Europe’s largest chrome deposit is hosted by the 2.44 Ga Kemi ultramafic layered intrusion. The lower half of the intrusion consists of peridotites, pyroxenites and chromitite layers while the upper half consists of websterites, gabbronorites and leucogabbros. The mafic minerals of the lower and upper parts of the intrusion are altered to serpentine, chlorite, talc, amphiboles and carbonates. However, the original mineralogy is still preserved in the middle part of the intrusion. Earlier work on the Kemi intrusion concentrated mainly on the economically important chromitite layers and suggested that these layers were formed through contamination of a single pulse of primitive magma by underlying Archaean basement crustal material. The broad variations of the major element concentrations reflect variations in the mode of the Kemi rocks. The petrology, which shows olivine- and orthopyroxene-dominated rocks in the lower portion of the intrusion to plagioclase- and clinopyroxene-dominated rocks in the upper portion, shows a gross consistency with a fractional crystallization process.The incompatible elements are relatively enriched in the lower portion of the intrusion which is not consistent with a broad fractional crystallization process. These variations suggest that the ultramafic portion of the KemiIntrusion is relatively enriched in trapped liquid compared to the mafic portion.ε2.44 Nd values ranges from +4 (consistent with depleted mantle source) to -10 (indicating a contribution from Archaean crust). The lower peridotites, pyroxenites and websterites have ε2.44 Nd values ranging between depleted mantle signatures and -2, whereas the gabbroic cumulates have ε2.44 Nd values which cover a range from around -5 to -10. Nd isotopic variation in the lower part of the profile is punctuated by distinct spikes to lower ε2.44 Nd corresponding to the chromitite horizons. Both the lower and upper portions of the Kemi Intrusion show enrichment of LREEC1 relative to HREEC1. The LREEC1 enriched values start to increase markedly from about the 1000 meter mark and continue to increase in value towards the roof of the intrusion.The main enrichment of PGE (ΣPPGE = 55 to 148 ppb) occurs approximately 90 to 160 m above the basal contact, beginning within andcontinuing above the main chromitite ore horizon. The mantle-normalized PGE abundances of the main chromitite horizon and the peridotites and pyroxenites below it show enrichment of IPGEPM (Os + Ir + Ru) relative to PPGEPM (Rh + Pd + Pt). In contrast, the overlying rocks are characterised by enrichment of PPGEPM relative to IPGEPM. These PGE-patterns suggest the influence of two distinct controlling processes above and below the main chromitite reef.The isotopic data are consistent with the initial introduction of multiple pulses of depleted mantle-derived magma crystallising olivine and pyroxene. Before the parent magma was fed into the Kemi magma chamber, it underwent crustal contamination and assimilation in a staging chamber within the lower crust. Some of these pulses were “critically crustally contaminated”, inducing chromite saturation and precipitation. The modelling also predicts minor in-situ contamination of the parent magma in the Kemi chamber with its wall and roof rocks. Above the main chromitite layer (about 160 m above the basal contact), the chromite content decreases and the PPGEPM/IPGEPM values increase which is consistent with scavenging of the IPGE into the lowermost layers and/or evolving magma compositions. Above 1000 m, the isotopic and REE data indicate a new magma pulse which has also been extensively contaminated in the staging magma chamber before emplacement into the Kemi magma chamber. The contamination in the staging magma chamber increased which is reflected in a progressively larger crustal component towards the top of the Kemi Intrusion

Solid state 1H, 31P and 27Al Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) was used in studies of surface species formed on a synthetic fluorapatite in aqueous suspensions at different pH with or without ions or ion complexes of iron or aluminium in the suspension. Different sites related to the PO43- ions at the mineral surface were suggested, POx, POxH and POxH2. Also, three sites formed of Ca2+, H+ and OH- ions at the fluorapatite surface CaOH2+, CaOH and Ca(OH) 2- were suggested. Both single-pulse and cross polarization MAS NMR experiments were used to measure the 1H, 31P and 27Al isotropic chemical shifts. In the 1H to 31P cross polarization experiments the contact time was varied in order to differentiate the resonance liners corresponding to different surface sites from the resonance lines assigned to the PO43- ions in the crystal structure of fluorapatite. In the solid state dipole-dipole recoupling MAS NMR experiments the sequence XY8-DRAMA was used in studies of distances between O,O'- dialkyldithiophosphates adsorbed on synthetic galena (PbS). The sequence was tested experimentally and gave highest double-quantum excitation efficiency of the tested dipole-dipole recoupling sequences tested at the spinning frequency 4.2 kHz. A new sequence IRS-DRAMA was derived analytically and showed high double quantum excitation efficiency in a broad interval of the 31P resonance frequencies at the spinning frequency 2.1 kHz. / Godkänd; 2006; 20061205 (haneit)

In sulphide mineral flotation, a sufficient hydrophobicity of the mineral surfaces is obtained by the adsorption of collector chemicals at the metal sulphide/aqueous interface. This surface alteration is of fundamental and applied interest. In this thesis, attenuated total reflection infrared spectroscopy has been used to monitor the adsorption kinetics and the orientation of heptyl xanthate when adsorbed onto three solid surfaces - germanium, zinc sulphide and lead sulphide in-situ. The Chemical Bath Deposition method has been used to deposit metal sulphides onto germanium internal reflection elements, and verified as capable in synthesizing metal sulphide surfaces for adsorption studies recovering information about surface reactions at metal sulphide/solution interfaces. In the study of surface reactions the substrate is of great importance, implying that the chemistry of the surface has to be well characterised. This work has utilized X-ray photoelectron spectroscopy in the characterisation of the different surfaces. The adsorption kinetics has been followed to monitor the adsorption equilibria at different concentrations. In the case of heptyl xanthate adsorbed at the zinc sulphide/aqueous interface, an adsorption isotherm has been calculated from the equilibrium data. On the assumption that the adsorption step was rate controlling a pseudo-first order equation was derived and adsorption rate data, in all the three studied systems, tested according to this equation. In addition, an orientation study of the heptyl xanthate molecule at the different interfaces was performed, which requires polarised infrared light. Density Functional calculations of a free heptyl xanthate molecule, and a heptyl xanthate molecule adsorbed on a pure Ge(111) were utilized to get more information about the in-situ adsorption of heptyl xanthate on a germanium surface. The important vibration bands were assigned to different vibrations, and the theoretical infrared spectra were compared with the experimentally analyzed spectra. This study shows the strengths of using advanced first-principle Density Functional Theory in the interpretation of real surface adsorption systems. / Godkänd; 2006; 20070314 (evan)

Polymers are of fundamental importance to our society and can befound in many different products. Block copolymers are polymerswhich are divided up into distinct blocks of two or more differentmonomers. Block copolymers with regions of difference in polarityare capable of self assembling into ordered systems. These systemscan be tailored to be used for different purposes such as templatesfor material synthesis or drug delivery vehicles. The objective ofthis study was to investigate how different methods of preparing asample affect the micellar structures for the systems poly(2-ethylhexyl methacrylate) (PEHMA) - quaternized poly(dimethylaminoethyl methacrylate) (qPDMAEMA) and poly(2-ethyl-hexylmethacrylate) (PEHMA)- poly(methacrylic acid)(PMAA). The parametersstudied were choice of cosolvent and order of mixing, i.e. mixingwater with polymer solution or polymer solution with water. Thestability over time of the micellar structures were studied as wellas the Zetapotential and adsorption to model silica surfaces. Theresults showed that using different cosolvents yielded a differencein size but not in micelle stability over time. The investigationalso showed that preparing the sample by adding polymer solution towater, versus adding water to polymer solution, yielded nosignificant difference in polymer size or stability. However as thestudy was done in small volumes the concentration gradient producedduring the two methods may not differ that much and using largersample volumes may produce different results. Using a triblockcopolymer over a diblock copolymer of a corresponding size yieldedvastly different results in size, stability and adsorption. Thetriblock polymer produced smaller more stable aggregates whichadsorbed quickly and the diblock copolymer produced large,polydisperse aggregates which started to aggregate after around 7days and adsorbed slowly.

No description available.

During the last 30 years a new research and technology field of organic electronic materials has grown thanks to a groundbreaking discovery made during the late 70’s. This new field is today a worldwide research effort focusing on exploring a new class of materials that also enable many new areas of electronics applications. The reason behind the success of organic electronics is the flexibility to develop materials with new functionalities via clever chemical design and the possibility to use low‐cost production techniques to manufacture devices. This thesis reports different aspects of electrochemical applications of organic electronics. We have shown that the color contrast in reflective and transmissive electrochromic displays can be almost doubled by adding an extra electrochromic polymer. The choice of electrochromic material was found to be limited by its electrochemical over‐oxidation (ECO) properties, which is one of the main degradation mechanisms found in displays. The irreversible and non‐conducting nature of over‐oxidized films encouraged us to use it in a novel patterning process in which polythiophene films can be patterned through local and controlled deactivation of the conductivity. ECO can be combined with various patterning tools such as screen printing for low‐cost roll‐to‐roll manufacturing or photolithography, which enables patterning of small features. Studies have shown that electronic conductivity contrasts beyond 107 can be achieved, which is enough for various simple electronic systems. To generate better understanding of the ECO phenomenon, the effect of pH on the over‐oxidation characteristics was studied. The results suggest that a part of the mechanism for over‐oxidation depends on the OH– concentration of the electrolyte used. Over‐oxidation has also been used in electrochemical loggers, where the temperature and time dependence of the propagation of an over‐oxidation front is used to monitor and record the temperature of a package. / Dagligen kommer vi i kontakt med olika plastmaterial. Dessa har vanligtvis mycket dålig elektrisk ledningsförmåga och används oftast som isolerande material. Det finns dock en klass av plaster som är halvledande eller ledande. Sedan upptäckten av dessa material för mer än 30 år sedan har nya material och användningsområden utvecklats och nu börjar de första produkterna baserad på organisk elektronik komma ut på marknaden. En stor fördel med de ledande plasterna är att egenskaperna kan anpassas genom att ändra den kemiska strukturen. Man kan dessutom lösa upp dem och skapa ledande bläck, som sedan kan användas i vanliga tryckmaskiner. Detta gör det möjligt att på ett enkelt och billigt sätt tillverka elektronik på liknande sätt som till exempel tidningar trycks idag. Den här avhandlingen behandlar en del av det nya området som berör elektrokemiska komponenter och några av dess tillämpningar. Fokus ligger främst på billig, tryckt elektronik. Bland annat presenteras ett sätt att fördubbla kontrasten för tryckta pappersdisplayer, ett nytt sätt att mönstra ledande plaster och elektrokemisk temperaturloggningsetikett som kan övervaka temperaturen för förpackningar under transport. Den mekanism som förstör ledningsförmågan vid höga spänningar har varit ett återkommande inslag i de studier som har genomförts här. Denna mekanism förstör komponenterna under drift men kan också användas för att ta bort ledningsförmågan som mönstringsmetod eller för att lagra information, permanent, i temperaturloggningsetiketten.

In this project, the interaction between polyethylene glycol modified (PEG-ylated) lipid nanoparticles and silica substrates was studied to find out how this interaction was affected by bulk concentration, temperature and the composition of particles. One kind of lipodisk and four kinds of PEG-ylated liposome were prepared from lipid films and characterized by quartz crystal microbalance with dissipation monitoring (QCM-D) instrument mounted with silica sensor. The detailed information of particle-silica interaction could be obtained from the raw data, frequency and dissipation values, and the adsorbed mass surface density calculated from the raw data. Lipodisks could be immobilized on the silica surface. Whether they would be rinsed away by PBS buffer was influenced by both the bulk concentration and temperature. The way of their binding could change and the changing process was affected by temperature. PEG-ylated liposomes could also be immobilized on the silica surface, and they could break and spread to form supported lipid bilayer in certain conditions, for example, the changing of temperature or the using of certain lipids. Supported lipid bilayers were created with high reproducibility in this project, which could be very useful to the future study of transmembrane proteins functions and lipodisk properties.

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No description available.

No description available.