• European Marine Science
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Electrification and digital tools are both on the rise. Digital tools can save time and resources, while for example hybrid and full electric marine vessels decrease operating costs and emissions in transport. These vessels require their power electronic devices to work perfectly in synchronization as a complete system, which requires careful parameterization of the equipment and control logic. The objective of this thesis is to create a simplified simulation model of a generic marine hybrid powertrain to be used in parameter testing. The minimum required parameters needed to parameterize the model to match a real-life vessel and a verification of the model's function are also needed. The simulation model was made with Matlab and Simulink from MathWorks. The modelled system's layout is based on multiple existing Danfoss Editron projects, as the model would need to be usable for different set-ups. Existing simulation models and their components were used for guidance and as building blocks. The model's logic and rules are based on Danfoss Editron's internal instructions, manuals, and knowledge. The final product is presented in sections. The simulation model contains genset models, an energy storage model, a load model, a power balance model, and a DC-link model. Input and output signals as well as relevant equations are given for each of these sections. Continuous testing was done throughout the development of the model, and the performance of the final version was verified by parameterizing it to match an existing vessel and comparing the model's output data to measured data. A list of minimum required parameters for setting up the model was constructed during the verification tests and these parameter lists are presented. Based on the relatively small errors between simulated and measured data, the model could be used in parameter and control logic testing in pre-commissioning. Further development could be done to include for example a PLC model, more precise diesel and battery models, more options for different control types, and more user interface functions. Maailma sähköistyy ja digitaaliset työkalut yleistyvät. Digitaalisilla työkaluilla voidaan säästää aikaa ja resursseja, kun taas esimerkiksi hybridi- ja täyssähkölaivat vähentävät käyttökustannuksia ja päästöjä liikenteessä. Tällaisissa laivoissa käytetyn tehoelektroniikan on muodostettava yhtenäisesti toimiva järjestelmä, mikä vaatii tarkkaa laitteiden ja ohjauslogiikan parametrisointia. Tämän työn tarkoituksena on tehdä yksinkertainen ja yleispätevä simulaatiomalli hybridilaivan sähköisestä voimansiirtojärjestelmästä parametritestaamista varten. Vähimmäisvaatimuksena olevat parametrit, joilla mallin saa parametrisoitua vastaamaan oikeaa laivaa, sekä mallin verifiointi vaaditaan myös. Simulaatiomalli toteutettiin MathWorksin Matlabilla ja Simulinkillä. Simuloidun järjestelmän rakenne perustuu useaan Danfoss Editronin todelliseen projektiin, koska mallin pitää olla sovellettavissa erilaisiin järjestelmiin. Olemassa olevia simulaatiomalleja ja niiden osia käytettiin työssä sekä suuntaohjeina että varsinaisina komponentteina. Mallin logiikka ja säännöt pohjautuvat Danfoss Editronin sisäisiin ohjeisiin, manuaaleihin ja tietoihin. Lopputulos esitellään osissa. Simulaatiossa on generaattori-, energiavarasto-, kuorma-, tehotasapaino- sekä DC-linkkimallit. Jokaiselle osiolle esitetään sisään- ja ulostulosignaalit sekä olennaiset yhtälöt. Mallia testattiin jatkuvasti sen kehityksen aikana ja lopullinen versio verifioitiin parametrisoimalla se vastaamaan olemassa olevaa laivaa ja vertaamalla mallin antamaa dataa mitattuun dataan. Mallin valmistelussa tarvitut olennaisimmat parametrit listattiin verifiointiprosessin aikana ja nämä listat esitellään työssä. Simuloidun ja mitatun datan suhteellisten pienten eroavaisuuksien perusteella tämän työn aikana rakennettu simulaatiomalli soveltuu kätettäväksi käyttöönottoa edeltävissä parametri- ja ohjauslogiikkatesteissä. Jatkokehitysvaiheissa malliin voitaisiin esimerkiksi lisätä PLC-malli, tarkemmat diesel- ja akkumallit, enemmän ohjauslogiikkavaihtoehtoja, sekä kehittää käyttöliittymää.

Tässä kandityössä tutkitaan polymeerikomposiittien käyttökohteita ja käyttöön johtaneita syitä veneteollisuudessa. Työssä on selvitetty veneteollisuuden erityisiä materiaaleihin liittyviä vaatimuksia, sekä polymeerikomposiittien soveltuvuutta veneteollisuuteen. Työstä selviää myös erilaisia polymeerikomposiittien kehityskohteita veneteollisuudessa. Tutkimus on kirjallisuuskatsaus, jonka tietolähteinä käytetään painettua kirjallisuutta, sekä julkisia internetistä löytyviä artikkeleita ja valmistajien kotisivuja. Tutkimuksessa tutkitaan pääasiassa alle 24-metrisiä veneitä, sillä sitä suurempia aluksia voidaan pitää jo laivoina. Tutkimuksessa selvisi, että polymeerikomposiitit ovat erittäin suosittu materiaali veneteollisuudessa, mutta polymeerikomposiiteilla on kuitenkin vielä kehitys tarpeita. Työn tuloksena löydettiin veneteollisuuteen sopivien polymeerikomposiittien tärkeitä ominaisuuksia, sekä käyttökohteita. This bachelor’s thesis investigates the applications of polymer composites and the reasons behind the use of polymer composites in the boat industry. The research explains what is required from materials in boat industry, and how polymer composites suite the boat industry applications. The work also reveals development needs for polymer composites in the boat industry. The study is a literature review in which printed literature as well as public articles and manufacturers' websites are used as sources. The study focuses on boats less than 24 long in length, as larger ones can already be considered ships. The study found that polymer composites are already a very popular material in the boat industry, but polymer composites still have development needs in the industry. As a result of this study, important properties, and applications for polymer composites in boat industry were found.

As part of the Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP), several climate modeling centers performed a coordinated pre-study experiment with interactive stratospheric aerosol models simulating the volcanic aerosol cloud from an eruption resembling the 1815 Mt. Tambora eruption (VolMIP-Tambora ISA ensemble). The pre-study provided the ancillary ability to assess intermodel diversity in the radiative forcing for a large stratospheric-injecting equatorial eruption when the volcanic aerosol cloud is simulated interactively. An initial analysis of the VolMIP-Tambora ISA ensemble showed large disparities between models in the stratospheric global mean aerosol optical depth (AOD). In this study, we now show that stratospheric global mean AOD differences among the participating models are primarily due to differences in aerosol size, which we track here by effective radius. We identify specific physical and chemical processes that are missing in some models and/or parameterized differently between models, which are together causing the differences in effective radius. In particular, our analysis indicates that interactively tracking hydroxyl radical (OH) chemistry following a large volcanic injection of sulfur dioxide (SO2) is an important factor in allowing for the timescale for sulfate formation to be properly simulated. In addition, depending on the timescale of sulfate formation, there can be a large difference in effective radius and subsequently AOD that results from whether the SO2 is injected in a single model grid cell near the location of the volcanic eruption, or whether it is injected as a longitudinally averaged band around the Earth.

This study presents simulations of Greenland surface melt for the Eemian interglacial period (∼130 000 to 115 000 years ago) derived from regional climate simulations with a coupled surface energy balance model. Surface melt is of high relevance due to its potential effect on ice core observations, e.g., lowering the preserved total air content (TAC) used to infer past surface elevation. An investigation of surface melt is particularly interesting for warm periods with high surface melt, such as the Eemian interglacial period. Furthermore, Eemian ice is the deepest and most compressed ice preserved on Greenland, resulting in our inability to identify melt layers visually. Therefore, simulating Eemian melt rates and associated melt layers is beneficial to improve the reconstruction of past surface elevation. Estimated TAC, based on simulated melt during the Eemian, could explain the lower TAC observations. The simulations show Eemian surface melt at all deep Greenland ice core locations and an average of up to ∼30 melt days per year at Dye-3, corresponding to more than 600 mm water equivalent (w.e.) of annual melt. For higher ice sheet locations, between 60 and 150 mmw.e.yr-1 on average are simulated. At the summit of Greenland, this yields a refreezing ratio of more than 25 % of the annual accumulation. As a consequence, high melt rates during warm periods should be considered when interpreting Greenland TAC fluctuations as surface elevation changes. In addition to estimating the influence of melt on past TAC in ice cores, the simulated surface melt could potentially be used to identify coring locations where Greenland ice is best preserved.

The data were collected from an experiment using phytoplankton cultures (Apocalathium malmogiense and Rhodomonas marina). The aim of the experiment was to study carbon cycling among phytoplankton and bacteria, and the effects on the dissolved organic matter (DOM) pool. Measured variables include phytoplankton and bacterial abundance, primary production, bacterial production and respiration, 14C-transfer from phytoplankton to DOM and bacteria, concentrations of particulate and dissolved organic carbon, nitrate, phosphate and chlorophyll a, and optical characteristics of dissolved organic matter. The experiment was conducted at Tvärminne Zoological Station, Hanko, Finland with non-axenic unialgal phytoplankton cultures and bacteria originating from the Baltic Sea. The experiment was conducted between Dec. 2017 and Apr. 2018. The experiment consisted of two parts, the DOM release experiment (part 1) and the DOM consumption experiment (part 2). Separate triplicate batch cultures of both phytoplankton species were grown for each experiment. In the DOM release experiment the cultures were grown for over 4 months and three day-long incubations (key point incubations, KPI's) were initiated on three occasions; the first KPI at early exponential growth phase and the second and third KPI's when the phytoplankton had grown more abundant. During each KPI and aliquot of the culture was inoculated with freshly collected sea water bacteria, and bacterial community composition was measured. This aliquot was then divided into two further aliquots; one was incubated with radioisotopes for productivity (primary and bacterial production) and 14C-flow analyses (production line) and one filtered through 0.8 µm for analysis of DOM optical properties. During the KPI's measurements were taken at 0, 4, 8 and 12 h. Nutrient concentrations (measured from non-filtered and 0.8 µm filtered samples) and concentration of dissolved organic carbon were measured only at 0 and 12 h. Concentrations of particulate organic carbon and nitrogen and chlorophyll a were measured only once for each KPI at the beginning of the incubation. In the DOM consumption experiments the cultures were grown to high abundance, after which the phytoplankton and most of the bacteria were filtered out. The filtrate was then inoculated with freshly collected sea water bacteria, after which it was incubated for 7 days. Bacterial abundance, production, respiration, and community composition, and concentration and optical properties of DOM were measured daily. The experimental design is explained in figure 1 of the associated publication.

Tämän diplomityön tarkoituksena on määrittää teknologiset vaihtoehdot lämpöenergian talteenotolle, varastoinnille ja hyödyntämiselle Itämeren alueen avustavalle jäänmurtajalle. Lämpöenergian talteenoton ja varastoinnin tarkoituksena on alentaa polttoaineen kulutusta, päästöjä ja käyttökustannuksia. Kansainvälisen merenkulun päästöjä tulee vähentää 50 % vuoden 2008 tasosta vuoteen 2050 mennessä. Päästötavoitteen saavuttaminen vaatii alusten energiatehokkuuden parantamista sekä vaihtoehtoisten polttoaineiden käyttöönottoa. Dieselmoottorin hyötysuhde on jo lähes 50 %. Suurin osa jäljelle jäävästä energiasta esiintyy lämpöenergiana pakokaasuissa ja jäähdytysvedessä. Tätä lämpöenergiaa voidaan ottaa talteen, varastoida ja hyödyntää aluksen sekä sen eri järjestelmien lämmittämiseen. Jäänmurtajan vaihtelevasta käyttöprofiilista johtuen talteen otettavan lämpöenergian ja sen kulutuksen suhde eivät useimmissa operointitapauksissa ole samanaikaisia. Työssä esitetään laskennallisesti jäänmurtajan lämpötase. Laskennan ja määritettyjen teknologisten vaihtoehtojen perusteella lämpöenergian talteenotto ja varastointi on kannattavaa. The meaning of this Master’s thesis is to evaluate the technologies for waste heat recovery, thermal energy storage and utilization for the assisting Baltic Sea area icebreaker. The meaning of waste heat recovery and thermal energy storage is to reduce fuel consumption, exhaust emissions and operational costs. The emissions from the international shipping should be reduced by at least 50 % by year 2050 compared to year 2008. In order to achieve the goal measures has to be taken. These measures are better energy efficiency and introduction of alternative fuels. The energy efficiency of a modern diesel engine is close to 50 %. Most of the remaining energy is in form of thermal energy in exhaust gases and cooling water. This thermal energy may be recovered, stored and utilized for the heating of the vessel and its systems. An icebreaker operates on varying engine loads and because of this the production and usage of thermal energy is not always concurrently. Based on the calculations in this thesis it is profitable to recover and store thermal energy onboard an icebreaker.

Coastal systems can act as filters for anthropogenic nutrient input into marine environments. Here, we assess the processes controlling the removal of phosphorus (P) and nitrogen (N) for four sites in the eutrophic Stockholm archipelago. Bottom water concentrations of oxygen (O2) and P are inversely correlated. This is attributed to the seasonal release of P from iron-oxide-bound (Fe-oxide-bound) P in surface sediments and from degrading organic matter. The abundant presence of sulfide in the pore water and its high upward flux towards the sediment surface (∼4 to 8 mmol m−2 d−1), linked to prior deposition of organic-rich sediments in a low-O2 setting (“legacy of hypoxia”), hinder the formation of a larger Fe-oxide-bound P pool in winter. This is most pronounced at sites where water column mixing is naturally relatively low and where low bottom water O2 concentrations prevail in summer. Burial rates of P are high at all sites (0.03–0.3 mol m−2 yr−1), a combined result of high sedimentation rates (0.5 to 3.5 cm yr−1) and high sedimentary P at depth (∼30 to 50 µmol g−1). Sedimentary P is dominated by Fe-bound P and organic P at the sediment surface and by organic P, authigenic Ca-P and detrital P at depth. Apart from one site in the inner archipelago, where a vivianite-type Fe(II)-P mineral is likely present at depth, there is little evidence for sink switching of organic or Fe-oxide-bound P to authigenic P minerals. Denitrification is the major benthic nitrate-reducing process at all sites (0.09 to 1.7 mmol m−2 d−1) with rates decreasing seaward from the inner to outer archipelago. Our results explain how sediments in this eutrophic coastal system can remove P through burial at a relatively high rate, regardless of whether the bottom waters are oxic or (frequently) hypoxic. Our results suggest that benthic N processes undergo annual cycles of removal and recycling in response to hypoxic conditions. Further nutrient load reductions are expected to contribute to the recovery of the eutrophic Stockholm archipelago from hypoxia. Based on the dominant pathways of P and N removal identified in this study, it is expected that the sediments will continue to remove part of the P and N loads.