Local and Global Feature Extraction for Invariant Object Recognition

Perceiving the world visually is a basic act for humans, but for computers it is still an unsolved problem. The variability present innatural environments is an obstacle for effective computer vision. The goal of invariant object recognition is to recognise objects in a digital image despite variations in, for example, pose, lighting or occlusion. In this study, invariant object recognition is considered from the viewpoint of feature extraction. Thedifferences between local and global features are studied with emphasis on Hough transform and Gabor filtering based feature extraction. The methods are examined with respect to four capabilities: generality, invariance, stability, and efficiency. Invariant features are presented using both Hough transform and Gabor filtering. A modified Hough transform technique is also presented where the distortion tolerance is increased by incorporating local information. In addition, methods for decreasing the computational costs of the Hough transform employing parallel processing and local information are introduced.

Switchable lanthanide fluorescence probes in homogenous molecular diagnostics

The number of molecular diagnostic assays has increased tremendously in recent years.Nucleic acid diagnostic assays have been developed, especially for the detection of human pathogenic microbes and genetic markers predisposing to certain diseases. Closed-tube methods are preferred because they are usually faster and easier to perform than heterogenous methods and in addition, target nucleic acids are commonly amplified leading to risk of contamination of the following reactions by the amplification product if the reactions are opened. The present study introduces a new closed-tube switchable complementation probes based PCR assay concept where two non-fluorescent probes form a fluorescent lanthanide chelate complex in the presence of the target DNA. In this dual-probe PCR assay method one oligonucleotide probe carries a non-fluorescent lanthanide chelate and another probe a light absorbing antenna ligand. The fluorescent lanthanide chelate complex is formed only when the non-fluorescent probes are hybridized to adjacent positions into the target DNA bringing the reporter moieties in close proximity. The complex is formed by self-assembled lanthanide chelate complementation where the antenna ligand is coordinated to the lanthanide ion captured in the chelate. The complementation probes based assays with time-resolved fluorescence measurement showed low background signal level and hence, relatively high nucleic acid detection sensitivity (low picomolar target concentration). Different lanthanide chelate structures were explored and a new cyclic seven dentate lanthanide chelate was found suitable for complementation probe method. It was also found to resist relatively high PCR reaction temperatures, which was essential for the PCR assay applications. A seven-dentate chelate with two unoccupied coordination sites must be used instead of a more stable eight- or nine-dentate chelate because the antenna ligand needs to be coordinated to the free coordination sites of the lanthanide ion. The previously used linear seven-dentate lanthanide chelate was found to be unstable in PCR conditions and hence, the new cyclic chelate was needed. The complementation probe PCR assay method showed high signal-to-background ratio up to 300 due to a low background fluorescence level and the results (threshold cycles) in real-time PCR were reached approximately 6 amplification cycles earlier compared to the commonly used FRET-based closed-tube PCR method. The suitability of the complementation probe method for different nucleic acid assay applications was studied. 1) A duplex complementation probe C. trachomatis PCR assay with a simple 10-minute urine sample preparation was developed to study suitability of the method for clinical diagnostics. The performance of the C. trachomatis assay was equal to the commercial C. trachomatis nucleic acid amplification assay containing more complex sample preparation based on DNA extraction. 2) A PCR assay for the detection of HLA-DQA1*05 allele, that is used to predict the risk of type 1 diabetes, was developed to study the performance of the method in genotyping. A simple blood sample preparation was used where the nucleic acids were released from dried blood sample punches using high temperature and alkaline reaction conditions. The complementation probe HLA-DQA1*05 PCR assay showed good genotyping performance correlating 100% with the routinely used heterogenous reference assay. 3) To study the suitability of the complementation probe method for direct measurement of the target organism, e.g., in the culture media, the complementation probes were applied to amplificationfree closed-tube bacteriophage quantification by measuring M13 bacteriophage ssDNA. A low picomolar bacteriophage concentration was detected in a rapid 20- minute assay. The assay provides a quick and reliable alternative to the commonly used and relatively unreliable UV-photometry and time-consuming culture based bacteriophage detection methods and indicates that the method could also be used for direct measurement of other micro-organisms. The complementation probe PCR method has a low background signal level leading to a high signal-to-background ratio and relatively sensitive nucleic acid detection. The method is compatible with simple sample preparation and it was shown to tolerate residues of urine, blood, bacteria and bacterial culture media. The common trend in nucleic acid diagnostics is to create easy-to-use assays suitable for rapid near patient analysis. The complementation probe PCR assays with a brief sample preparation should be relatively easy to automate and hence, would allow the development of highperformance nucleic acid amplification assays with a short overall assay time.

Utilization of steelmaking waste materials for production of calcium carbonate (CaCO3)

The steel industry produces, besides steel, also solid mineral by-products or slags, while it emits large quantities of carbon dioxide (CO2). Slags consist of various silicates and oxides which are formed in chemical reactions between the iron ore and the fluxing agents during the high temperature processing at the steel plant. Currently, these materials are recycled in the ironmaking processes, used as aggregates in construction, or landfilled as waste. The utilization rate of the steel slags can be increased by selectively extracting components from the mineral matrix. As an example, aqueous solutions of ammonium salts such as ammonium acetate, chloride and nitrate extract calcium quite selectively already at ambient temperature and pressure conditions. After the residual solids have been separated from the solution, calcium carbonate can be precipitated by feeding a CO2 flow through the solution. Precipitated calcium carbonate (PCC) is used in different applications as a filler material. Its largest consumer is the papermaking industry, which utilizes PCC because it enhances the optical properties of paper at a relatively low cost. Traditionally, PCC is manufactured from limestone, which is first calcined to calcium oxide, then slaked with water to calcium hydroxide and finally carbonated to PCC. This process emits large amounts of CO2, mainly because of the energy-intensive calcination step. This thesis presents research work on the scale-up of the above-mentioned ammonium salt based calcium extraction and carbonation method, named Slag2PCC. Extending the scope of the earlier studies, it is now shown that the parameters which mainly affect the calcium utilization efficiency are the solid-to-liquid ratio of steel slag and the ammonium salt solvent solution during extraction, the mean diameter of the slag particles, and the slag composition, especially the fractions of total calcium, silicon, vanadium and iron as well as the fraction of free calcium oxide. Regarding extraction kinetics, slag particle size, solid-to-liquid ratio and molar concentration of the solvent solution have the largest effect on the reaction rate. Solvent solution concentrations above 1 mol/L NH4Cl cause leaching of other elements besides calcium. Some of these such as iron and manganese result in solution coloring, which can be disadvantageous for the quality of the PCC product. Based on chemical composition analysis of the produced PCC samples, however, the product quality is mainly similar as in commercial products. Increasing the novelty of the work, other important parameters related to assessment of the PCC quality, such as particle size distribution and crystal morphology are studied as well. As in traditional PCC precipitation process, the ratio of calcium and carbonate ions controls the particle shape; a higher value for [Ca2+]/[CO32-] prefers precipitation of calcite polymorph, while vaterite forms when carbon species are present in excess. The third main polymorph, aragonite, is only formed at elevated temperatures, above 40-50 °C. In general, longer precipitation times cause transformation of vaterite to calcite or aragonite, but also result in particle agglomeration. The chemical equilibrium of ammonium and calcium ions and dissolved ammonia controlling the solution pH affects the particle sizes, too. Initial pH of 12-13 during the carbonation favors nonagglomerated particles with a diameter of 1 μm and smaller, while pH values of 9-10 generate more agglomerates of 10-20 μm. As a part of the research work, these findings are implemented in demonstrationscale experimental process setups. For the first time, the Slag2PCC technology is tested in scale of ~70 liters instead of laboratory scale only. Additionally, design of a setup of several hundreds of liters is discussed. For these purposes various process units such as inclined settlers and filters for solids separation, pumps and stirrers for material transfer and mixing as well as gas feeding equipment are dimensioned and developed. Overall emissions reduction of the current industrial processes and good product quality as the main targets, based on the performed partial life cycle assessment (LCA), it is most beneficial to utilize low concentration ammonium salt solutions for the Slag2PCC process. In this manner the post-treatment of the products does not require extensive use of washing and drying equipment, otherwise increasing the CO2 emissions of the process. The low solvent concentration Slag2PCC process causes negative CO2 emissions; thus, it can be seen as a carbon capture and utilization (CCU) method, which actually reduces the anthropogenic CO2 emissions compared to the alternative of not using the technology. Even if the amount of steel slag is too small for any substantial mitigation of global warming, the process can have both financial and environmental significance for individual steel manufacturers as a means to reduce the amounts of emitted CO2 and landfilled steel slag. Alternatively, it is possible to introduce the carbon dioxide directly into the mixture of steel slag and ammonium salt solution. The process would generate a 60-75% pure calcium carbonate mixture, the remaining 25-40% consisting of the residual steel slag. This calcium-rich material could be re-used in ironmaking as a fluxing agent instead of natural limestone. Even though this process option would require less process equipment compared to the Slag2PCC process, it still needs further studies regarding the practical usefulness of the products. Nevertheless, compared to several other CO2 emission reduction methods studied around the world, the within this thesis developed and studied processes have the advantage of existing markets for the produced materials, thus giving also a financial incentive for applying the technology in practice.

Early Life Intestinal Microbiota in Health and in Atopic Eczema

Decrease in microbial contacts in affluent societies is considered to lie behind the rise in allergic and other chronic inflammatory diseases during the last decades. Indeed, deviations in the intestinal microbiota composition and diversity have been associated with several diseases, such as atopic eczema. However, there is no consensus yet on what would constitute a beneficial or harmful microbiota. The aim of this thesis was to study the microbiota development in healthy infants and to characterize intestinal microbiota signatures associated with disease status and severity in infants with atopic eczema. The methodological aim was to compare and optimize methods for DNA extraction from fecal samples to be used in high-throughput microbiota analyses. It was confirmed that the most critical step in successful microbial DNA extraction from fecal samples is the mechanical cell lysis procedure. Based on this finding, an efficient semi-automated extraction process was developed that can be scaled for use in high-throughput platforms such as phylogenetic microarray used in this series of studies. By analyzing a longitudinal motherchild cohort for 3 years it was observed that the microbiota development is a gradual process, where some bacterial groups reach the degree of adult-type pattern earlier than others. During the breast-feeding period, the microbiota appeared to be relatively simple, while major diversification was found to start during the weaning process. By the age of 3 years, the child’s microbiota composition started to resemble that of an adult, but the bacterial diversity has still not reached the full diversity, indicating that the microbiota maturation extends beyond this age. In addition, at three years of age, the child’s microbiota was more similar to mother’s microbiota than to microbiota of nonrelated women.In infants with atopic eczema, a high total microbiota diversity and abundance of butyrate-producing bacteria was found to correlate with mild symptoms at 6 months. At 18 months, infants with mild eczema had significantly higher microbiota diversity and aberrant microbiota composition when compared to healthy controls at the same age. In conclusion, the comprehensive phylogenetic microarray analysis of early life microbiota shows the synergetic effect of vertical transmission and shared environment on the intestinal microbiota development. By the age of three years, the compositional development of intestinal microbiota is close to adult level, but the microbiota diversification continues beyond this age. In addition, specific microbiota signatures are associated with the existence and severity of atopic eczema and intestinal microbiota seems to have a role in alleviating the symptoms of this disease.

Kationinvaihtohartsien hapetuskestävyys

Hyvin puhdasta vettä vaativissa sovelluksissa käytettävät kationinvaihtohartsit eivät saisi vuotaa puhdistettavaan veteen mitään vieraita aineita. Todellisuudessa hartsit kuitenkin vuotavat hyvin pieniä määriä erilaisia yhdisteitä käytön aikana. Aineet, joita kationinvaihtohartsi päästää veteen, ovat osaksi hartsin polymerointireaktion aikana sen rungon sisään jääneitä yhdisteitä. Nämä voidaan suurimmaksi osaksi poistaa pesemällä hartsia. Osittain niitä syntyy myös hartsin polystyreenidivinyylibentseenirungon (PS-DVB) hapettuessa. Hapettumisen seurauksena syntyneet yhdisteet ovat pääosin orgaanisia sulfonaatteja. Tämä työ koskee ydinvoimalaitoksissa käytettäviä pulverihartseja, joita käytetään primääripiirissä kiertävän lauhdeveden puhdistukseen ja jotka joutuvat siellä alttiiksi hapettumiselle. Yleensä hapettuminen on hidasta ja se johtuu veteen liuenneesta hapesta. Hapettuminen nopeutuu huomattavasti, jos vedessä on läsnä hapettimia tai siirtymämetalli-ioneja. Tällaisia hapettimia ovat esimerkiksi vetyperoksidi, otsoni, vapaa kloori, typpihappo ja kromi. Vetyperoksidin vaikutuksesta hartsin runkoon muodostuu hydroperoksidiryhmä, jonka hajoamisesta alkaa reaktioiden sarja, joka lopulta johtaa hartsin polymeerirungon katkeamiseen. Siirtymämetalli-ionit katalysoivat peroksidien hajoamista. Tavallisimpia hapetusta katalysoivia metalli-ioneja ovat rauta ja kupari, joiden katalyyttinen aktiivisuus on suuri. Tässä työssä pyrittiin selvittämään, onko mahdollista valmistaa hartseja, jotka kestävät hapettumista paremmin kuin nykyisin käytössä olevat hartsit. Sen tutkimiseksi tehtiin kiihdytettyjä hapetuskokeita käyttäen hapettimena vetyperoksidia ilman siirtymämetalli-ioni katalyyttejä. Hapetuskokeet tehtiin kaupallisesti saatavilla hartseilla ja uusilla työtä varten syntetisoiduilla koehartseilla. Hapetuskokeiden etenemistä seurattiin mittaamalla veteen liuenneiden orgaanisten aineiden kokonaismäärää (TOC-analyysi) ja liuoksessa esiintyvien orgaanisten sulfonaattien määrää johtokykymittauksin. Saadut tulokset antoivat viitteitä siitä, että hartsin synteesiolosuhteilla voi olla suurempi vaikutus sen hapetuskestävyyteen kuin synteesissä käytetyillä raaka-aineilla.

Development of e-Service tools for customer services and processes, Case: KONE Oyj Finland

Tutkimuksen tavoitteena oli selvittää miten kehittää yrityksen nykyistä e-palvelujärjestelmää, Internet -teknologiaan perustuvaa sähköisiä kommunikaatio- ja tiedonjakojärjestelmää, yrityksen business-to-business asiakkuuksien johtamisessa. Tavoitteena oli myös luoda ehdotukset uusista e-palvelusopimusmalleista. Tutkimuksen teoriaosuudessa pyrittiin kehittämään aikaisempiin tutkimuksiin, tietokirjallisuuteen ja asiantuntijoihin perustuva viitekehysmalli. Empiirisessä osassa tutkimuksen tavoitteisiin pyrittiin haastattelemalla yrityksen asiakkaita ja henkilöstöä, sekä tarkastelemalla asiakaskontaktien nykyistä tilaa ja kehittymistä. Näiden tietojen perusteella selvitettiin e-palvelun käyttäjien tarpeita, profiilia ja valmiuksia palvelun käyttöön sekä palvelun nykyistä houkuttelevuutta. Tutkimuksen teoriaosan lähdeaineistona käytettiin kirjallisuutta, artikkeleita ja tilastoja asiakashallinnasta sekä e-palveluiden, erityisesti Internet ja verkkopalveluiden markkinoinnista, nykytilasta sekä palveluiden kehittämisestä. Lisäksi tutkittiin kirjallisuutta arvoverkostoanalyysistä, asiakkaan arvosta, informaatioteknologiasta, palvelun laadusta ja asiakastyytyväisyydestä. Tutkimuksen empiirinen osa perustuu yrityksen henkilöstöltä sekä asiakkailta haastatteluissa kerättyihin tietoihin, yrityksen ennalta keräämiin materiaaleihin sekä Taloustutkimuksen keräämiin tietoihin. Tutkimuksessa käytettiin case -menetelmää, joka oli yhdistelmä sekä kvalitatiivista että kvantitatiivista tutkimusta. Casen tarkoituksena oli testata mallin paikkansapitävyyttä ja käyttökelpoisuutta, sekä selvittää onko olemassa vielä muita tekijöitä, jotka vaikuttavat asiakkaan saamaan arvoon. Kvalitatiivinen aineisto perustuu teemahaastattelumenetelmää soveltaen haastateltuihin asiakkaisiin ja yrityksen työntekijöihin. Kvantitatiivinen tutkimus perustuu Taloustutkimuksen tutkimukseen ja yrityksen asiakaskontakteista kerättyyn tietoon. Haastatteluiden perusteella e-palvelut nähtiin hyödyllisinä ja tulevaisuudessa erittäin tärkeinä. E-palvelut nähdään yhtenä tärkeänä kanavana, perinteisten kanavien rinnalla, tehostaa business-to-business -asiakkuuksien johtamista. Tutkimuksen antamien tulosten mukaan asiakkaiden palveluun liittyvän tieto-, taito-, tarpeellisuus- ja kiinnostavuustasojen vaihtelevaisuus osoittaa selvän tarpeen eritasoisille e-palvelupaketti ratkaisuille. Tuloksista muodostettu ratkaisuehdotus käsittää neljän eri e-palvelupaketin rakentamisen asiakkaiden eri tarpeita mukaillen.

Modeling of electrolyte sorption – from phase equilibria to dynamic separation systems

In this thesis, general approach is devised to model electrolyte sorption from aqueous solutions on solid materials. Electrolyte sorption is often considered as unwanted phenomenon in ion exchange and its potential as an independent separation method has not been fully explored. The solid sorbents studied here are porous and non-porous organic or inorganic materials with or without specific functional groups attached on the solid matrix. Accordingly, the sorption mechanisms include physical adsorption, chemisorption on the functional groups and partition restricted by electrostatic or steric factors. The model is tested in four Cases Studies dealing with chelating adsorption of transition metal mixtures, physical adsorption of metal and metalloid complexes from chloride solutions, size exclusion of electrolytes in nano-porous materials and electrolyte exclusion of electrolyte/non-electrolyte mixtures. The model parameters are estimated using experimental data from equilibrium and batch kinetic measurements, and they are used to simulate actual single-column fixed-bed separations. Phase equilibrium between the solution and solid phases is described using thermodynamic Gibbs-Donnan model and various adsorption models depending on the properties of the sorbent. The 3-dimensional thermodynamic approach is used for volume sorption in gel-type ion exchangers and in nano-porous adsorbents, and satisfactory correlation is obtained provided that both mixing and exclusion effects are adequately taken into account. 2-Dimensional surface adsorption models are successfully applied to physical adsorption of complex species and to chelating adsorption of transition metal salts. In the latter case, comparison is also made with complex formation models. Results of the mass transport studies show that uptake rates even in a competitive high-affinity system can be described by constant diffusion coefficients, when the adsorbent structure and the phase equilibrium conditions are adequately included in the model. Furthermore, a simplified solution based on the linear driving force approximation and the shrinking-core model is developed for very non-linear adsorption systems. In each Case Study, the actual separation is carried out batch-wise in fixed-beds and the experimental data are simulated/correlated using the parameters derived from equilibrium and kinetic data. Good agreement between the calculated and experimental break-through curves is usually obtained indicating that the proposed approach is useful in systems, which at first sight are very different. For example, the important improvement in copper separation from concentrated zinc sulfate solution at elevated temperatures can be correctly predicted by the model. In some cases, however, re-adjustment of model parameters is needed due to e.g. high solution viscosity.

Simulointi- ja ohjausjärjestelmän kehitys siltanosturiavusteiseen automaattivarastoon

Diplomityö tehtiin Konecranes Oyj:lle, joka on nostureita valmistava ja niille kunnossapitopalveluita tarjoava suomalainen pörssiyhtiö. Työn kuluessa suunniteltiin ja toteutettiin siltanosturiavusteisiin automaattivarastoihin soveltuva simulointiohjelmisto ja varastonohjausjärjestelmä. Työssä keskityttiin pääsääntöisesti paperirullavarastoihin, mutta suunnitteluvaiheessa otettiin huomioon myös muut Konecranesin tarjontaan kuuluvat automaattivarastotyypit kuten vaakarulla ja kontti. Simulointiohjelmistolla mallinnetaan automaattivarastossa tapahtuvia liikkeitä. Käyttäjä pystyy näkemään nostureiden ja muiden varastossa olevien komponenttien liikkeet 3D- muotoisena simulaattorin käyttöliittymästä. Simulaattorin tavoitteena on helpottaa automaattivaraston suunnittelua ja nopeuttaa sen käyttöönottoa, sekä toimia myös vakuuttavana myyntityökaluna asiakaskontakteissa. Varastonohjausjärjestelmä tekee päätökset varaston tapahtumista ja ohjaa mm. nostureiden toimintaa. Diplomityön päämääränä oli perehtyä tarkasti nykyisen varastonohjausjärjestelmän toimintaan, kehittää uusi ratkaisumalli puutteiden sekä toiveiden perusteella ja lopulta osoittaa ratkaisumallin toimivuus ohjelmoimalla esittelyversio simulaattorista ja varastonohjausjärjestelmästä. Samaa varastonohjausjärjestelmää on määrä käyttää simulaattorissa ja tulevaisuudessa todellisen varaston ohjaamisessa. Asetetuista vaatimuksista johtuen järjestelmästä suunniteltiin mahdollisimman mukautuva. Työn lopputuloksena saatiin perusominaisuudet kattava 3D-simulaattori ja siihen liitetty varastonohjausjärjestelmä. Toteutuksen avulla oli mahdollista osoittaa ratkaisumallin toimivuus sekä esitellä ideaa laajamittaisemmin. Diplomityön kuluessa saatiin nykyisestä järjestelmästä kattavat tiedot ja pystyttiin määräämään suunta, kuinka kehitystyötä jatketaan.

Optimization and Measuring Techniques for Collect-and-Place Machines in Printed Circuit Board Industry

This thesis considers optimization problems arising in printed circuit board assembly. Especially, the case in which the electronic components of a single circuit board are placed using a single placement machine is studied. Although there is a large number of different placement machines, the use of collect-and-place -type gantry machines is discussed because of their flexibility and increasing popularity in the industry. Instead of solving the entire control optimization problem of a collect-andplace machine with a single application, the problem is divided into multiple subproblems because of its hard combinatorial nature. This dividing technique is called hierarchical decomposition. All the subproblems of the one PCB - one machine -context are described, classified and reviewed. The derived subproblems are then either solved with exact methods or new heuristic algorithms are developed and applied. The exact methods include, for example, a greedy algorithm and a solution based on dynamic programming. Some of the proposed heuristics contain constructive parts while others utilize local search or are based on frequency calculations. For the heuristics, it is made sure with comprehensive experimental tests that they are applicable and feasible. A number of quality functions will be proposed for evaluation and applied to the subproblems. In the experimental tests, artificially generated data from Markov-models and data from real-world PCB production are used. The thesis consists of an introduction and of five publications where the developed and used solution methods are described in their full detail. For all the problems stated in this thesis, the methods proposed are efficient enough to be used in the PCB assembly production in practice and are readily applicable in the PCB manufacturing industry.

Local Binary Patterns in Focal-Plane Processing. Analysis and Applications

Feature extraction is the part of pattern recognition, where the sensor data is transformed into a more suitable form for the machine to interpret. The purpose of this step is also to reduce the amount of information passed to the next stages of the system, and to preserve the essential information in the view of discriminating the data into different classes. For instance, in the case of image analysis the actual image intensities are vulnerable to various environmental effects, such as lighting changes and the feature extraction can be used as means for detecting features, which are invariant to certain types of illumination changes. Finally, classification tries to make decisions based on the previously transformed data. The main focus of this thesis is on developing new methods for the embedded feature extraction based on local non-parametric image descriptors. Also, feature analysis is carried out for the selected image features. Low-level Local Binary Pattern (LBP) based features are in a main role in the analysis. In the embedded domain, the pattern recognition system must usually meet strict performance constraints, such as high speed, compact size and low power consumption. The characteristics of the final system can be seen as a trade-off between these metrics, which is largely affected by the decisions made during the implementation phase. The implementation alternatives of the LBP based feature extraction are explored in the embedded domain in the context of focal-plane vision processors. In particular, the thesis demonstrates the LBP extraction with MIPA4k massively parallel focal-plane processor IC. Also higher level processing is incorporated to this framework, by means of a framework for implementing a single chip face recognition system. Furthermore, a new method for determining optical flow based on LBPs, designed in particular to the embedded domain is presented. Inspired by some of the principles observed through the feature analysis of the Local Binary Patterns, an extension to the well known non-parametric rank transform is proposed, and its performance is evaluated in face recognition experiments with a standard dataset. Finally, an a priori model where the LBPs are seen as combinations of n-tuples is also presented

Electromagnetic and thermal design of a multilevel converter with high power density and reliability

Electric energy demand has been growing constantly as the global population increases. To avoid electric energy shortage, renewable energy sources and energy conservation are emphasized all over the world. The role of power electronics in energy saving and development of renewable energy systems is significant. Power electronics is applied in wind, solar, fuel cell, and micro turbine energy systems for the energy conversion and control. The use of power electronics introduces an energy saving potential in such applications as motors, lighting, home appliances, and consumer electronics. Despite the advantages of power converters, their penetration into the market requires that they have a set of characteristics such as high reliability and power density, cost effectiveness, and low weight, which are dictated by the emerging applications. In association with the increasing requirements, the design of the power converter is becoming more complicated, and thus, a multidisciplinary approach to the modelling of the converter is required. In this doctoral dissertation, methods and models are developed for the design of a multilevel power converter and the analysis of the related electromagnetic, thermal, and reliability issues. The focus is on the design of the main circuit. The electromagnetic model of the laminated busbar system and the IGBT modules is established with the aim of minimizing the stray inductance of the commutation loops that degrade the converter power capability. The circular busbar system is proposed to achieve equal current sharing among parallel-connected devices and implemented in the non-destructive test set-up. In addition to the electromagnetic model, a thermal model of the laminated busbar system is developed based on a lumped parameter thermal model. The temperature and temperature-dependent power losses of the busbars are estimated by the proposed algorithm. The Joule losses produced by non-sinusoidal currents flowing through the busbars in the converter are estimated taking into account the skin and proximity effects, which have a strong influence on the AC resistance of the busbars. The lifetime estimation algorithm was implemented to investigate the influence of the cooling solution on the reliability of the IGBT modules. As efficient cooling solutions have a low thermal inertia, they cause excessive temperature cycling of the IGBTs. Thus, a reliability analysis is required when selecting the cooling solutions for a particular application. The control of the cooling solution based on the use of a heat flux sensor is proposed to reduce the amplitude of the temperature cycles. The developed methods and models are verified experimentally by a laboratory prototype.

Spectrally Tuned Lanthanide Photoluminescence for Point-of-Care Testing

Point-of-care (POC) –diagnostics is a field with rapidly growing market share. As these applications become more widely used, there is an increasing pressure to improve their performance to match the one of a central laboratory tests. Lanthanide luminescence has been widely utilized in diagnostics because of the numerous advantages gained by the utilization of time-resolved or anti-Stokes detection. So far the use of lanthanide labels in POC has been scarce due to limitations set by the instrumentation required for their detection and the shortcomings, e.g. low brightness, of these labels. Along with the advances in the research of lanthanide luminescence, and in the field of semiconductors, these materials are becoming a feasible alternative for the signal generation also in the future POC assays. The aim of this thesis was to explore ways of utilizing time-resolved detection or anti-Stokes detection in POC applications. The long-lived fluorescence for the time-resolved measurement can be produced with lanthanide chelates. The ultraviolet (UV) excitation required by these chelates is cumbersome to produce with POC compatible fluorescence readers. In this thesis the use of a novel light-harvesting ligand was studied. This molecule can be used to excite Eu(III)-ions at wavelengths extending up to visible part of the spectrum. An enhancement solution based on this ligand showed a good performance in a proof-of-concept -bioaffinity assay and produced a bright signal upon 365 nm excitation thanks to the high molar absorptivity of the chelate. These features are crucial when developing miniaturized readers for the time-resolved detection of fluorescence. Upconverting phosphors (UCPs) were studied as an internal light source in glucose-sensing dry chemistry test strips and ways of utilizing their various emission wavelengths and near-infrared excitation were explored. The use of nanosized NaYF :Yb3+,Tm3+-particles enabled the replacement of an external UV-light source with a NIR-laser and gave an additional degree of freedom in the optical setup of the detector instrument. The new method enabled a blood glucose measurement with results comparable to a current standard method of measuring reflectance. Microsized visible emitting UCPs were used in a similar manner, but with a broad absorbing indicator compound filtering the excitation and emission wavelengths of the UCP. This approach resulted in a novel way of benefitting from the non-linear relationship between the excitation power and emission intensity of the UCPs, and enabled the amplification of the signal response from the indicator dye.

Medication competence of nursing students in Finland

Lääkehoidon turvallinen toteuttaminen edellyttää sairaanhoitajalta hyvää lääkehoidon osaamisperustaa. Sairaanhoitajakoulutuksen tehtävänä on mahdollistaa tämän osaamisen kehittyminen. Kansainvälisissä tutkimuksissa on kuitenkin osoitettu, että lääkehoidon opetuksen laajuudessa, sisällössä ja toteutuksessa on vaihtelevuutta. Aikaisemmissa tutkimuksissa on raportoitu myös puutteita lääkehoidon osaamisessa sekä sairaanhoitajilla että sairaanhoitajaopiskelijoilla. Koulutuksen ja lääkehoidon osaamisen kehittämiseksi lääkehoidon opetuksen ja sairaanhoitajaopiskelijoiden lääkehoidon osaamisen monipuolinen arviointi ja osaamista selittävien tekijöiden tarkastelu on tarpeen. Tämän tutkimuksen tarkoituksena oli i) arvioida lääkehoidon opetusta suomalaisessa sairaanhoitajakoulutuksessa, ii) arvioida sairaanhoitajaopiskelijoiden lääkehoidon osaamista sekä iii) tunnistaa sairaanhoitajaopiskelijan lääkehoidon osaamiseen yhteydessä olevat tekijät. Tutkimus toteutettiin kolmessa vaiheessa. Ensimmäisessä vaiheessa kahden integroidun kirjallisuuskatsauksen kautta määriteltiin tutkimuksen kohteena oleva sairaanhoitajan lääkehoidon osaaminen ja aiemmin tunnistetut sairaanhoitajaopiskelijan lääkehoidon osaamiseen yhteydessä olevat tekijät. Toisessa vaiheessa toteutettiin valtakunnallinen lääkehoidon opetukseen liittyvä kysely hoitotyön koulutusohjelmasta vastaaville koulutuspäälliköille (n=22) ja opettajille (n=136). Tutkimuksen kolmannessa vaiheessa opintojensa alku‐ (n=328) ja loppuvaiheessa olevien sairaanhoitajaopiskelijoiden (n=338) lääkehoidon osaaminen arvioitiin ja osaamiseen yhteydessä olevat tekijät tunnistettiin. Aineistojen analyysissä käytettiin pääosin tilastollisia menetelmiä. Tulosten perusteella lääkehoidon opetuksen laajuus vaihteli eri ammattikorkeakouluissa, mutta opetuksen sisältö oli kuitenkin monipuolista. Lisää huomiota tulisi kiinnittää lääkehoidon teoreettiseen perustaan ja itsehoitoon sekä lääkehoidon ohjaukseen liittyviin sisältöalueisiin. Opiskelijoiden lääkehoidon osaamista arvioitiin säännöllisesti kaikissa ammattikorkeakouluissa. Sairaanhoitajaopiskelijan lääkehoidon osaamista arvioitiin tutkimuksessa tietotestillä, lääkelaskentatehtävillä ja lyhyiden potilastapausten ratkaisemisen avulla. Lääkehoidon osaamiseen yhteydessä olevia tekijöitä tarkasteltiin kolmesta näkökulmasta: 1) yksilölliset tekijät, 2) kliiniseen oppimisympäristöön ja 3) ammattikorkeakouluun liittyvät tekijät. Lääkehoidon teoreettista osaamista arvioivassa tietotestissä opiskelijat vastasivat keskimäärin 72 prosenttiin kysymyksistä täysin oikein; lääkelaskuista täysin oikein oli 74 % ja potilastapauksissa 57 % valitsi parhaan mahdollisen toimintatavan. Tulosten perusteella sairaanhoitajaopiskelijan osaamista selittivät eniten yksilölliset tekijät. Lääkehoidon osaamiseen yhteydessä olevien tekijöiden välillä oli eroa opintojen alussa ja lopussa. Opintojen alkuvaiheessa opiskelijan aikaisempi opintomenestys oli yhteydessä lääkehoidon osaamiseen, kun taas opintojen loppuvaiheessa siihen olivat yhteydessä opiskelijan kyky itseohjautuvaan oppimiseen sekä opiskelumotivaatio. Johtopäätöksenä voidaan todeta tutkimuksen tulosten olevan samansuuntaisia kuin aikaisemmissa tutkimuksissa. Lääkehoidon opetuksen laajuus vaihtelee opetussuunnitelmatasolla, mutta täsmällinen arviointi on vaikeaa opetuksen sisältöjen integroimisen takia. Sairaanhoitajaopiskelijoiden lääkehoidon osaaminen oli hieman parempaa kuin aikaisemmissa tutkimuksissa, mutta osaamisessa on edelleen puutteita. Lääkehoidon opetuksen ja osaamisen kehittäminen edellyttää kansallista ja kansainvälistä tutkimus‐ ja kehittämisyhteistyötä. Tutkimuksen tulokset tukevat lääkehoidon opetuksen sekä osaamisen tutkimusta ja kehittämistä.

The Role of Surfactant Properties of Extractants in Hydrometallurgical LiquidLiquid Extraction Processes

The amphiphilic nature of metal extractants causes the formation of micelles and other microscopic aggregates when in contact with water and an organic diluent. These phenomena and their effects on metal extraction were studied using carboxylic acid (Versatic 10) and organophosphorus acid (Cyanex 272) based extractants. Special emphasis was laid on the study of phase behaviour in a pre neutralisation stage when the extractant is transformed to a sodium or ammonium salt form. The pre neutralised extractants were used to extract nickel and to separate cobalt and nickel. Phase diagrams corresponding to the pre neutralisation stage in a metal extraction process were determined. The maximal solubilisation of the components in the system water(NH3)/extractant/isooctane takes place when the molar ratio between the ammonia salt form and the free form of the extractant is 0.5 for the carboxylic acid and 1 for the organophosphorus acid extractant. These values correspond to the complex stoichiometry of NH4A•HA and NIi4A, respectively. When such a solution is contacted with water a microemulsion is formed. If the aqueous phase contains also metal ions (e.g. Ni²+), complexation will take place on the microscopic interface of the micellar aggregates. Experimental evidence showing that the initial stage of nickel extraction with pre neutralised Versatic 10 is a fast pseudohomogeneous reaction was obtained. About 90% of the metal were extracted in the first 15 s after the initial contact. For nickel extraction with pre neutralised Versatic 10 it was found that the highest metal loading and the lowest residual ammonia and water contents in the organic phase are achieved when the feeds are balanced so that the stoichiometry is 2NH4+(org) = Nit2+(aq). In the case of Co/Ni separation using pre neutralised Cyanex 272 the highest separation is achieved when the Co/extractant molar ratio in the feeds is 1 : 4 and at the same time the optimal degree of neutralisation of the Cyanex 272 is about 50%. The adsorption of the extractants on solid surfaces may cause accumulation of solid fine particles at the interface between the aqueous and organic phases in metal extraction processes. Copper extraction processes are known to suffer of this problem. Experiments were carried out using model silica and mica particles. It was found that high copper loading, aromacity of the diluent, modification agents and the presence of aqueous phase decrease the adsorption of the hydroxyoxime on silica surfaces.

Reactions of Chlorambucil and its main metabolite, Phenylacetic Acid Mustard, with 2’-deoxyribonucleosides and Calf Thymus DNA

Chlorambucil is an anticancer agent used in the treatment of a variety of cancers, especially in chronic lymphocytic leukemia, and autoimmune diseases. Nevertheless, chlorambucil is potentially mutagenic, teratogenic and carcinogenic. The high antitumor activity and high toxicity of chlorambucil and its main metabolite, phenylacetic acid mustard, to normal tissues have been known for a long time. Despite this, no detailed chemical data on their reactions with biomolecules in aqueous media have been available. The aim of the work described in this thesis was to analyze reactions of chlorambucil with 2’-deoxyribonucleosides and calf thymus DNA in aqueous buffered solution, at physiological pH, and to identify and characterize all adducts by using modern analyzing methods. Our research was also focused on the reactions of phenylacetic acid mustard with 2’-deoxynucleosides under similar conditions. A review of the literature consisting of general background of nucleic acids, alkylating agents and ultraviolet spectroscopy used to identify the purine and pyrimidine nucleosides, as well as the results from experimental work are presented and discussed in this doctoral thesis.