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Abstract Environmental concern and tighter public regulations have created new pressures to reduce effluent loading from kraft pulp bleaching during the past decades. This trend has forced both pulp mills and the related engineering industries to develop and optimise equipment for the pulping processes which fulfils these demands. New pulp washers and washing systems connected with the introduction of new oxygen-based reagents have in particular provided considerably improved tools for reusing process water and thereby essentially reducing effluent discharge or even allowing the implementation of a totally closed water circulation system in kraft pulp bleaching. This study was performed mainly on a laboratory scale at the University of Oulu, but some pilot-scale tests were also performed to confirm the findings of the laboratory-scale evaporation test. Another aim of the pilot-scale tests was to produce enough concentrate for further processing. Conditions were strictly controlled in all the experiments in order to ensure that conclusions could be reached regarding the phenomena examined. The results reported here indicate that the amounts of transition metal ions such as iron, copper or manganese in the process water or water to be recirculated should be kept as low as possible during chlorine dioxide or peracetic acid bleaching, as even a small amount (<<5 ppm) markedly reduced pulp quality and increased reagent consumption. The results also show that evaporation can be used as a method for purifying acidic effluent from both chlorine dioxide and peracetic acid bleaching, and that the resulting condensates were free of transition metals and clean enough for reuse in both bleaching processes. The purity of the condensates was further improved by neutralising the feed pH of the acidic effluents from the bleach plant before evaporation. The results also indicate that the chloride ions in the concentrate arising from evaporation of the acidic effluent from chlorine dioxide bleaching can be removed by a combined acidification/re-evaporation system.

The naturally occurring isotopes 231Pa and 230Th are used as tracers of marine biogeochemical processes. They are both produced from the radioactive decay of their uniformly distributed uranium parents (235U and 234U) in seawater. After production, 231Pa and 230Th are removed by adsorption onto settling particles (scavenging) and subsequently buried in marine sediments. 230Th is more particle reactive compared to 231Pa. Consequently, 230Th will be removed from the open ocean by adsorption onto settling particles, while 231Pa tend to be laterally transported by currents and removed by scavenging in areas of high particle flux (e.g. ocean margins). The primordial 232Th indicates lithogenic supply via rivers and resuspension of sediments, which provides additional information about processes involved in the cycling of particle reactive elements in the ocean. The preferential deposition of particle reactive elements at ocean margins (boundary scavenging) has important implications for our understanding of the distribution and dispersion of micronutrients (e.g. iron) and pollutants in the ocean. It is therefore valuable to understand the nature of boundary scavenging processes in order to evaluate the relative contribution of circulation and scavenging behaviors.The major characteristics of thermohaline circulation in the Mediterranean are well known and have been studied for decades. This sea is an almost land-locked area, where limited water-exchange with the Atlantic Ocean only occurs through the Strait of Gibraltar. Therefore, this marginal sea is often referred to as a “miniature ocean” suitable as a “laboratory” for marine environmental research. In this licentiate thesis, distributions of 231Pa, 230Th and 232Th in seawater and marine particles collected during the GEOTRACES MedSeA-GA04-S cruise in 2013 are presented. Observed nuclide distributions indicate the impact of deep water formation processes, where observed differences can be linked to the type of deep water formation process that occurs in respective basin. Essentially all in-situ produced 230Th is buried in Mediterranean Sea sediments. Despite lower affinity of 231Pa for marine particles, most 231Pa is also scavenged and deposited in Mediterranean Sea sediments. The efficient scavenging of 231Pa produces a relatively low fractionation between 231Pa and 230Th in terms of the fractionation factor FTh/Pa. This licentiate thesis presents a summary of the methods used for the analysis of 231Pa and Th-isotopes with details on the exchange chromatography method and the treatment of mass spectrometric data. The study of 231Pa, 230Th and 232Th in the Mediterranean Sea has important implications for our understanding of processes that control their water column distributions and how their behavior can be utilized to trace chemical flux in modern and past ocean environments. / GEOTRACES / MeDSeA

Coastal regions provide a lot of resources and benefits for all the humankind. For economic growth, these resources are needed. On the other hand, coastal resources should be maintained and preserved in some limits. Sustainable development is aimed to set a balance between economic growth and preserving the nature. Determination of the yacht carrying capacity is a major step for sustainable development. In this thesis study wind-induced water circulation in semi-enclosed basins are carried out in order to reach the yacht carrying capacity for Fethiye Bay. Hydrodynamics of bays is very complex, mainly affected by wind and wave climate and sea bottom topography. The sea bed profiles at the bay changes under winter and summer storms of different speeds and directions. This case study will be carried out with the developed methodology. The present structure of Fethiye Bay will be analyzed and necessary measurements will be proceeded. Moreover, two more cases will be studied besides the present conditions. Circulation models will be applied to the study case according to reached data. For this purpose, Finite Volume Coastal Ocean Model (FVCOM) numerical model will be used.

We are at a time when energy efficiency and the reduction in the use of non-renewable energy is an important objective in all aspects and will continue to be so, therefore it is necessary to try to reduce energy and heat losses in the systems used in homes and, in particular, in the domestic hot water (DHW) system. This study aims to find out the advantages and disadvantages of an innovative pipe-in-pipe (PIP) system for DHW circulation with respect to the conventional system of two separate pipes. Previous studies have shown that DHW circulation is indeed an important point of energy losses in the home and that it is possible to reduce these losses by using the innovative system under study. The properties and coefficients defining the heat transfer system have been obtained for both the traditional and innovative systems by using empirical equations and iterative processes, indicating a 32% reduction in heat losses in favour of the pipe-in-pipe system. However, this result has been obtained in a kind of case study, using some simplifying assumptions, needed to accomplish to work within limited time. So the result could vary if a somewhat different system is studied, which is why it is necessary to carry out further studies and research on this subject in order optimize DHW systems in buildings.

Recent cooperative efforts between the University of Central Florida, the Florida Department of Environmental Protection, and the South Florida Water Management District explore the development of a two-dimensional, depth-integrated tidal model for the Loxahatchee River estuary (Southeastern Florida). Employing a large-domain approach (i.e., the Western North Atlantic Tidal model domain), two-dimensional tidal flows within the Loxahatchee River estuary are reproduced to provide: 1) recommendations for the domain extent of an integrated, surface/groundwater, three-dimensional model; 2) nearshore, harmonically decomposed, tidal elevation boundary conditions. Tidal simulations are performed using a two-dimensional, depth-integrated, finite element-based code for coastal and ocean circulation, ADCIRC-2DDI. Multiple variations of an unstructured, finite element mesh are applied to encompass the Loxahatchee River estuary and different spatial extents of the Atlantic Intracoastal Waterway (AIW). Phase and amplitude errors between model output and historical data are quantified at five locations within the Loxahatchee River estuary to emphasize the importance of including the AIW in the computational domain. In addition, velocity residuals are computed globally to reveal significantly different net circulation patterns within the Loxahatchee River estuary, as depending on the spatial coverage of the AIW.

L'objectif principal de cette thèse était de reconstituer l'évolution de la circulation intermédiaire depuis la dernière période glaciaire à partir de carottes de sédiments marins prélevées dans le golfe du Bengale GB, la Mer d’Arabie MA et l’océan Indien équatorial oriental OIEO. La stratégie scientifique mise en œuvre inclut l’étude des assemblages et de la géochimie des foraminifères benthiques, afin de reconstruire les changements de source et de ventilation des masses d’eau. Les résultats obtenus dans le GB ont permis de restituer les changements hydrologiques à profondeur intermédiaire à haute résolution temporelle au cours des derniers 40 ka. Les enregistrements témoignent de changements dans la source des masses d’eau, entre l’Océan austral avec les eaux antarctiques intermédiaires AAIW et les eaux Nord Atlantique NADW, à l’échelle glaciaire-interglaciaire mais aussi lors des événements millénaires. Ce travail a aussi permis de fournir les premiers enregistrements à haute résolution temporelle des rapports élémentaires des foraminifères benthiques (Mg/Ca, Sr/Ca, U/Ca et Li/Ca) dans le GB et en MA. Ces résultats permettent notamment de mieux contraindre la pénétration des AAIW vers le nord depuis la dernière période glaciaire. La reconstruction de la concentration en ion carbonate permet également de discuter des relations entre les variations de la circulation intermédiaire et les changements profonds du cycle du Carbone à l’échelle globale, notamment via les échanges se produisant dans l’Océan Austral. Nous avons également fourni dans ce travail les premiers enregistrements de Cd/Ca et de Ba/Ca continus et à haute résolution dans le nord de l’océan Indien, pour reconstituer les modifications passées de la teneur en éléments nutritifs. Les enregistrements géochimiques dans l’OIEO témoignent de profonds changements des propriétés des masses d'eau intermédiaires, associées aux changements de circulation. / The main objective of this study was to reconstruct the evolution of the intermediate water circulation since the last glacial period by the investigation of marine cores collected from the Bay of Bengal (BoB), Arabian Sea (AS) and Eastern Equatorial Indian Ocean (EEIO). The scientific strategy involves benthic foraminiferal assemblages and geochemical proxies to better constrain past changes in the source and ventilation of water masses. Records from the BoB allowed reconstructing hydrological changes at intermediate depth over the last 40 cal kyr. The records highlight changes in the source of water masses, with a balance between the contribution of southern Antarctic Intermediate Water (AAIW) versus North Atlantic Deep Water (NADW) at glacial-interglacial timescale as well as during millennial events. This work also provided the first high-resolution benthic foraminifera elemental ratio records (Mg/Ca, Sr/Ca, U/Ca and Li/Ca) from the BoB and the AS. These records especially help to better constrain the northward penetration of AAIW over the last glacial period. The reconstruction of the carbonate ion concentration allowed to discuss the relationships between the intermediate water circulation and deep changes in the global Carbon cycle, with a special interest for the Southern Ocean. This work also provides the first continuous and high-resolution benthic Cd/Ca and Ba/Ca records in the northern Indian Ocean, could reconstruct past changes in the nutrient content. Geochemical records from the EEIO exhibit strong changes in the chemical properties of the intermediate water masses, related to global circulation changes in the area.

Arbetet innefattar en undersökning kring vattenreservoarer där magasinsvolymer och konstruktionslösningar utreds samt analyseras. I nuläget saknas tydliga riktlinjer för hur reservoarer i mindre samhällen ska utformas och dimensioneras för att säkerställa vattenkvalitén och uppnå en säker vattenförsörjning. Målet och syftet med arbetet är att ta fram en magasinsvolym, identifiera viktiga aspekter att ta hänsyn till vid utformning av en reservoar samt presentera fördelar med och behovet av en vattenreservoar utifrån förbrukningsvariationer. Arbetet avgränsas till Lammhults förutsättningar där intervjuer, observationer, litteraturstudier, analyser och beräkningar ligger till grund för teori och resultat. Resultatet påvisar bland annat svårigheter i att analysera förbrukningsvariationer, vikten av lokal korrekt statistik och ifrågasättande av befintligt dimensioneringssätt för magasinsvolym. Arbetet kartlägger delvis vissa problemområden men vidare studier krävs för att fastställa lösningar inom områdena. Genom detta kan tydliga riktlinjer för att dimensionera och utforma en reservoar tas fram. / The essay contains an assessment of water reservoirs, where an examination and analysis of storage volumes and construction solutions are carried out. Today there are no clear guidelines for how reservoirs in smaller communities should be designed and dimensioned to ensure water quality and guarantee a safe water supply. The goal and purpose of the essay is to calculate a storage volume, identify important aspects to consider in designing a reservoir, and present advantages with and the need of a water reservoir based on consumption variations. The assessment is limited to Lammhults’s conditions where interviews, observations, literature studies, analyses and calculations serve as a foundation for the theory and the result. The result demonstrates, among other things, difficulties, difficulties in analyzing consumption variations, the importance of local correct statistics and questioning of existing methods of dimensioning a storage volume. The essay partially some problem areas, but further studies are required to find solutions in the sector and straight guidelines regarding dimensions and design of reservoirs.

This thesis aims to increase photovoltaic (PV) panel power efficiency by employing a cooling system based on water circulation, which represents an improved version of water flow based active cooling systems. Theoretical calculations involved finding the heat produced by the PV panel and the circulation water flow required to remove this heat. A data logger and a cooling system for a test panel of 20W was designed and employed to study the relationship between the PV panel surface temperature and its output power. This logging and cooling system includes an Arduino microcontroller extended with a data logging shield, temperature sensing probes, current sensors, and a DC water pump. Real-time measurements were logged every minute for one or two day periods under various irradiance and air temperature conditions. For these experiments, a load resistance was chosen to operate the test panel at its maximum power point. Results indicate that the cooling system can yield an improvement of 10% in power production. Based on the observations from the test panel experiments, a cooling system was devised for a PV panel array of 640 W equipped with a commercial charge controller. The test data logger was repurposed for this larger system. An identical PV array was left uncooled and monitored simultaneously to compare the effect of cooling, demonstrating that the cooled array provided up to an extra 132W or 20% of maximum power for sunny weather conditions. Future expansion possibilities of the project include automated water level monitoring system and water filtration systems.