Influence of topography and surface chemistry on the wetting properties of TiO2-based ceramic coatings

Vätning av fasta ytor är ett viktigt fenomen i såväl naturen som i en lång rad av industriella tillämpningar. Det är allmänt känt att vätningen av en fast yta styrs av ytans kemi samt struktur. Målsättningen med avhandlingen var att studera hur kemisk heterogenitet och ytråhet på nanometernivå påverkar vätningsegenskaperna hos en fast yta. Ytorna som studerades var titandioxid-baserade kerama ytor som framställdes med hjälp av en sol-gel process. Vätningstudierna utfördes genom kontaktvinkelmätningar, vilket innebär att man mäter vinkeln som vätska/luft-gränsskiktet hos en vätskedroppe bildar mot en fast yta. Ytråheten hos materialen studerades främst genom atomkraftsmikroskopi (AFM). I AFM detekteras ytans struktur av en mycket skarp nål som skannar ytan. Resultaten i avhandlingen kunde framgångsrikt modelleras med existerande teorier för vätning av heterogena ytor.

Hule- ja suotovesien hallintajärjestelmän kehittäminen Ämmässuon nykyisellä kaatopaikalla

Työssä käsitellään hule- ja suotovesien hallintajärjestelmän kehittämistä Ämmässuon nykyisellä kaatopaikalla. Hallintajärjestelmää kehitettäessä on huomioitu ympäristölliset tekijät kuten topografia, sadanta, pinta- ja pohjavesiolosuhteet, maa- ja kallioperä sekä kaatopaikkaa ympäröivä alue. Vallitseva lainsäädäntö ja kaatopaikkaa koskevat luvat on selvitetty ennen hallintajärjestelmän kehittämisen suunnittelua. Kaatopaikkojen hule- ja suotovesien hallintajärjestelmän tärkeimpinä osina ovat olleet hule- ja suotovesien määrät ja niiden muutokset esim. kaatopaikan täyttösuunnitelman tai viimeistelysuunnitelman muutoksen vaikutuksesta. Määräarvioiden jälkeen on selvitetty vesien keräily, tasaus ja johtamistavat. Näitä osa-alueita suunniteltaessa on määritetty olemassa olevat rakenteet ja tarvittava lisärakennustarve. Myös mahdolliset poikkeustilanteet, kuten heikentynyt huleveden laatu, on huomioitu johtamisjärjestelyitä suunniteltaessa. Tämän lisäksi hallintajärjestelmään on liitetty suotoveden erillis- ja esikäsittelytarpeet sekä mahdollinen kierrättäminen takaisin jätetäyttöön paremman biohajoavuuden aikaan saamiseksi. Vesien keräilyn, virtauksen tasaamisen ja johtamisen lisäksi hallintajärjestelmään kuuluvat mittaavat ja ohjaavat automaatiojärjestelmät sekä tiedonkeräily- ja käsittelyjärjestelmät. Varsinainen mittaus- ja automaatiosuunnittelu on jätetty tämän työn ulkopuolelle. Työhön on lisäksi liitetty aikataulu- ja kustannustarkastelu. Näin on mahdollista varautua järjestelmän rakenteellisten osien toteuttamiseen sekä niistä aiheutuviin kustannuksiin

Reconstruction and analysis of surface variation using photometric stereo

In many industrial applications, accurate and fast surface reconstruction is essential for quality control. Variation in surface finishing parameters, such as surface roughness, can reflect defects in a manufacturing process, non-optimal product operational efficiency, and reduced life expectancy of the product. This thesis considers reconstruction and analysis of high-frequency variation, that is roughness, on planar surfaces. Standard roughness measures in industry are calculated from surface topography. A fast and non-contact method to obtain surface topography is to apply photometric stereo in the estimation of surface gradients and to reconstruct the surface by integrating the gradient fields. Alternatively, visual methods, such as statistical measures, fractal dimension and distance transforms, can be used to characterize surface roughness directly from gray-scale images. In this thesis, the accuracy of distance transforms, statistical measures, and fractal dimension are evaluated in the estimation of surface roughness from gray-scale images and topographies. The results are contrasted to standard industry roughness measures. In distance transforms, the key idea is that distance values calculated along a highly varying surface are greater than distances calculated along a smoother surface. Statistical measures and fractal dimension are common surface roughness measures. In the experiments, skewness and variance of brightness distribution, fractal dimension, and distance transforms exhibited strong linear correlations to standard industry roughness measures. One of the key strengths of photometric stereo method is the acquisition of higher frequency variation of surfaces. In this thesis, the reconstruction of planar high-frequency varying surfaces is studied in the presence of imaging noise and blur. Two Wiener filterbased methods are proposed of which one is optimal in the sense of surface power spectral density given the spectral properties of the imaging noise and blur. Experiments show that the proposed methods preserve the inherent high-frequency variation in the reconstructed surfaces, whereas traditional reconstruction methods typically handle incorrect measurements by smoothing, which dampens the high-frequency variation.

Hajupäästöjen tutkiminen Saint-Gobain Rakennustuotteet Oy:n Hyvinkään lasivillatehtaalla

Hajupäästöillä tarkoitetaan tavallisesti teollisen toiminnan aiheuttamia hajuaineiden päästöjä ympäristöön. Suomessa ympäristölainsäädäntö ei varsinaisesti kiellä hajuaineiden päästöjä mutta edellyttää kuitenkin, ettei niistä aiheudu merkittävää viihtyvyyshaittaa. Tässä työssä tutkittiin hajupäästöjä Saint-Gobain Rakennustuotteet Oy:n Hyvinkään lasivillatehtaalla. Tavoitteena työssä oli selvittää, mikä on tehtaan aiheuttamien päästöjen hajuvaikutus, ja mitä hajuyhdisteitä valmistusprosessissa muodostuu. Lisäksi työssä selvitettiin miten hajupäästöjä pystyttäisiin vähentämään. Työn kokeellisten tutkimusten aikana kerättiin tietoa hajun esiintymisestä valitulta tarkasteluajanjaksolta sekä mitattiin mm. tehtaan savukaasujen hajupitoisuutta ja koostumusta. Mittauksissa kaasunäytteiden hajupitoisuudeksi saatiin 170 HY/m3, joka kuvaa suhteellisen mietoa hajua. Näytteistä analysoidut haihtuvat orgaaniset yhdisteet olivat suurelta osin peräisin lasivillan valmistuksessa käytetystä sideaineesta, jota lisätään tuotteen joukkoon kuidutusvaiheessa. Ympäristöstä otetuista näytteistä ei kuitenkaan havaittu piipun yhdisteitä, mikä viittaisi siihen, että mittausjaksonaikana tehtaan päästöjen leviäminen ympäristöön on tapahtunut melko pieninä pitoisuuksina. Lisäksi on mahdollista, että ulkoilmassa yhdisteissä tapahtuu kemiallista muutuntaa ja hajontaa, jonka seurauksena yhdisteet muuttuvat. Tehtaan hajuhaitat vaikuttaisivat tutkimustulosten mukaan johtuvan savupainumaksi kutsutusta ilmiöstä. Savupainumaan vaikuttavat kaasun lämpömäärä sekä ympäristön olosuhteet ja topografia. Hajuhaittojen poistamiseksi olisi muodostuvia hajuyhdisteitä pystyttävä vähentämään 95-100 %.

Understanding the Racial Nature of Police and Immigrant Relations In Finland. The Case of Africans in Turku

The focus of this study is to examine the role of police and immigrants’ relations, as less is known about this process in the country. The studies were approached in two different ways. Firstly, an attempt was made to examine how immigrants view their encounters with the police. Secondly, the studies explored how aware the police are of immigrants’ experiences in their various encounters and interactions on the street level. An ancillary aim of the studies is to clarify, analyse and discuss how prejudice and stereotypes can be tackled, thereby contributing to the general debate about racism and discrimination for better ethnic relations in the country. The data in which this analysis was based is on a group of adults (n=88) from the total of 120 Africans questioned for the entire study (n=45) police cadets and (n=6) serving police officers from Turku. The present thesis is a compilation of five articles. A summary of each article findings follows, as the same data was used in all five studies. In the first study, a theoretical model was developed to examine the perceived knowledge of bias by immigrants resulting from race, culture and belief. This was also an attempt to explore whether this knowledge was predetermined in my attempt to classify and discuss as well as analyse the factors that may be influencing immigrants’ allegations of unfair treatment by the police in Turku. The main finding shows that in the first paper there was ignorance and naivety on the part of the police in their attitudes towards the African immigrant’s prior experiences with the police, and this may probably have resulted from stereotypes or their lack of experience as well as prior training with immigrants where these kinds of experience are rampant in the country (Egharevba, 2003 and 2004a). In exploring what leads to stereotypes, a working definition is the assumption that is prevalent among some segments of the population, including the police, that Finland is a homogenous country by employing certain conducts and behaviour towards ethnic and immigrant groups in the country. This to my understanding is stereotype. Historically this was true, but today the social topography of the country is changing and becoming even more complex. It is true that, on linguistic grounds, the country is multilingual, as there are a few recognised national minority languages (Swedish, Sami and Russian) as well as a number of immigrant languages including English. Apparently it is vital for the police to have a line of communication open when addressing the problem associated with immigrants in the country. The second paper moved a step further by examining African immigrants’ understanding of human rights as well as what human rights violation means or entails in their views as a result of their experiences with the police, both in Finland and in their country of origin. This approach became essential during the course of the study, especially when the participants were completing the questionnaire (N=88), where volunteers were solicited for a later date for an in-depth interview with the author. Many of the respondents came from countries where human rights are not well protected and seldom discussed publicly, therefore understanding their views on the subject can help to explain why some of the immigrants are sceptical about coming forward to report cases of batteries and assaults to the police, or even their experiences of being monitored in shopping malls in their new home and the reason behind their low level of trust in public authorities in Finland. The study showed that knowledge of human rights is notably low among some of the participants. The study also found that female respondents were less aware of human rights when compared with their male counterparts. This has resulted in some of the male participants focussing more on their traditional ways of thinking by not realising that they are in a new country where there is equality in sexes and lack of respect on gender terms is not condoned. The third paper focussed on the respondents’ experiences with the police in Turku and tried to explore police attitudes towards African immigrant clients, in addition to the role stereotype plays in police views of different cultures and how these views have impacted on immigrants’ views of discriminatory policing in Turku. The data is the same throughout the entire studies (n=88), except that some few participants were interviewed for the third paper thirty-five persons. The results showed that there is some bias in mass-media reports on the immigrants’ issues, due to selective portrayal of biases without much investigation being carried out before jumping to conclusions, especially when the issues at stake involve an immigrant (Egharevba, 2005a; Egharevba, 2004a and 2004b). In this vein, there was an allegation that the police are even biased while investigating cases of theft, especially if the stolen property is owned by an immigrant (Egharevba, 2006a, Egharevba, 2006b). One vital observation from the respondents’ various comments was that race has meaning in their encounters and interaction with the police in the country. This result led the author to conclude that the relation between the police and immigrants is still a challenge, as there is rampant fear and distrust towards the police by some segments of the participating respondents in the study. In the fourth paper the focus was on examining the respondents’ view of the police, with special emphasis on race and culture as well as the respondents’ perspective on police behaviour in Turku. This is because race, as it was relayed to me in the study, is a significant predictor of police perception (Egharevba, 2005a; Egharevba and Hannikianen, 2005). It is a known scientific fact that inter-group racial attitudes are the representation of group competition and perceived threat to power and status (Group-position theory). According to Blumer (1958) a sense of group threat is an essential element for the emergence of racial prejudice. Consequently, it was essential that we explored the existing relationship between the respondents and the police in order to have an understanding of this concept. The result indicates some local and international contextual issues and assumptions that were of importance tackling prejudice and discrimination as it exists within the police in the country. Moreover, we have to also remember that, for years, many of these African immigrants have been on the receiving end of unjust law enforcement in their various countries of origin, which has resulted in many of them feeling inferior and distrustful of the police even in their own country of origin. While discussing the issues of cultural difference and how it affects policing, we must also keep in mind the socio-cultural background of the participants, their level of language proficiency and educational background. The research data analysed in this study also confirmed the difficulties associated with cultural misunderstandings in interpreting issues and how these misunderstandings have affected police and immigrant relations in Finland. Finally, the fifth paper focussed on cadets’ attitudes towards African immigrants as well as serving police officers’ interaction with African clients. Secondly, the police level of awareness of African immigrants’ distrustfulness of their profession was unclear. For this reason, my questions in this fifth study examined the experiences and attitudes of police cadets and serving police officers as well as those of African immigrants in understanding how to improve this relationship in the country. The data was based on (n=88) immigrant participants, (n=45) police cadets and 6 serving police officers from the Turku police department. The result suggests that there is distrust of the police in the respondents’ interaction; this tends to have galvanised a heightened tension resulting from the lack of language proficiency (Egharevba and White, 2007; Egharevba and Hannikainen, 2005, and Egharevba, 2006b) The result also shows that the allegation of immigrants as being belittled by the police stems from the misconceptions of both parties as well as the notion of stop and search by the police in Turku. All these factors were observed to have contributed to the alleged police evasiveness and the lack of regular contact between the respondents and the police in their dealings. In other words, the police have only had job-related contact with many of the participants in the present study. The results also demonstrated the complexities caused by the low level of education among some of the African immigrants in their understanding about the Finnish culture, norms and values in the country. Thus, the framework constructed in these studies embodies diversity in national culture as well as the need for a further research study with a greater number of respondents (both from the police and immigrant/majority groups), in order to explore the different role cultures play in immigrant and majority citizens’ understanding of police work.

Mikkelin Pursialan pohjavesialueen haitta-aineet

Mikkelin talousvedestä kahden kolmasosan tullessa Pursialan pohjavesialueelta on alueen suojeleminen tärkeää. Pohjaveden laatua uhkaavat etenkin alueella sattuneet pohjavedenpilaantumistapaukset. Merkittävimmät pohjaveden pilaantumistapaukset ovat VAPO Oy:n sahan aiheuttama pohjaveden pilaantuminen kloorifenoleilla (CP) ja VR:n ratapölkkykyllästämön aiheuttama pohjaveden pilaantuminen kreosoottiöljyllä sekä Rinnekadun Nesteen aiheuttama pohjaveden pilaantuminen MTBE:llä. Alueella on tehty tutkimuksia ja kunnostuksia pilaantumiin liittyen, mutta näiden tuloksia ei ole aikaisemmin koottu yhteen. Tämän työn tavoitteena oli koota tulokset samaan aineistoon. Työssä keskityttiin kloorifenolien leviämisen tarkasteluun sen Pursialan pohjavedenottamolle muodostaman suurimman uhan vuoksi. Kallioperätietojen, maanpintatietojen ja näytetietojen pohjalta laadittiin myös pienoismalli CP-pilaantuman leviämisen kokonaiskuvan hahmottamiseksi. Työn tavoitteena oli lisäksi tehdä riskitarkastelua CP-pilaantumaan liittyen ja etsiä keinoja hallita havaittuja riskejä. Riskinhallintaan liittyen työssä tutkittiin kloorifenoleilla pilaantuneen alueen maaperä- ja kalliotietoja sekä pohjaveden laatutietoja. Pursialan pohjavedessä on runsaasti rautaa ja mangaania sekä aggressiivista hiilihappoa. Pohjaveden pH on alueella noin 6,5, lämpötila noin 7,5 ºC ja happipitoisuus noin 0,7 mg/l. Pursialan kaupunginalueen kallioperässä on havaittavissa VAPO Oy:n sahalta vedenottamolle etenevä kalliopainanne, jota pitkin CP etenee. Alueen kallioperä on kiillegneissiä, jossa on pohjois–etelä-suuntaista rakoilua. Maaperätuloksien perusteella on havaittavissa vettä hyvin johtavien maakerrosten jatkuminen koko vedenottamon ja sahan välisen matkan, mikä tarkoittaa, että CP-pitoisella pohjavedellä voi olla aiemmin oletettua nopeampikin yhteys sahalta vedenottamolle. Suurin CP-pitoisuus noin 100 000 µg/l on mitattu KY-5-altaan kohdalle asennetun M14-pohjavesiputken pohjasta. Talousvesiasetuksen raja-arvo CP:lle on 10 µg/l. Sahan ja vedenottamon puolivälissä on havaittu yli 10 000 µg/l meneviä CP-pitoisuuksia. Suurin vedenottamon kaivoista (kaivo 10) mitattu pitoisuus on 149 µg/l. Jakotukilta raakavedestä otetuissa näytteissä tai talousvedessä ei ole kuitenkaan havaittu talousvesiasetuksen ylittäviä CP-pitoisuuksia. Pienoismallin perusteella CP sijaitsee sahan alueella lähellä kallionpintaa ja hajaantuu koko pohjavesipatjaan vedenottamolle päin mentäessä. CP-mittaustuloksissa on havaittavissa pulssimaisuutta. Tämä johtuu todennäköisesti Saimaan pinnan vaihtelun seurauksena muuttuvasta rantaimeytyneen pohjaveden määrästä. Saimaan pinnan nousu näyttäisi tuloksien perusteella nostavan CP-pitoisuuksia saha-alueella ja laskevan lähellä vedenottamoa. Pohjaveden pintatietojen perusteella tehdyn tarkastelun mukaan pohjavesi voi kulkeutua sahalta vedenottamolle parhaimmillaan noin vuodessa. Työssä arvioitiin KY-5–liuoksen vuosittaiseksi käyttömääräksi noin 648–970 m3. Allassakkaa arvioitiin syntyneen yhteensä noin 10–31 m3. Pohjaveteen arvioitiin joutuneen toiminnan aikana yhteensä noin 3 000–4 000 kg CP:tä. Kloorifenolit esiintyvät pohjavedessä lähes täysin kloorifenolaatteina. Kloorifenolien hajoaminen ja muuntuminen pohjavedessä on epätodennäköistä. Käsitteellisen mallin mukaan kloorifenolipilaantuman suurimmat riskit aiheutuvat kloorifenolien mahdollisuudesta pilata Pursialan vedenottamon talousvesi. Tällä hetkellä riskejä hallitaan kloorifenolien leviämisen tarkkailulla, sahan ja vedenottamon puolivälissä sijaitsevalla koepumppauksella sekä varautumalla aktiivihiilijauheen syöttöön talousvesiprosessiin. Koepumppauksen avulla on saatu ylös tällä hetkellä noin 69 kg kloorifenoleita. Tutkimuksen perusteella suositeltavimmat riskinhallintatoimet tulevaisuudessa ovat sahalla sijaitseva kunnostuspumppaus, sahan ja vedenottamon väliin sijoittuva suojapumppaus- ja vesiverhoyhdistelmä sekä sahan rannan kautta tapahtuvan rantaimeytymisen estäminen.

Miksi etsiä kuvan ja olemisen alkuja? : miksi ei?

Kirjallisuusarvostelu

Kelvin Probe Force Microscopy (KPFM) characterization of lanthanum lutetium oxide high-k dielectric thin films

Lanthanum lutetium oxide (LaLuO3) thin films were investigated considering their perspective application for industrial microelectronics. Scanning probe microscopy (SPM) techniques permitted to visualize the surface topography and study the electric properties. This work compared both the material properties (charge behavior for samples of 6 nm and 25 nm width) and the applied SPM modes. Particularly, Kelvin probe force microscopy (KPFM) was applied to characterize local potential difference with high lateral resolution. Measurements showed the difference in morphology, chargeability and charge dissipation time for both samples. The polarity effect was detected for this material for the first time. Lateral spreading of the charged spots indicate the diffusive mechanism to be predominant in charge dissipation. This allowed to estimate the diffusion coefficient and mobility. Using simple electrostatic model it was found that charge is partly leaking into the interface oxide layer.

Paper for printed electronics and functionality

Mass-produced paper electronics (large area organic printed electronics on paper-based substrates, “throw-away electronics”) has the potential to introduce the use of flexible electronic applications in everyday life. While paper manufacturing and printing have a long history, they were not developed with electronic applications in mind. Modifications to paper substrates and printing processes are required in order to obtain working electronic devices. This should be done while maintaining the high throughput of conventional printing techniques and the low cost and recyclability of paper. An understanding of the interactions between the functional materials, the printing process and the substrate are required for successful manufacturing of advanced devices on paper. Based on the understanding, a recyclable, multilayer-coated paper-based substrate that combines adequate barrier and printability properties for printed electronics and sensor applications was developed in this work. In this multilayer structure, a thin top-coating consisting of mineral pigments is coated on top of a dispersion-coated barrier layer. The top-coating provides well-controlled sorption properties through controlled thickness and porosity, thus enabling optimizing the printability of functional materials. The penetration of ink solvents and functional materials stops at the barrier layer, which not only improves the performance of the functional material but also eliminates potential fiber swelling and de-bonding that can occur when the solvents are allowed to penetrate into the base paper. The multi-layer coated paper under consideration in the current work consists of a pre-coating and a smoothing layer on which the barrier layer is deposited. Coated fine paper may also be used directly as basepaper, ensuring a smooth base for the barrier layer. The top layer is thin and smooth consisting of mineral pigments such as kaolin, precipitated calcium carbonate, silica or blends of these. All the materials in the coating structure have been chosen in order to maintain the recyclability and sustainability of the substrate. The substrate can be coated in steps, sequentially layer by layer, which requires detailed understanding and tuning of the wetting properties and topography of the barrier layer versus the surface tension of the top-coating. A cost competitive method for industrial scale production is the curtain coating technique allowing extremely thin top-coatings to be applied simultaneously with a closed and sealed barrier layer. The understanding of the interactions between functional materials formulated and applied on paper as inks, makes it possible to create a paper-based substrate that can be used to manufacture printed electronics-based devices and sensors on paper. The multitude of functional materials and their complex interactions make it challenging to draw general conclusions in this topic area. Inevitably, the results become partially specific to the device chosen and the materials needed in its manufacturing. Based on the results, it is clear that for inks based on dissolved or small size functional materials, a barrier layer is beneficial and ensures the functionality of the printed material in a device. The required active barrier life time depends on the solvents or analytes used and their volatility. High aspect ratio mineral pigments, which create tortuous pathways and physical barriers within the barrier layer limit the penetration of solvents used in functional inks. The surface pore volume and pore size can be optimized for a given printing process and ink through a choice of pigment type and coating layer thickness. However, when manufacturing multilayer functional devices, such as transistors, which consist of several printed layers, compromises have to be made. E.g., while a thick and porous top-coating is preferable for printing of source and drain electrodes with a silver particle ink, a thinner and less absorbing surface is required to form a functional semiconducting layer. With the multilayer coating structure concept developed in this work, it was possible to make the paper substrate suitable for printed functionality. The possibility of printing functional devices, such as transistors, sensors and pixels in a roll-to-roll process on paper is demonstrated which may enable introducing paper for use in disposable “onetime use” or “throwaway” electronics and sensors, such as lab-on-strip devices for various analyses, consumer packages equipped with product quality sensors or remote tracking devices.

Characteristics of urban heat island (UHI) in a high latitude coastal city - a case study of Turku, SW Finland

The term urban heat island (UHI) refers to the common situation in which the city is warmer than its rural surroundings. In this dissertation, the local climate, and especially the UHI, of the coastal city of Turku (182,000 inh.), SW Finland, was studied in different spatial and temporal scales. The crucial aim was to sort out the urban, topographical and water body impact on temperatures at different seasons and times of the day. In addition, the impact of weather on spatiotemporal temperature differences was studied. The relative importance of environmental factors was estimated with different modelling approaches and a large number of explanatory variables with various spatial scales. The city centre is the warmest place in the Turku area. Temperature excess relative to the coldest sites, i.e. rural areas about 10 kilometers to the NE from the centre, is on average 2 °C. Occasionally, the UHI intensity can be even 10 °C. The UHI does not prevail continuously in the Turku area, but occasionally the city centre can be colder than its surroundings. Then the term urban cool island or urban cold island (UCI) is used. The UCI is most common in daytime in spring and in summer, whereas during winter the UHI prevails throughout the day. On average, the spatial temperature differences are largest in summer, whereas the single extreme values are often observed in winter. The seasonally varying sea temperature causes the shift of relatively warm areas towards the coast in autumn and inland in spring. In the long term, urban land use was concluded to be the most important factor causing spatial temperature differences in the Turku area. The impact was mainly a warming one. The impact of water bodies was emphasised in spring and autumn, when the water temperature was relatively cold and warm, respectively. The impact of topography was on average the weakest, and was seen mainly in proneness of relatively low-lying places for cold air drainage during night-time. During inversions, however, the impact of topography was emphasised, occasionally outperforming those of urban land use and water bodies.