With the current revolution in Shipping 4.0, a tremendous amount of data is accumulated during vessel operations.
Data quality (DQ) is becoming more and more important for the further digitalization and effective decision-making
in shipping industry. In this study, a practical DQ assessment method for raw data in vessel operations is proposed.
In this method, specific data categories and data dimensions are developed based on engineering practice and existing
literature. Concrete validation rules are then formed, which can be used to properly divide raw datasets. Afterwards,
a scoring method is used for the assessment of the data quality. Three levels, namely good, warning and alarm,
are adopted to reflect the final data quality. The root causes of bad data quality could be revealed once the internal
dependency among rules has been built, which will facilitate the further improvement of DQ in practice. A case study
based on the datasets from a Danish shipping company is conducted, where the DQ variation is monitored, assessed
and compared. The results indicate that the proposed method is effective to help shipping industry improve the quality
of raw data in practice. This innovation research can facilitate shipping industry to set a solid foundation at the early
stage of their digitalization journeys.
Scrubbers have gained importance in the maritime sector following recent tightening of the emission legislation regarding sulphur. In this work, a model framework based on an Eulerian-Eulerian multiphase model for a packed bed marine scrubber has been developed. The framework account for both dispersed droplets and a packed bed, where sub-models for interfacial forces and heat- and mass transfer are applied for the respective regions. Additionally, a chemistry model and boundary conditions for the nozzles injecting seawater into the scrubber are also implemented. The model framework is calibrated using data from an ocean-going vessel, where the model predictions were within 3% of the measured pressure loss while the discrepancy in the gas and liquid temperatures were between 0.5% and 3.5%. The sulphur concentration predicted by the model varies between − 24% and 25%. However, the concentrations were within 5 ppm of the measured values for all but a single data set.
Formålet med denne anden version af dette notat er stadig at få de vigtigste fakta om atomkraft i Danmark på bordet. I første version af notatet lagde vi op til en åben debat og inviterede til kommentarer og input. Dem har vi modtaget mange af. Det vil vi gerne takke for. Vi har brugt de mange kommentarer til at rette, forbedre, tilføje og uddybe, hvorfor vi nu kan fremlægge anden forbedrede og udbyggede udgave af notatet. Vi er selvfølgelig stadig åbne for at modtage kommentarer og inputs frem mod en version 3.
Nogle af de væsentligste ændringer i forhold til version 1 er:
Der er blevet spurgt til detaljerne i vores analyser og modelberegninger, da det for mange kan være svært at forstå, hvordan en fremtidig elforsyning baseret på vedvarende energi kan være stabil. Derfor har vi uddybet modelberegninger fra version 1 af notatet i to appendikser og tilføjet nye modelberegninger, som uddyber analyserne i forhold til det danske energisystems rolle i Europa. Desuden har vi tilføjet et helt afsnit om stabilitet, som forklarer, hvordan stabilitet og forsyningssikkerhed sikres i et vedvarende energisystem såvel som i et atomkraftsystem.
Der har været kritik af vores valg af eksempler på atomkraftværker, når vi har identificeret anlægsomkostninger og byggetider. Derfor har vi tilføjet flere til listen og uddybet diskussionen af hvilke omkostninger og byggetider, der er
relevante og aktuelle i en dansk sammenhæng. Et særskilt kritikpunkt har været valg af ’kapacitetsfaktor’. Kapacitetsfaktoren udtrykker, hvor meget et værk producerer igennem en periode sammenlignet med, hvor meget det maksimalt vil kunne producere, hvis det kørte ved fuld belastning (fuldlast) i hele perioden. Ved en kapacitetsfaktor på 100% vil værket køre fuldlast i hele perioden og ikke have ’udetider’, hvor værket ikke kan benyttes f.eks. ved direkte nedbrud, vedligehold eller regulering af driften for at følge behovsprofiler. Vi er her blevet kritiseret for at vælge 75% for atomkraftværker, og i stedet er der blevet peget på 85% som mere retvisende. Vi er også blevet kritiseret for ikke at indregne en eventuel udnyttelse af overskudsvarmen fra et atomkraftværk til fjernvarme, og der er blevet spurgt til, om vi har alle omkostninger til elnettet med. Som svar på disse kritikpunkter har vi foretaget flere beregninger med forskellige kapacitetsfaktorer for atomkraftværker samt analyser med og uden fjernvarmeudnyttelse. Hermed kan man klart se betydningen af disse valg af forudsætninger.
Kilden for vores valg af 75% er Det Internationale Energiagenturs World Energy Outlook, hvor de forudser, at atomkraft i 2050 i det Europæiske energisystem vil have en kapacitetsfaktor mellem 70% og 80%. 85% er teknisk muligt, men vælges typisk når atomkraft ikke indgår i sammenhæng med et energisystem med vedvarende energi.
For at styrke gyldigheden af vores beregninger har vi desuden tilføjet nye analyser af Danmark i en Europæisk sammenhæng, hvor vores beregningsmodeller både optimerer på investeringer i produktionskapacitet og på transmissionsledninger.
Disse ekstraanalyser ændrer dog ikke på den centrale hovedkonklusion: At et dansk energisystem med atomkraft er dyrere end et med vind og sol, og at atomkraft tager længere tid at opføre end vind- og solanlæg.
Endelig har der blandt nogle været en forvirring om, hvem vi er, og hvad vores faglighed er i forhold til atomkraftdebatten sammenlignet med forskere, som har en mere specialiseret baggrund i kernefysik eller lignende. Vi er en bred sammensætning af ingeniører, fysikere og økonomer. Vores fælles faglighed er koncentreret om energisystemanalyse, og vores forskningsområde er at analysere, hvordan vi på energiområdet bedst og billigst kan gennemføre den grønne omstilling og hurtigst muligt opnå et CO2-neutralt samfund. Vi er således ikke kun specialister i en enkelt teknologi. Vi er først og fremmest specialister i, hvordan teknologierne spiller sammen, så vi kan finde de bedste løsninger og
optimere det samlede energisystem.
Det er vores vurdering, at det netop er den faglighed og de forskningskompetencer, der er brug for, når konsekvenserne af at investere i atomkraft i Danmark skal sammenlignes med ikke at gøre det. Når trafikforhold skal udvikles og optimeres, er det også trafikforskerens kompetence, der efterspørges, og ikke ekspertise i f.eks. forbrændingsmotorteknologien.
Samlet set er rapporten inddelt i fire kapitler, der fokuserer på forskellige pointer. I kapitel 1 sammenlignes omkostningerne ved at producere en enhed (MWh) el fra henholdsvis atomkraft, sol og vind uafhængigt af resten af energisystemet;
Kapitel 2 har et fokus på de samme teknologier, men hvor de er i drift i energisystemet, og dermed kan betydningen af forskelle i produktionsmønstre fra vedvarende energi og atomkraft kvantificeres. Kapitel 3 fokuserer på den del af energisystemanalyserne, der omhandler forsyningssikkerhed og stabilitet. I kapitel 4 diskuterer vi bygge- og planlægningstider på atomkraft.
Despite the relatively rich literature on the omnipresence of microplastics in marine environments, the current status and ecological impacts of microplastics on global Marine Protected Areas (MPAs) are still unknown. Their ubiquitous occurrence, increasing volume, and ecotoxicological effects have made microplastic an emerging marine pollutant. Given the critical conservation roles of MPAs that aim to protect vulnerable marine species, biodiversity, and resources, it is essential to have a comprehensive overview of the occurrence, abundance, distribution, and characteristics of microplastics in MPAs including their buffer zones. Here, extensive data were collected and screened based on 1565 peer-reviewed literature from 2017 to 2020, and a GIS-based approach was applied to improve the outcomes by considering boundary limits. Microplastics in seawater samples were verified within the boundaries of 52 MPAs; after including the buffer zones, 1/3 more (68 MPAs) were identified as contaminated by microplastics. A large range of microplastic levels in MPAs was summarized based on water volume (0–809,000 items/m 3) or surface water area (21.3–1,650,000,000 items/km 2), which was likely due to discrepancy in sampling and analytical methods. Fragment was the most frequently observed shape and fiber was the most abundant shape. PE and PP were the most common and also most abundant polymer types. Overall, 2/3 of available data reported that seawater microplastic levels in MPAs were higher than 12,429 items/km 2, indicating that global MPAs alone cannot protect against microplastic pollution. The current limitations and future directions were also discussed toward the post-2020 Global Biodiversity Framework goals.
This work evaluates the hydrodynamic performance of an oscillating water column wave energy converter, with a focus on comparing conventional two-way energy capture to one-way energy capture where only the up- or down-stroke is used drive the turbine. Small-scale model test experiments are performed, and numerical calculations are made using weakly-nonlinear potential flow theory. The air turbine is represented experimentally by an orifice plate with a flow area equal to about 1% of the internal-chamber water-plane area. One-way energy capture by the experimental model is realized by incorporating a passive, low-inertia, non-return valve which vents the air inside the chamber on one half-cycle of the internal water-column oscillation. In the numerical calculations, there is little difference between the two venting configurations, due to the simplified weakly non-linear model. However, the experimental results show that up-stroke venting generally yields a higher power absorption than down-stroke venting and the two-way energy capture generally yields a higher power absorption compared to the one-way energy capture. The calculations agree well with the experiments for two-way absorption, but substantially over-predict the absorbed power in the one-way configuration. This is mainly attributed to the imperfect venting system in the physical model, but further tests and/or CFD calculations are needed to confirm this conclusion.
The approach documented in this paper employs system identification (SI), or data-based modelling, techniques as an alternative to model determination from first principles for modelling a vented oscillating water column wave energy converter, using real wave tank data gathered at Danmarks Tekniske Universitet. In SI, the parameters of the model are obtained from the experimental input/output data by minimizing a cost function, related to model fidelity. The main advantage of SI is its simplicity, as well as its potential validity range, where the dynamic model is valid over the full range for which the identification data was recorded. Furthermore, SI models are somewhat flexible, since they can be solely based on data (black-box models), or else can incorporate some physics-based information (grey-box models). However, a suitable excitation signal is of primary importance for the parametric model to be representative over a wide range of operating conditions.
The “Initial IMO Strategy” was adopted in the 72nd session of the Marine Environment Protection Committee (MEPC 72) of the International Maritime Organization (IMO) in April 2018. It has set, among other things, ambitious targets to reduce greenhouse gas (GHG) emissions from ships, and purports to express a strong political will to phase them out as soon as possible. The most ambitious of these targets is to reduce GHG emissions by 2050 at least 50% vis-à-vis 2008 levels, and there is also an intermediate target to reduce CO2 emissions per transport work by 2030 at least 40%, again vis-à-vis 2008 levels. More than three years since the adoption of the Initial IMO Strategy, this chapter takes stock at the status of shipping decarbonisation and attempts to assess prospects for the future. Obstacles towards achieving the IMO targets are identified and discussed.
This article examines the theoretical and practical implications of artificial intelligence (AI) integration in supply chain management (SCM). AI has developed dramatically in recent years, embodied by the newest generation of large language models (LLM) that exhibit human-like capabilities in various domains. However, SCM as a discipline seems unprepared for this potential revolution, as existing perspectives do not capture the potential for disruption offered by AI tools. Moreover, AI integration in SCM is not only a technical but also a social process, influenced by human sensemaking and interpretation of AI systems. This article offers a novel theoretical lens called the AI Integration (AII) framework, which considers two key dimensions: the level of AI integration across the supply chain and the role of AI in decision-making. It also incorporates human meaning-making as an overlaying factor that shapes AI integration and disruption dynamics. The article demonstrates that different ways of integrating AI will lead to different kinds of disruptions, both in theory and practice. It also discusses the implications of AI integration for SCM theorizing and practice, highlighting the need for cross-disciplinary collaboration and sociotechnical perspectives.
This article builds on rich empirical data following our unexpected discovery of a local practice to circumvent a stressful
and counterproductive work environment due to distrust at the Port of Tema in Ghana. Using theoretical work on networks,
trust, and humor, as well as extensive ethnographic feldwork, we found that the humorous atmosphere at the regularly
held physical berthing meetings fosters a sense of community, which enables competing professions, private companies,
and public institutions to manage their mutual distrust. In an environment where trust among competitors is unrealistic, we
argue that the objective of the performance of humor and transparency at the physical berthing meetings is the management
of distrust rather than the creation of trust. The meetings have, gradually, grown to serve as a pragmatic local stakeholder
adaptation to the challenges posed by universally perceived politicized, opaque, and corrupt business practices at the Port
of Tema and beyond. In conclusion, we posit that our empirical fndings allow us to identify the potential of and gaps in
theories about trust and humor in understanding the dynamics of coping strategies among competitors in business settings
that are characterized by unethical practices.
Design
Our data set, collected via surveys from top managers and project managers involved in 86 NPD projects in 85 firms, is analyzed using PLS structural equation modeling.
Purpose
This study examines how technical drivers as well as social drivers influence organic communication and top management involvement (TMI) in new product development (NPD) projects. Technical drivers are strategic importance and product innovativeness and social drivers are intrinsic and extrinsic relevance. Organic communication is defined as continuous, bi-directional, and informal communication between top management and the NPD teams. Further, arguing that TMI must be studied as multi-faceted construct, TMI is conceptualized to occur as guidance, active motivation, providing resources, and creating a tolerant climate. Subsequently, the effect of TMI and organic communication on NPD performance is investigated.
Findings
We show that the strategic importance of the project has a positive influence on TMI through active motivation, providing resources, and creating a tolerant climate for innovation, but does not have an effect on guidance. Results also show that active motivation and organic communication improve budget and schedule adherence, whereas providing guidance and stimulating a tolerant climate have detrimental effects. In summary, our results show that only active motivation enhances all types of performance while stimulating a tolerant climate appears to have the opposite effect. The results revealed that organic communication between top management and the NPD team has a strong positive effect on all elements of TMI (providing guidance, actively motivating the NPD team, providing resources, and creating a tolerant climate). In other words, when top management communicates with the NPD team throughout the project in an informal way and listens to the team in addition to engaging in a one-way communication, they are more likely to be seen by the team as being deeply involved in the project.