to connect to the end of the CNN-based extractor instead of using the maximum pooling. This can project the features into a probability distribution so as to provide an interpretable evaluation for the final analysis. Experimental results demonstrate the superiority of the proposed approach, being compared to the state-of-the-art models.

scholarly journals Learning from Interventions Using Hierarchical Policies for Safe Learning

2020 ◽  
Vol 34 (06) ◽  
pp. 10352-10360
Author(s):  
Jing Bi ◽  
Vikas Dhiman ◽  
Tianyou Xiao ◽  
Chenliang Xu
Keyword(s):  
Reaction Time ◽  
State Of The Art ◽  
The State ◽  
Policy Framework ◽  
Asymptotic Performance ◽  
Short Term ◽  
Learning From Demonstrations ◽  
Hierarchical Levels ◽  
Long Term Behavior

Learning from Demonstrations (LfD) via Behavior Cloning (BC) works well on multiple complex tasks. However, a limitation of the typical LfD approach is that it requires expert demonstrations for all scenarios, including those in which the algorithm is already well-trained. The recently proposed Learning from Interventions (LfI) overcomes this limitation by using an expert overseer. The expert overseer only intervenes when it suspects that an unsafe action is about to be taken. Although LfI significantly improves over LfD, the state-of-the-art LfI fails to account for delay caused by the expert's reaction time and only learns short-term behavior. We address these limitations by 1) interpolating the expert's interventions back in time, and 2) by splitting the policy into two hierarchical levels, one that generates sub-goals for the future and another that generates actions to reach those desired sub-goals. This sub-goal prediction forces the algorithm to learn long-term behavior while also being robust to the expert's reaction time. Our experiments show that LfI using sub-goals in a hierarchical policy framework trains faster and achieves better asymptotic performance than typical LfD.

scholarly journals A pilot for implementing environmental DNA (eDNA) based methods into environmental and biomonitoring

2021 ◽  
Vol 4 ◽  
Author(s):  
Tiina Laamanen ◽  
Veera Norros ◽  
Sanna Suikkanen ◽  
Mikko Tolkkinen ◽  
Kristiina Vuorio ◽  
...  
Keyword(s):  
Best Practices ◽  
Information Exchange ◽  
State Of The Art ◽  
Environmental Dna ◽  
Bulk Sample ◽  
The State ◽  
Molecular Techniques ◽  
Future Research ◽  
Dna Metabarcoding

Environmental DNA (eDNA) and other molecular based approaches are revolutionizing the field of biomonitoring. These approaches undergo rapid modifications, and it is crucial to develop the best practices by sharing the newest information and knowledge. In our ongoing project we: assess the state-of-the-art of eDNA methods at Finnish Environment Institute SYKE; identify concrete next steps towards the long-term aim of implementing eDNA methods into environmental and biomonitoring; promote information exchange on eDNA methods and advance future research efforts both within SYKE and with our national and international partners. assess the state-of-the-art of eDNA methods at Finnish Environment Institute SYKE; identify concrete next steps towards the long-term aim of implementing eDNA methods into environmental and biomonitoring; promote information exchange on eDNA methods and advance future research efforts both within SYKE and with our national and international partners. Scientific background Well-functioning and intact natural ecosystems are essential for human well-being, provide a variety of ecosystem services and contain a high diversity of organisms. However, human activities such as eutrophication, pollution, land-use or invasive species, are threatening the state and functioning of ecosystems from local to global scale (e.g. Benateau et al. 2019; Reid et al. 2018; Vörösmarty et al. 2010). New molecular techniques in the field and in the laboratory have enabled sampling and identification of much of terrestrial, marine and freshwater biodiversity. These include environmental DNA (eDNA, e.g. Valentini et al. 2016) and bulk-sample DNA metabarcoding approaches (e.g. Elbrecht et al. 2017) and targeted RNA-based methods (e.g. Mäki and Tiirola 2018). The eDNA technique uses DNA that is released from organisms into their environment, from which a signal of organisms’ presence in the system can be obtained. For example, in aquatic ecosystems, eDNA is typically extracted from sediment or filtered water samples (e.g. Deiner et al. 2016), and this approach is distinguished from bulk DNA metabarcoding, where organisms are directly identified from e.g. complete biological monitoring samples (e.g. Elbrecht et al. 2017). Despite the demonstrated potential of environmental and bulk-sample DNA metabarcoding approaches in recent years, there are still significant bottlenecks to their routine use that need to be addressed (e.g. Pawlowski et al. 2020). Methods and implementati on The project is divided into three work packages: WP1 Gathering existing knowledge, identifying knowledge gaps and proposing best practices, WP2 Roadmap to implementation and WP3 eDNA monitoring pilot. Please see more details in the Fig. 1

Self-healing organic coatings based on microcapsules – A patent-based review

2021 ◽  
Vol 04 ◽  
Author(s):  
Diego Moreira Schlemper ◽  
Sérgio Henrique Pezzin
Keyword(s):  
Corrosion Protection ◽  
State Of The Art ◽  
Review Article ◽  
The State ◽  
Organic Coatings ◽  
Self Healing ◽  
Future Challenges ◽  
The Matrix ◽  
Healing Agent

: Self-healing coatings are intended to increase long-term durability and reliability and can be enabled by the presence of microcapsules containing a self-healing agent capable of interacting with the matrix and regenerating the system. This review article provides an overview of the state-of-the-art, focusing on the patents published in the field of microcapsule-based self-healing organic coatings, since the early 2000’s. A discussion about coatings for corrosion protection and the different self-healing approaches and mechanisms are also addressed, as well as future challenges and expectations for this kind of coatings.

scholarly journals Documentary data and the study of the past droughts: an overview of the state of the art worldwide

2018 ◽  
Author(s):  
Rudolf Brázdil ◽  
Andrea Kiss ◽  
Jürg Luterbacher ◽  
David J. Nash ◽  
Ladislava Řezníčková
Keyword(s):  
Large Scale ◽  
State Of The Art ◽  
The State ◽  
Drought Indices ◽  
Documentary Evidence ◽  
Instrumental Observations ◽  
Spatio Temporal ◽  
Epigraphic Evidence ◽  
Administrative Evidence

Abstract. The use of documentary evidence to investigate past climatic trends and events has become a recognised approach in recent decades. This contribution presents the state of the art in its application to droughts. The range of documentary evidence is very wide, including: general annals, chronicles, and memoirs, diaries kept by missionaries, travellers and those specifically interested in the weather, the records kept by administrators tasked with keeping accounts and other financial and economic records, legal-administrative evidence, religious sources, letters, marketplace and shopkeepers' songs, newspapers and journals, pictographic evidence, chronograms, epigraphic evidence, early instrumental observations, society commentaries, compilations and books, and historical-climatological databases. These come from many parts of the world. This variety of documentary information is evaluated with respect to the reconstruction of hydroclimatic conditions (precipitation, drought frequency and drought indices). Documentary-based drought reconstructions are then addressed in terms of long-term spatio-temporal fluctuations, major drought events, relationships with external forcing and large-scale climate drivers, socio-economic impacts and human responses. Documentary-based drought series are also discussed from the viewpoint of spatio-temporal variability for certain continents, and their employment together with hydroclimate reconstructions from other proxies (in particular tree-rings) is discussed. Finally, conclusions are drawn and challenges for the future use of documentary evidence in the study of droughts are presented.

scholarly journals Perspectives and Development of Electrical Systems in More Electric Aircraft

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Ahmet Yigit Arabul ◽  
Emre Kurt ◽  
Fatma Keskin Arabul ◽  
İbrahim Senol ◽  
Martin Schrötter ◽  
...  
Keyword(s):  
Power Systems ◽  
Electric Propulsion ◽  
State Of The Art ◽  
Aircraft Design ◽  
The State ◽  
Total Change ◽  
Profound Change ◽  
Electrical Systems ◽  
Electric Aircraft ◽  
More Electric Aircraft

On-board electrical systems are the key components of each modern aircraft. They enable its safer, more comfortable, and environmentally friendlier operation. The strict regulations to reduce pollution and noise are produced by aircraft eventuated in projects like Clean Sky or ICAO Global Coalition for Sustainable Aviation. One solution to environmentally friendlier operation is the full electric propulsion of the aircraft, which enables the reduction of both noise and pollution. Such a concept requires a total change of all on-board power systems and enables the profound change in aircraft design. This paper presents the evolution of aircraft power systems into the so-called more electric aircraft (MEA) and discusses the state-of-the-art electrical systems. Furthermore, the concept of all-electric aircraft (AEA) is presented here.

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