Map illustrating the site of the harbours for the proposed Obi-railway : the soundings are all calculated in feet and are based upon the data of the Russian Marine Ministry : the underlined figures are soundings taken by the scooner Bakan, 1887

Kartta kuuluu A. E. Nordenskiöldin kokoelmaan

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.

Time to volume through efficient multi-site ramp-up

The aim of this thesis was to create a process for all multi-site ramp-up (MSRU) projects in the case company in order to have simultaneous ramp-ups early in the market. The research was done through case study in one company and semi-structured interviews. There are already processes, which are now in use in MSRU-cases. Interviews of 20 ramp-up specialists revealed topics to be improved. Those were project team set up, roles and responsibilities and recommended project organization, communication, product change management practices, competence and know how transfer practices and support model. More R&D support and involvement is needed in MSRU-projects. DCM’s role is very important in the MSRU-projects among PMT-team; he should be the business owner of the project. Recommendation is that product programs could take care of the product and repair training of new products in volume factories. R&D’s participation in competence transfers is essential important in MSRU-projects. Communication in projects could be shared through special intranet commune. Blogging and tweeting could be considered in the communication plan. If hundreds of change notes are open in ramp-up phase, it should be considered not to approve the product into volume ramp-up. PMTs’ supports are also important and MSRU-projects should be planned, budgeted and executed together. Finally a new MSRU-process is presented in this thesis to be used in all MSRU-projects.

Developing construction site operations for EPC power plant projects

The purpose of this thesis is to find development areas for site operations in power plant construction projects delivered by Wärtsilä. The inspected operations are subcontractor management, site material management and work scheduling. The contractor's role in EPC project is to respond for engineering, procurement, and construction supervision. Geographical and cultural differences brings challenges for finding development areas as Wärtsilä delivers projects world-wide. Searching for development area is mainly made with survey, which answers were collected from the target company's site personnel. Based on the results, with good planning and preparation various problems would be avoided. An external view for the thesis was collected by an expert interview, which was held to three expe-rienced construction operating executives. Interviewees believed that with the se-lection of right site personnel and clearly defined areas of responsibility will great-ly affect the outcome of the project. Some of the theory has been collected from areas, which have helped to under-stand the inspected operations on site. Improving competence knowledge has been important due to the broad scope of work and the author’s inexperience of the topic. Also generally effective practices from construction projects has been col-lected to the theory part. Functionality of general practices have been reflected together with the results of empirically collected data for Wärtsilä's projects. As a result, a model was generated where development proposals and the benefits from new procedures were presented.

The Role of Structural Imperfections in Sr2FeMoO6 Thin Films

In this work, Sr2FeMoO6 (SFMO) thin films were studied with the main focus on their magnetic and magneto-transport properties. The fabrication process of pulsed laser deposited SFMO films was first optimized. Then the effects of strain, film thickness and substrate were thoroughly investigated. In addition to these external factors, the effect of intrinsic defects on the magnetic properties of SFMO were also clarified. Secondly, the magnetoresistivity mechanims of SFMO films were studied and a semiempirical model of the temperature dependence of resistivity was introduced. The films were grown on single crystal substrates using a ceramic target made with sol-gel method. The structural characterization of the films were carried out with X-ray diffraction, atomic force microscopy, transmission electron microscopy and high kinetic energy photoelectron spectroscopy. The magnetic properties were measured with SQUID magnetometer and the magneto-transport properties by magnetometer with a resistivity option. SFMO films with the best combination of structural and magnetic properties were grown in Ar atmosphere at 1050 °C . Their magnetic properties could not be improved by the ex situ post-annealing treatments aside from the treatments in ultra-high vacuum conditions. The optimal film thickness was found to be around 150 nm and only small improvement in the magnetic properties with decreasing strain was observed. Instead, the magnetic properties were observed to be highly dependent on the choice of the substrate due to the lattice mismatch induced defects, which are best avoided by using the SrTiO3 substrate. The large difference in the Curie temperature and the saturation magnetization between the SFMO thin film and polycrystalline bulk samples was connected to the antisite disorder and oxygen vacancies. Thus, the Curie temperature of SFMO thin films could be improved by increasing the amount of oxygen vacancies for example with ultra-high vacuum treatments or improving the B-site ordering by further optimization of the deposition parameters. The magneto-transport properties of SFMO thin films do not follow any conventional models, but the temperature dependence of resistivity was succesfully described with a model of two spin channel system. Also, evidences that the resistivity-temperature behaviour of SFMO thin films is dominated by the structural defects, which reduce the band gap in the majority spin band were found. Moreover, the magnetic field response of the resistivity in SFMO thin films were found to be superposition of different mechanisms that seems to be related to the structural changes in the film.

On site measurements of DC link electrolytic capacitor bank of frequency converter using constant DC magnetization of the motor

Preventive maintenance of frequency converters has been based on pre-planned replace-ment of wearing or ageing components. Exchange intervals follow component life-time expectations which are based on empirical knowledge or schedules defined by manufac-turer. However, the lifetime of a component can vary significantly, because drives are used in very different operating environments and applications. The main objective of the research was to provide information on methods, i.e. how in-verter's operating condition can be measured reliably under field conditions. At first, the research focused on critical components such as current transducers, IGBTs and DC link capacitor bank, because these aging have already been identified. Of these, the DC link capacitor measurement method was selected for closer examination. With this method, the total capacitance and its total series resistance can be measured. The suitability of the measuring procedure was estimated on the basis of practical measurements. The research was made by using so called triangulation method, including a literature review, simulations and practical measurements. Based on the results, the new measu-rement method seems suitable with some reservations to practical measurements. How-ever, the measuring method should be further developed in order to improve its reliability.