• European Marine Science
• Other research productsclose
• Open Access close
• FI close
• CH close
• European Marine Science close

Temperature and heating-induced temperature were measured along a chain of thermistors. Digital Thermistor Chain DTC16 is an autonomous instrument that was installed on drifting sea ice in the Arctic Ocean during the MOSAiC expedition on 7 November 2019. The thermistor chain was 4.16 m long and included sensors with a regular spacing of 2 cm. The resulting time series describes the evolution of temperature during the heating cycle of 20 s and after the heating cycle during the following 40 s as a function of geographic position (GPS), depth, and time between 7 November 2019 and 27 April 2020 in sample intervals of 6 hours. It also contains manually estimated position of air-snow, snow-ice, and ice-water interfaces. The DTC was installed in deformed second-year ice next to the HSVA stress panels close to RV Polarstern.

We present an age model for the 651 m deep Skytrain Ice Rise ice core (79°44.5'S, 78°32.7'W). The top 2000 years have previously been dated using age markers interpolated through annual layer counting. Below this, we align the Skytrain core to the AICC2012 age model using tie points in the ice and air phase, and apply the Paleochrono program to obtain the best fit to the tie points and glaciological constraints. In the gas phase, ties are made using methane and, in critical sections, δ18Oair; in the ice phase ties are through 10Be across the Laschamps Event, and through ice chemistry related to long-range dust transport and deposition. This strategy provides a good outcome to about 108 ka (~605 m). Beyond that there are signs of flow disturbance, with a section of ice probably repeated. Nonetheless values of CH4 and δ18Oair confirm that part of the last interglacial (LIG), from about 117-126 ka (617-628 m), is present and in chronological order. Below this there are clear signs of stratigraphic disturbance, with rapid oscillation of values in both the ice and gas phase at the base of the LIG section. Based on methane values, the warmest part of the LIG and the coldest part of the penultimate glacial are missing from our record. Ice below 631 m appears to be of age >150 ka.

Micropaleontological (coccolith, planktonic foraminifera) and geochemical (CaCO3, CaXRF, δ18O N. pachyderma, δ13C N. pachyderma) analyses from sediment core MD04-2718 retrieved from the Subantarctic zone (SAZ) of the Indian Southern Ocean covering the time interval from Marine Isotope Stage (MIS) 12 to MIS 10 (440,000– 360,000 years). Coccolith abundances and masses were performed using SYRACO software at Geoscience Paris-Saclay Laboratory (GEOPS). CaCO3 percentages were also measured at GEOPS. Foraminifera abundances and masses and stable oxygen and carbon isotopes were performed at Laboratoire des Sciences du Climat et de l'Environnement (LSCE). SST were calculated using two methods : the Modern Analogue Technique (Haddam et al., 2016) and the percentage of N. pachyderma s. (Govin et al., 2009). CaXRF measurements were performed at ETH, Zurich. These approaches allowed to decipher the variations in Carbonate Counter Pump and upwelling strength in the Indian Sector of the Southern Ocean between MIS 12 and MIS 10, including the Termination V and interglacial MIS 11.

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.

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.