No description available.

This master's thesis deals with deposition of cobalt nanostructures using Electron Beam Induced Depositon (EBID). The thesis firstly describes theoretical background regarding EBID. In the following experimental part, the deposition process is optimized via analysis of exposition parameters and their influence on the final shape of nanostructures. These are analyzed via Atomic Force Microscopy (AFM). Optimized exposure parameters are then applied to the deposition of functional 3-dimensional nanostrucutres. In particular, the deposition of cobalt spheres. The elemental composition is analyzed by the means of element composition using Energy-dispersive X-ray Spectroscopy (EDX) and the nanostructures of desired morphologies are studied with Magnetic Force Microscopy (MFM) and Magneto-Optical Kerr Microscope).

[pt] Neste trabalho, foi avaliada a capacidade de biossorção dos metais pesados, cobre e cobalto, utilizando como material biossorvente a biomassa bacteriana Rhodococcus opacus uma espécie microbiana de natureza não patogênica pertencente ao gênero Rhodococcus. Durante o processo de biossorção foram estudados vários parametros operacionais como: o pH da solução, a concentração de biomassa, o tempo de contato, e a concentração inicial do metal. O processo de avaliação feita em relação ao pH indicou uma melhor remoção no valor de pH 6 para o Cobre e valor de pH 7 para o Cobalto. Com o pH estabelecido estudou-se as concentrações iniciais das espécies metálicas na faixa de 5 a 200 mg.L-1 Sendo obtido um melhor resultado com a concentração inicial 5 mg.L-1 para o metal cobalto e 15 mg.L-1 para o metal cobre. Logo em seguida foi avaliada a concentração inicial de biomassa numa faixa de 0,5 g.L-1 a 3,5 g.L-1 sendo a melhor porcentagem de remoção durante a concentração de biomassa de 3 g.L-1. Paralelamente foi avaliada a eficiência do processo de biossorção, após a realização de um pré-tratamento na biomassa com hidróxido de sódio 0,1M. Os resultados foram mostrados em gráficos de porcentagem de remoção e captação. Os dados correspondentes à capacidade de captação do R. opacus em função da concentração dos íons metálicos foram bem ajustados ao modelo da isoterma de Langmuir obtendo-se um R2 de 0,9986 para o Co2+ e 0,9783 para o Cu2+.Em relação ao tempo de adsorção verificou-se uma rápida adsorção dada em 1 minuto de contacto da biomassa com íon metálico, na qual ajustou ao modelo cinético de pseudo segunda ordem. As características da superfície do micro-organismo e os possíveis mecanismos de interação envolvidos na biossorção dos metais pesados pela biomassa bacteriana R. opacus, foram avaliadas com base em medições de potencial zeta, análise por espectrometria no infravermelho e análise de micrografias obtidas no microscópio eletrônico de varredura (MEV). / [en] In this study, was evaluated the biosorption capacity of heavy metals, copper and cobalt, using a bacterial biomass Rhodococcus opacus as biosorbent microbial a species of non-pathogenic nature of the genus Rhodococcus. During the process of biosorption were avaliated various operating prametros as: The pH of the solution, biomass concentration, contact time and initial metal concentration. The process of evaluation made in relation to the pH indicated a better removal at pH 6 and pH 7 for Coper and Cobalt. With the established pH were avaliated the initial concentrations of metal species in the range from 500 to 200 mg.L-1 after were evaluated the initial biomass concentration from 0.5 to 3.5g.L-1 being the best percentage of removal occurring in the biomass concentration of 3g.L-1. In parallel were evaluated the efficiency of the biosorption process after the completion of a pre-treatment with sodium hydroxide 0.1M The results were shown in graphs of percentage removal and uptake. The corresponding data to the uptake capacity of R. opacus depending on the concentration of metal ions were well fitted to the model of the Langmuir isotherm to yield an R2 of 0.9986 and 0.9783 for metals copper and cobalt. Regarding the adsorption time there was a rapid adsorption in which we indicated a kinetic model of pseudo second order. The surface characteristics of microorganisms and the possible interaction mechanisms involved in heavy metal sorption by R.opacus were evaluated based on measurements of zeta potential, analysis by infrared spectrometry and analysis in a scanning electron microscope (SEM).

Cancer is a leading case of mortality worldwide. Governments spent multibillion expenses on treatment and palliative care of diseased people. Despite these generous funding and intensive research with aim to find a cure or efficient treatment for cancer, until now there is a lack in selective cancer management strategies. Conventional treatment strategies for cancer, such as surgery, cytotoxic chemotherapy, radiation therapy, hormone therapy don’t have selectivity toward cancer – the property of discrimination of healthy organs and tissues from the diseased site. Chemotherapy is very challenging as the difference between effective and lethal doses is very minuscule in most cases. Moreover, devastating side effects dramatically changes the quality of life for cancer patients. To address these issues two main strategies are intensively utilized in chemistry: (I) the design and synthesis of novel anticancer organic compounds with higher selectivity and low toxicity profiles and the second, design and preparation of biocompatible nanocarriers for imaging and anticancer compound selective delivery nanomedicine. The following dissertation combines the above two strategies as bellows: First project is related to the design and synthetic route development toward novel nature-inspired group of heterocyclic compounds – iso-Phidianidines. The second project focused on design, preparation and evaluation of hybrid theranostics (therapeutic and diagnostic in a single entity). Chapter 1 is a general background review of the major topics that will be discussed in this dissertation. The first efficient and high-yielding synthetic route toward iso-phidianidines, containing regioisomeric form of 1,2,4-oxadiazole linked to the indole via methylene bridge is reported in Chapter 2. In vitro test of the synthesized library of iso-phidianidines revealed micromolar range of cytotoxicity toward human cervical cancer cell line. Structure activity relationship revealed the importance of presence of monosubsituted amine in 3 position of oxadiazole to maintain activity. Moreover, gradual increase of activity was detected in increasing of the length of the diamine. Polyamine (spermidine) side chain demonstrated strongest anticancer activity, identified as lead compound and may be studied further as a good candidate for cervical cancer treatment. Finally, the remaining high activity of amino-terminated iso-phidianidines demonstrated that presence of guanidine group in termini is not necessary for high cytotoxicity. The second part of this dissertation (Chapter 3) discusses the rational design, wet protocol synthesis and complete characterization of the novel hybrid material – polydopamine coated iron-cobalt nanocubes (PDFCs). This material was loaded with anticancer model drug doxorubicin in one step procedure (PDFC-DOX) and the resulting drug-delivery vehicle was found to be successfully internalized by cervical cancer cells. The cytotoxicity test demonstrated inhibition of 50% of the cells at the concentration of 30μg/ml for PDFC-DOX. Moreover, the release was highly attenuated and pH-sensitive in acidic range. PDFC was also modified with fluorescein leading to green fluorescent nanoparticles PDFC-FITC, which demonstrated excellent intracellular molecular imaging property. PDFCs with one of the highest magnetic saturation among the materials used in biomedicine (226 emu/g based on core) showed the absence of any cytotoxicity in vitro and excellent MRI contrasting property (r2=186.44 mMs-1, higher than commercial contrast agents Ferridex® and Clio®), both in vitro and in vivo on mice. They were cleared out from the mice bodies in month without affecting their health. Due to the high density of core (8.3 g/cm3) they demonstrated ability to be contrast materials also for X-Ray CT diagnostic modality, increasing the tumor detection and visualization probability in combination with MRI. In addition to it’s diagnostic and drug-delivery modalities, PDFC was evaluated also for microwave-induced cytotoxicity as a novel concept in cancer treatment. As low as 10 μg/ml concentration of PDFCs in human cervical cancer cells caused extensive death above 73% upon exposure to 2,45 GHz of microwaves for one minute. Laser irradiation (808 nm, 15 minutes) of cancer cells with internalized PDFCs caused cell death above 60%. The specific absorption rate of PDFCs at 470 MHz frequency and 20 mT of the alternating magnetic field power was 180 W/g, which is nearly 100 W higher than for commercial nanoparticles (Ferridex®).

Zinkgruvan is a stratiform Zn-Pb-Ag deposit located in the Bergslagen ore district in south central Sweden. Elevated concentrations of cobalt have been detected in zinc ore from the mine. Cobalt is one of EU’s critical raw materials, since cobalt is mainly mined in politically unstable countries like Congo and is an important metal needed in batteries for modern technology, e.g., electrical cars. However, elevated contents of cobalt can also cause problems during smelting of zinc ore and lower the value of zinc concentrates. Knowledge of the mineralogical deportment of cobalt is in this context critical, since accessory cobalt minerals could potentially be separated from zinc concentrates, whereas lattice-bound cobalt in sphalerite will follow the latter throughout the processing chain. In this study, the mineralogical distribution in zinc ore from three different main areas of Zinkgruvan (Knalla, Nygruvan and Westfield) has been investigated using optical microscopy, whole rock lithogeochemistry, Scanning Electron Microscope (SEM), Electron Microprobe Analysis (EMPA), Quantitative Target Mineralogy (QanTmin) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). The different datasets have been integrated in order to provide quantitative data on cobalt deportment in the samples, and for defining geochemical proxies that can be used to predict the cobalt deportment using only whole rock assay data. For the majority of the samples of this study, the cobalt content in sphalerite is higher than what has been reported in earlier studies of Zinkgruvan and are among the highest globally. In addition, this study provides the first account of high levels of lattice-bound cobalt in pyrrhotite at Zinkgruvan, for some samples being even higher than in sphalerite. Thus, the pyrrhotite could also potentially be separated from the zinc concentrate in order to dispose of some of the cobalt in the samples.  However, for the samples on which cobalt deportment calculations have been made, the results of the calculations suggest that for 50% of the samples most of the whole rock cobalt is lattice-bound to sphalerite, which is by far the predominant mineral in the zinc ore. For the remaining 50% of the samples most of the whole rock cobalt is bound to the cobalt mineral safflorite, which locally forms an important accessory mineral. No sample has the majority of the whole rock cobalt in pyrrhotite, reflecting the generally minor contents of this mineral in the zinc ore. In general, there is more lattice-bound cobalt in pyrrhotite and sphalerite in samples from Westfield and more cobalt bound to cobalt minerals in samples from Knalla. Samples from Nygruvan have very low whole rock cobalt contents altogether and contain no cobalt minerals. These spatial variations support ore genetic zonation models presented by earlier studies, with increasing Zn/Pb ratios and decreasing cobalt content in zinc ore from proximal to distal, in relation to an old hydrothermal vent zone at Knalla. However, the high cobalt and cadmium contents found at Westfield could imply that the vent zone might be more widespread than assumed by earlier studies. / Zinkgruvan är en stratiform Zn-Pb-Ag-malmförekomst som ligger i malmdistriktet Bergslagen i södra Sverige. Förhöjda koncentrationer av kobolt har upptäckts i zinkmalmen från gruvan. Kobolt är en av EU:s kritiska råmaterial eftersom kobolt främst bryts i politiskt instabila länder som t.ex. Kongo och eftersom det är en viktig metall som behövs i batterier för modern teknik, exempelvis elbilar. Förhöjda halter av kobolt kan dock också orsaka extra kostnader och försämrat utbyte vid zinkframställning från zinkmalm, och kan därmed sänka en zinkmalms värde. Kunskap om den mineralogiska fördelningen av kobolt i zinkmalmen är i detta fall avgörande, eftersom accessoriska koboltmineral potentiellt skulle kunna avlägsnas innan smältprocessen, till skillnad från gitterbunden kobolt i zinkblände som följer med zinken i hela utvinningsprocessen. I denna studie har den mineralogiska distributionen i zinkmalm från tre olika huvudområden i Zinkgruvan (Knalla, Nygruvan och Västra fältet) undersökts genom användning av optisk mikroskopering, geokemisk analys av bulkprover, svepelektronmikroskopi (SEM), elektronmikrosondanalys (EMPA), kvantitativ mineralogi (QanTmin) och laserablation-induktivt kopplad plasma-masspektrometri (LA-ICP-MS). De olika dataseten har integrerats för att tillhandahålla kvantitativa data för koboltfördelning i proverna och för att kunna definiera geokemiska kriterier som kan användas för att förutsäga koboltfördelningen med hjälp av endast litogeokemisk analysdata. För majoriteten av proverna i denna studie är koboltinnehållet i zinkblände högre än vad som har rapporterats i tidigare studier av Zinkgruvan, och är bland de högsta globalt. Dessutom tillhandahåller denna studie den första redogörelsen för höga nivåer av gitterbunden kobolt i magnetkis. För vissa prover är det sistnämnda till och med högre än i zinkblände. Således skulle även magnetkisen potentiellt kunna separeras från zinkkoncentratet för att bli av med en del av kobolten i proverna. För de prover där beräkningar på koboltfördelningen har gjorts visar dock resultaten av beräkningarna att för 50% av proverna förekommer merparten av bulkinnehållet av kobolt i malmen som gitterbundet i zinkblände, vilket är det överlägset dominerande mineralet i zinkmalmen. För de resterande 50% av bulkproverna är det mesta av kobolten bundet till koboltmineralet safflorit, som lokalt är ett viktigt accessoriskt mineral. Inget bulkprov har merparten av koboltinnehållet i magnetkis, vilket reflekterar det generellt lägre innehållet av detta mineral i zinkmalmen. I allmänhet finns det mer gitterbunden kobolt i magnetkis och zinkblände i bulkprover från Västra fältet och mer kobolt bundet till koboltmineral i bulkprover från Knalla. Bulkproverna från Nygruvan har väldigt lågt koboltinnehåll överlag, och innehåller inga koboltmineral. Dessa spatiala variationer stödjer malmgenetiska zoneringsmodeller presenterade i tidigare studier, med ökande Zn/Pb kvoter och minskande koboltinnehåll i zinkmalmen från proximal till distal, i relation till en fossil hydrotermal tillförselkanal i Knalla.  Det höga kobolt- och kadmiuminnehållet som detekterats i Västra fältet kan dock antyda att den hydrotermala tillförselkanalen skulle kunna vara mer utbredd än vad som antagits av tidigare studier.

The oxidation of thiols in petroleum is a subject of ongoing research, discussion and removal of sulfur is a topic of ongoing legislation. The Merox® process requires high pressures and temperatures. Novel catalysts and methods innovations are of interest. This work examines the synthesis, purification and use of sodium cobalt(II) tetrasulfophthalocyanine to oxidize ethanethiol to diethyl disulfide. Many systems using phthalocyanines carry out the oxidation reaction under basic conditions. This work oxidized ethanethiol to diethyl disulfide in dimethylformamide using cobalt tetrasulfophthalocyanine (CoTSPc) under alkali free conditions and was compared to cobalt sulfate heptahydrate, cobalt phthalocyanine (CoPc), FeTSPc and CuTSPc. The reaction was carried out in oxygen saturated DMF while stirring at 15, 25 and 40.00 °C. The amount of ethanethiol remaining over time was determined using Ellman's reagent. A simple GC method quantified the amount of diethyl disulfide. The reaction proceeded to completion within 10 min at 40.00 °C. A turn over number of 72 and frequency of 8.1 min−1 is obtained. The activation energy was approximately 32 kJ/mol. The prepared CoTSPc catalyst was most catalytic toward oxidation of ethanethiol followed by cobalt sulfate heptahydrate, CoPc, FeTSPc and CuTSPc was non-catalytic.

abstract: With the advancements in technology, it is now possible to synthesize new materials with specific microstructures, and enhanced mechanical and physical properties. One of the new class of materials are nanoscale metallic multilayers, often referred to as nanolaminates. Nanolaminates are composed of alternating, nanometer-thick layers of multiple materials (typically metals or ceramics), and exhibit very high strength, wear resistance and radiation tolerance. This thesis is focused on the fabrication and mechanical characterization of nanolaminates composed of Copper and Cobalt, two metals which are nearly immiscible across the entire composition range. The synthesis of these Cu-Co nanolaminates is performed using sputtering, a well-known and technologically relevant physical vapor deposition process. X-ray diffraction is used to characterize the microstructure of the nanolaminates. Cu-Co nanolaminates with different layer thicknesses are tested using microelectromechanical systems (MEMS) based tensile testing devices fabricated using photolithography and etching processes. The stress-strain behavior of nanolaminates with varying layer thicknesses are analysed and correlated to their microstructure. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019

No description available.

No description available.

No description available.