Russian metals for arctic offshore structures

With an increasingly growing demand for natural resources, the Arctic region has become an attractive area, holding about 15% of world oil. Ice shrinkage caused by global warming encourages the development of offshore and ship-building sectors. Russia, as one of the leading oil and gas production countries is participating actively in cold resistant materials research, since half of its territory belongs to the Arctic environment, which held considerable stores of oil. Nowadays most Russian offshore platforms are located in the Sakhalin Island area, which geographically does not belong to the Arctic, but has com-parable environmental conditions. Russia recently has manufactured several offshore platforms. It became clear that further development of the Arctic off-shore structures with necessary reliability is highly depending on the materials employed. This work pursues the following objectives:  to provide a comprehensive review on Russian metals used for Arctic offshore structures on the base of standards, books, journal articles and companies reports  to overview various Arctic offshore structures and its structural characteristics  briefly discuss materials testing methods for low temperatures Master`s thesis focuses on specifications and description of Russian metals which are already in use and can be used for Arctic offshore structures. Work overviews several groups of steel, such as low carbon, low alloy, chromium containing steels, stainless steels, aluminium and nanostructured steels. Materials under discussion are grouped based on the standards, for instance the work covers shipbuilding and structural steels at the different sections. This paper provides an overview of important Russian Arctic offshore projects built for use in Russia and ordered by foreign countries. Future trends in development of the Arctic materials are discussed. Based on the information provided in this Master`s thesis it is possible to learn about Russian metals used for ships and offshore platforms operated in the Arctic region. Paper can be used as the comprehensive review of current materials, such as various steels, aluminium and nanomaterials.

Reflexive Space. A Constructionist Model of the Russian Reflexive Marker

This study examines the structure of the Russian Reflexive Marker ( ся/-сь) and offers a usage-based model building on Construction Grammar and a probabilistic view of linguistic structure. Traditionally, reflexive verbs are accounted for relative to non-reflexive verbs. These accounts assume that linguistic structures emerge as pairs. Furthermore, these accounts assume directionality where the semantics and structure of a reflexive verb can be derived from the non-reflexive verb. However, this directionality does not necessarily hold diachronically. Additionally, the semantics and the patterns associated with a particular reflexive verb are not always shared with the non-reflexive verb. Thus, a model is proposed that can accommodate the traditional pairs as well as for the possible deviations without postulating different systems. A random sample of 2000 instances marked with the Reflexive Marker was extracted from the Russian National Corpus and the sample used in this study contains 819 unique reflexive verbs. This study moves away from the traditional pair account and introduces the concept of Neighbor Verb. A neighbor verb exists for a reflexive verb if they share the same phonological form excluding the Reflexive Marker. It is claimed here that the Reflexive Marker constitutes a system in Russian and the relation between the reflexive and neighbor verbs constitutes a cross-paradigmatic relation. Furthermore, the relation between the reflexive and the neighbor verb is argued to be of symbolic connectivity rather than directionality. Effectively, the relation holding between particular instantiations can vary. The theoretical basis of the present study builds on this assumption. Several new variables are examined in order to systematically model variability of this symbolic connectivity, specifically the degree and strength of connectivity between items. In usage-based models, the lexicon does not constitute an unstructured list of items. Instead, items are assumed to be interconnected in a network. This interconnectedness is defined as Neighborhood in this study. Additionally, each verb carves its own niche within the Neighborhood and this interconnectedness is modeled through rhyme verbs constituting the degree of connectivity of a particular verb in the lexicon. The second component of the degree of connectivity concerns the status of a particular verb relative to its rhyme verbs. The connectivity within the neighborhood of a particular verb varies and this variability is quantified by using the Levenshtein distance. The second property of the lexical network is the strength of connectivity between items. Frequency of use has been one of the primary variables in functional linguistics used to probe this. In addition, a new variable called Constructional Entropy is introduced in this study building on information theory. It is a quantification of the amount of information carried by a particular reflexive verb in one or more argument constructions. The results of the lexical connectivity indicate that the reflexive verbs have statistically greater neighborhood distances than the neighbor verbs. This distributional property can be used to motivate the traditional observation that the reflexive verbs tend to have idiosyncratic properties. A set of argument constructions, generalizations over usage patterns, are proposed for the reflexive verbs in this study. In addition to the variables associated with the lexical connectivity, a number of variables proposed in the literature are explored and used as predictors in the model. The second part of this study introduces the use of a machine learning algorithm called Random Forests. The performance of the model indicates that it is capable, up to a degree, of disambiguating the proposed argument construction types of the Russian Reflexive Marker. Additionally, a global ranking of the predictors used in the model is offered. Finally, most construction grammars assume that argument construction form a network structure. A new method is proposed that establishes generalization over the argument constructions referred to as Linking Construction. In sum, this study explores the structural properties of the Russian Reflexive Marker and a new model is set forth that can accommodate both the traditional pairs and potential deviations from it in a principled manner.

The effects of welding heat input on the usability of high strength steels in welded structures

High strength steel (HSS) has been in use in workshops since the 1980s. At that time, the significance of the term HSS differed from the modern conception as the maximum yield strength of HSSs has increased nearly every year. There are three different ways to make HSS. The first and oldest method is QT (quenched and tempered) followed by the TMCP (thermomechanical controlled process) and DQ (direct quenching) methods. This thesis consists of two parts, the first of which part introduces the research topic and discusses welded HSS structures by characterizing the most important variables. In the second part of the thesis, the usability of welded HSS structures is examined through a set of laboratory tests. The results of this study explain the differences in the usability of the welded HSSs made by the three different methods. The results additionally indicate that usage of different HSSs in the welded structures presumes that manufacturers know what kind of HSS they are welding. As manufacturers use greater strength HSSs in welded structures, the demands for welding rise as well. Therefore, during the manufacturing process, factors such as heat input, cooling time, weld quality, and more must be under careful observation.

Knowledge, processes and relationships in organizational change: Understanding how to facilitate management of intellectual capital in diverse organization structures and cultures.

This study examined relationships of organizational dependencies, change management and developed intellectual knowledge resources, in different intellectual capital based development programs on ICT-sector. Study was carried out in a research context, where high degree of external organizational contingencies existed and lots of changes in several development programs had taken place in the last years. From a scientific perspective the main contribution was that evidence between relationships of organizational dependencies, change model portfolio and developed knowledge resources could be suggested. From managerial perspective the primary implication was that in situations where sustainable competitive advantage is pursued by means of increasing knowledge based productivity of labor, firms should seek to pursue organizational settings where external dependencies have minimal amount of effect.

The nature of communication structures of university students in an international web-based computer-supported collaborative learning (CSCL) course

Communication, the flow of ideas and information between individuals in a social context, is the heart of educational experience. Constructivism and constructivist theories form the foundation for the collaborative learning processes of creating and sharing meaning in online educational contexts. The Learning and Collaboration in Technology-enhanced Contexts (LeCoTec) course comprised of 66 participants drawn from four European universities (Oulu, Turku, Ghent and Ramon Llull). These participants were split into 15 groups with the express aim of learning about computer-supported collaborative learning (CSCL). The Community of Inquiry model (social, cognitive and teaching presences) provided the content and tools for learning and researching the collaborative interactions in this environment. The sampled comments from the collaborative phase were collected and analyzed at chain-level and group-level, with the aim of identifying the various message types that sustained high learning outcomes. Furthermore, the Social Network Analysis helped to view the density of whole group interactions, as well as the popular and active members within the highly collaborating groups. It was observed that long chains occur in groups having high quality outcomes. These chains were also characterized by Social, Interactivity, Administrative and Content comment-types. In addition, high outcomes were realized from the high interactive cases and high-density groups. In low interactive groups, commenting patterned around the one or two central group members. In conclusion, future online environments should support high-order learning and develop greater metacognition and self-regulation. Moreover, such an environment, with a wide variety of problem solving tools, would enhance interactivity.

Tehollisen lovijännityksen menetelmän käytettävyys ultralujien terästen korkealaatuisten hitsien väsymismitoituksessa

Tässä diplomityössä on tutkittu tehollisen lovijännityksen menetelmän soveltuvuutta ultralujien terästen korkealaatuisten hitsien väsymismitoitukseen. International Institute of Welding suosittelee käyttämään elementtimenetelmässä hitsin rajaviivoilla sekä juuressa fiktiivistä 1 mm pyöristystä, jonka avulla tehollinen lovijännitys määritetään. Kaikille liitostyypeille sovelletaan samaa, kaltevuudeltaan m = 3 olevaa SN-käyrää, jolloin maksimipääjännitystä vastaava väsymisluokka FAT saa arvon 225. Nykyisiä mitoitusohjeita on pidetty kuitenkin liian konservatiivisina, etenkin jos kyseessä on suurilujuuksisesta teräksestä valmistettu korkealaatuinen hitsi. Rajaviivalla vaikuttavaa lovijännitystä on tutkittu mallintamalla liitokset FEMAP – elementtimenetelmäohjelmalla varioimalla rajaviivan pyöristystä. Elementtimenetelmän tuloksia on verrattu analyyttisiin loven muotoluvun laskentakaavoihin. Tutkittavana on ollut Ruukin Optim 960 QC sekä Optim 1100 QC – teräksistä valmistettuja koesauvoja. Koesauvat on valmistettu sekä koestettu pääasiassa Lappeenrannan teknillisen yliopiston teräsrakenteiden laboratoriossa. Tutkittavat koesauvat ovat olleet kuormaa kantamattomia ristiliitoksia sekä päittäisliitoksia. Suurin osa koesauvoista on väsytetty käyttämällä jännityssuhdetta R < 0,11. Koesauvat on jaoteltu jännityssuhteen sekä liitostyypin mukaan. Kaikkien koekappaleiden karakteristiseksi väsymisluokan arvoksi on määritetty FAT 200. Alle 0,11 jännityssuhteella väsytettyjen koekappaleiden karakteristinen väsymisluokka on FAT 230 ja isoilla jännityssuhteilla väsytettyjen FAT 126. Tulosten perusteella nykyiset mitoitusohjeet eivät ole liian konservatiivisia. Väsymisluokkaa FAT 225 voidaan käyttää väsymislaskennassa, mikäli rakenteen kuormitusten suhde on alle 0,1. Isoilla jännityssuhteilla koestettujen koekappaleiden lukumäärä on ollut pieni, joten niiden mitoitukselle ei voida antaa tarkkoja ohjeita.

Variable speed drive in fan system monitoring

Fan systems are responsible for approximately 10% of the electricity consumption in industrial and municipal sectors, and it has been found that there is energy-saving potential in these systems. To this end, variable speed drives (VSDs) are used to enhance the efficiency of fan systems. Usually, fan system operation is optimized based on measurements of the system, but there are seldom readily installed meters in the system that can be used for the purpose. Thus, sensorless methods are needed for the optimization of fan system operation. In this thesis, methods for the fan operating point estimation with a variable speed drive are studied and discussed. These methods can be used for the energy efficient control of the fan system without additional measurements. The operation of these methods is validated by laboratory measurements and data from an industrial fan system. In addition to their energy consumption, condition monitoring of fan systems is a key issue as fans are an integral part of various production processes. Fan system condition monitoring is usually carried out with vibration measurements, which again increase the system complexity. However, variable speed drives can already be used for pumping system condition monitoring. Therefore, it would add to the usability of a variablespeed- driven fan system if the variable speed drive could be used as a condition monitoring device. In this thesis, sensorless detection methods for three lifetime-reducing phenomena are suggested: these are detection of the fan contamination build-up, the correct rotational direction, and the fan surge. The methods use the variable speed drive monitoring and control options for the detection along with simple signal processing methods, such as power spectrum density estimates. The methods have been validated by laboratory measurements. The key finding of this doctoral thesis is that a variable speed drive can be used on its own as a monitoring and control device for the fan system energy efficiency, and it can also be used in the detection of certain lifetime-reducing phenomena.

Optimization of strength and toughness on the effect of the weldable high strength steels (hss) used in offshore structures

Optimization of high strength and toughness combination on the effect of weldability is very vital to be considered in offshore oil and gas industries. Having a balanced and improved high strength and toughness is very much recommended in offshore structures for an effective production and viable exploration of hydrocarbons. This thesis aims to investigate the possibilities to improve the toughness of high strength steel. High carbon contents induce hardness and needs to be reduced for increasing toughness. The rare combination of high strength with high toughness possibilities was examined by determining the following toughening mechanism of: Heat treatment and optimal microstructure, Thermomechanical processing, Effect of welding parameters on toughness and weldability of steel. The implementation of weldability of steels to attain high toughness for high strength in offshore structures is mostly in shipbuilding, offshore platforms, and pipelines for high operating pressures. As a result, the toughening mechanisms suggested have benefits to the aims of the effect of high strength to high toughness of steel for efficiency, production and cost reduction.

Energy-efficient control strategies for variable speed driven parallel pumping systems based on pump operation point monitoring with frequency converters

The pumping processes requiring wide range of flow are often equipped with parallelconnected centrifugal pumps. In parallel pumping systems, the use of variable speed control allows that the required output for the process can be delivered with a varying number of operated pump units and selected rotational speed references. However, the optimization of the parallel-connected rotational speed controlled pump units often requires adaptive modelling of both parallel pump characteristics and the surrounding system in varying operation conditions. The available information required for the system modelling in typical parallel pumping applications such as waste water treatment and various cooling and water delivery pumping tasks can be limited, and the lack of real-time operation point monitoring often sets limits for accurate energy efficiency optimization. Hence, alternatives for easily implementable control strategies which can be adopted with minimum system data are necessary. This doctoral thesis concentrates on the methods that allow the energy efficient use of variable speed controlled parallel pumps in system scenarios in which the parallel pump units consist of a centrifugal pump, an electric motor, and a frequency converter. Firstly, the suitable operation conditions for variable speed controlled parallel pumps are studied. Secondly, methods for determining the output of each parallel pump unit using characteristic curve-based operation point estimation with frequency converter are discussed. Thirdly, the implementation of the control strategy based on real-time pump operation point estimation and sub-optimization of each parallel pump unit is studied. The findings of the thesis support the idea that the energy efficiency of the pumping can be increased without the installation of new, more efficient components in the systems by simply adopting suitable control strategies. An easily implementable and adaptive control strategy for variable speed controlled parallel pumping systems can be created by utilizing the pump operation point estimation available in modern frequency converters. Hence, additional real-time flow metering, start-up measurements, and detailed system model are unnecessary, and the pumping task can be fulfilled by determining a speed reference for each parallel-pump unit which suggests the energy efficient operation of the pumping system.

Flavonoids and other phenolic compounds: characterization and interactions with lepidopteran and sawfly larvae

This thesis focuses on flavonoids, a subgroup of phenolic compounds produced by plants, and how they affect the herbivorous larvae of lepidopterans and sawflies. The first part of the literature review examines different techniques to analyze the chemical structures of flavonoids and their concentrations in biological samples. These techniques include, for example, ultraviolet-visible spectroscopy, mass spectrometry, and nuclear magnetic resonance spectroscopy. The second part of the literature review studies how phenolic compounds function in the metabolism of larvae. The harmful oxidation reactions of phenolic compounds in insect guts are also emphasized. In addition to the negative effects, many insect species have evolved the use of phenolic compounds for their own benefit. In the experimental part of the thesis, high concentrations of complex flavonoid oligoglycosides were found in the hemolymph (the circulatory fluid of insects) of birch and pine sawflies. The larvae produced these compounds from simple flavonoid precursors present in the birch leaves and pine needles. Flavonoid glycosides were also found in the cocoon walls of sawflies, which suggested that flavonoids were used in the construction of cocoons. The second part of the experimental work studied the modifications of phenolic compounds in conditions that mimicked the alkaline guts of lepidopteran larvae. It was found that the 24 plant species studied and their individual phenolic compounds had variable capacities to function as oxidative defenses in alkaline conditions. The excrements of lepidopteran and sawfly species were studied to see how different types of phenolics were processed by the larvae. These results suggested that phenolic compounds were oxidized, hydrolyzed, or modified in other ways during their passage through the digestive tract of the larvae.

Development of finite elements for analysis of biomechanical structures using flexible multibody formulations

The absolute nodal coordinate formulation was originally developed for the analysis of structures undergoing large rotations and deformations. This dissertation proposes several enhancements to the absolute nodal coordinate formulation based finite beam and plate elements. The main scientific contribution of this thesis relies on the development of elements based on the absolute nodal coordinate formulation that do not suffer from commonly known numerical locking phenomena. These elements can be used in the future in a number of practical applications, for example, analysis of biomechanical soft tissues. This study presents several higher-order Euler–Bernoulli beam elements, a simple method to alleviate Poisson’s and transverse shear locking in gradient deficient plate elements, and a nearly locking free gradient deficient plate element. The absolute nodal coordinate formulation based gradient deficient plate elements developed in this dissertation describe most of the common numerical locking phenomena encountered in the formulation of a continuum mechanics based description of elastic energy. Thus, with these fairly straightforwardly formulated elements that are comprised only of the position and transverse direction gradient degrees of freedom, the pathologies and remedies for the numerical locking phenomena are presented in a clear and understandable manner. The analysis of the Euler–Bernoulli beam elements developed in this study show that the choice of higher gradient degrees of freedom as nodal degrees of freedom leads to a smoother strain field. This improves the rate of convergence.

Lebesgue and Sobolev spaces with variable exponents

Kirjallisuusarvostelu

Development of a Glycocluster Adjuvant Mimicking Natural Yeast beta-(1,2)-Structures

Allergy is characterized by T helper (Th) 2-type immune response after encounter with an allergen leading to subsequent immunoglobulin (Ig) E-mediated hypersensitivity reaction and further allergic inflammation. Allergen-specific immunotherapy (SIT) balances the Th2-biased immunity towards Th1 and T regulatory responses. Adjuvants are used in allergen preparations to intensify and modify SIT. β-(1,2)-oligomannoside constituents present in Candida albicans (C. albicans) cell wall possess Th1-type immunostimulatory properties. The aim of this thesis was to develop a β-(1,2)-linked carbohydrate compound with known structure and anti-allergic properties to be applied as an adjuvant in SIT. First the immunostimulatory properties of various fungal extracts were studied. C. albicans appeared to be the most promising Th1-inducing extract, which led to the synthesis of various mono- or divalent oligomannosides designed on the basis of C. albicans. These carbohydrates did not induce strong cytokine production in human peripheral blood mononuclear cell (PBMC) cultures. In contrast to earlier reports using native oligosaccharides from C. albicans, synthetic -(1,2)-linked mannotetraose did not induce any tumor necrosis factor production in murine macrophages. Next, similarities with synthesized divalent mannosides and the antigenic epitopes of β-(1,2)-linked C. albicans mannan were investigated. Two divalent compounds inhibited specific IgG antibodies binding to below 3 kDa hydrolyzed mannan down to the level of 30–50% showing similar antigenicity to C. albicans. Immunomodulatory properties of synthesized carbohydrate assemblies ranging from mono- to pentavalent were evaluated. A trivalent acetylated dimannose (TADM) induced interleukin-10 (IL-10) and interferon-γ responses. TADM also suppressed birch pollen induced IL-4 and IL-5 responses in allergen (Bet v) stimulated PBMCs of birch pollen allergic subjects. This suppression was stronger with TADM than with other used adjuvants, immunostimulatory oligonucleotides and monophosphoryl lipid A. In a murine model of asthma, the allergen induced inflammatory responses could also be suppressed by TADM on cytokine and antibody levels.

Hyperfine interactions in the new Fe-based superconducting structures and related magnetic phases

This thesis is devoted to the study of the hyperfine properties in iron-based superconductors and the synthesis of these compounds and related phases. During this work polycrystalline chalcogenide samples with stoichiometry 1:1 (FeTe1-χSχ, FeSe1-x) and pnictide samples with stoichiometry 1:2:2 (BaFe2(As1-χPχ)2, EuFe2(As1-x Px)2) were synthesized by solid-state reaction methods in vacuum and in a protecting Ar atmosphere. In several cases post-annealing in oxygen atmosphere was employed. The purity and superconducting properties of the obtained samples were checked with X-ray diffraction, SQUID and resistivity measurements. For studies of the magnetic properties of the investigated samples Mössbauer spectroscopy was used. Using low-temperature measurements around Tc and various values of the source velocity the hyperfine interactions were obtained and the magnetic and structural properties in the normal and superconducting states could be studied. Mössbauer measurements together with XRD characterization were also used for the detection of impurity phases. DFT calculations were used for the theoretical study of Mössbauer parameters for pnictide-based ᴻsamples BaFe2(As1-xPx)2 and EuFe2(As1-xPx)2.

Genesis and Evolution of Brittle Structures In Southwestern Finland and Western South Africa. Insights into Fault Reactivation, Fluid Flow and Structural Maturity in Precambrian Cratons

The bedrock of old crystalline cratons is characteristically saturated with brittle structures formed during successive superimposed episodes of deformation and under varying stress regimes. As a result, the crust effectively deforms through the reactivation of pre-existing structures rather than by through the activation, or generation, of new ones, and is said to be in a state of 'structural maturity'. By combining data from Olkiluoto Island, southwestern Finland, which has been investigated as the potential site of a deep geological repository for high-level nuclear waste, with observations from southern Sweden, it can be concluded that the southern part of the Svecofennian shield had already attained structural maturity during the Mesoproterozoic era. This indicates that the phase of activation of the crust, i.e. the time interval during which new fractures were generated, was brief in comparison to the subsequent reactivation phase. Structural maturity of the bedrock was also attained relatively rapidly in Namaqualand, western South Africa, after the formation of first brittle structures during Neoproterozoic time. Subsequent brittle deformation in Namaqualand was controlled by the reactivation of pre-existing strike-slip faults.In such settings, seismic events are likely to occur through reactivation of pre-existing zones that are favourably oriented with respect to prevailing stresses. In Namaqualand, this is shown for present day seismicity by slip tendency analysis, and at Olkiluoto, for a Neoproterozoic earthquake reactivating a Mesoproterozoic fault. By combining detailed field observations with the results of paleostress inversions and relative and absolute time constraints, seven distinctm superimposed paleostress regimes have been recognized in the Olkiluoto region. From oldest to youngest these are: (1) NW-SE to NNW-SSE transpression, which prevailed soon after 1.75 Ga, when the crust had sufficiently cooled down to allow brittle deformation to occur. During this phase conjugate NNW-SSE and NE-SW striking strike-slip faults were active simultaneous with reactivation of SE-dipping low-angle shear zones and foliation planes. This was followed by (2) N-S to NE-SW transpression, which caused partial reactivation of structures formed in the first event; (3) NW-SE extension during the Gothian orogeny and at the time of rapakivi magmatism and intrusion of diabase dikes; (4) NE-SW transtension that occurred between 1.60 and 1.30 Ga and which also formed the NW-SE-trending Satakunta graben located some 20 km north of Olkiluoto. Greisen-type veins also formed during this phase. (5) NE-SW compression that postdates both the formation of the 1.56 Ga rapakivi granites and 1.27 Ga olivine diabases of the region; (6) E-W transpression during the early stages of the Mesoproterozoic Sveconorwegian orogeny and which also predated (7) almost coaxial E-W extension attributed to the collapse of the Sveconorwegian orogeny. The kinematic analysis of fracture systems in crystalline bedrock also provides a robust framework for evaluating fluid-rock interaction in the brittle regime; this is essential in assessment of bedrock integrity for numerous geo-engineering applications, including groundwater management, transient or permanent CO2 storage and site investigations for permanent waste disposal. Investigations at Olkiluoto revealed that fluid flow along fractures is coupled with low normal tractions due to in-situ stresses and thus deviates from the generally accepted critically stressed fracture concept, where fluid flow is concentrated on fractures on the verge of failure. The difference is linked to the shallow conditions of Olkiluoto - due to the low differential stresses inherent at shallow depths, fracture activation and fluid flow is controlled by dilation due to low normal tractions. At deeper settings, however, fluid flow is controlled by fracture criticality caused by large differential stress, which drives shear deformation instead of dilation.