Molecular modeling, using both ab initio and semi-empirical methods has been undertaken for a series of dirhodium complexes in order to improve the understanding of the nature of the chemical bonding in this class of homogeneous catalysts. These complexes, with carboxylamidate and carboxylate ligands, are extremely functional metal catalysts used in the synthesis of pharmaceuticals and agrochemicals. The X-ray crystallography shows anomalies in the bond angles that have potential impact on understanding the catalysis. To resolve these issues, minimum energy structures of several examples (e.g. Rh2(NHCOCH3)4, Rh2(NHCOCH3)4NC, Rh2(CO2CH3)4, Rh2(CO2CH3)4NC, Rh2(CHO2)4, and Rh2(CHO2)4NC) were calculated using Hatree-Fock and Density Functional Theory/B3LYP with the LANL2DZ ECP (Rh), and cc-pVDZ (all other atoms) basis sets.

Conventional screening of potential drug candidates through wet lab affinity experiments using libraries of thousands of modified molecules is time and resource consuming, along with the fact that it contributes to the widening time gap between the discovery of disease-causing mutations and the implementation of resulting novel treatments. It is necessary to explore whether the preliminary use of high-throughput virtual screening (HTVS) software such as PyRx will curb both the time and money spent in discovering novel treatments for diseases such as congenital heart defects (CHDs). For example, AXIN2, a protein involved in a negative feedback loop inhibiting the Wnt/β-catenin signaling pathway important for cardiogenesis, has recently been associated with CHD. The loss-of-function mutation L10F on the tankyrase-binding domain of AXIN2 has been shown to upregulate the pathway by loss of inhibition ability, leading to the accumulation of intracellular β-catenin. In a different paper, however, AXIN2 has been shown to be stabilized using XAV-939, a small-molecule drug which targets tankyrase. PyRx and VMD will be used to modify the drug in order to increase its binding affinity to AXIN2, stabilizing the protein and reinstating its inhibitory property to treat CHDs. When used in adjunction to wet lab experiments, HTVS software may decrease costs and the time required to bring a potentially life-saving treatment into use.

This research encompasses many aspects of chemical education research including curriculum and pedagogical changes to the freshman and sophomore courses. Curriculum changes included the addition of recitations to the general chemistry and organic chemistry lectures and the creation of four new classes, CHEM 1001, 1002, 3091, and 3092. The addition of recitations was not limited to but was focused on improving DFW rates for these courses. CHEM 3091 and 3092 are chemistry internship and undergraduate teaching assistant classes. These courses were necessary to offer outside internship opportunities and training for undergraduate teaching assistants, respectively. CHEM 1001 and 1002 are chemistry classes for nonscience majors. These courses were created to attempt to increase the number of nonscience major students choosing chemistry to complete their science requirement. CHEM 1001 and 1002 were courses not offered at any other university and required that the course materials and textbooks for these classes to be created from scratch without any foundation from other courses. An unforeseen consequence of the creation of these courses was the need to improve scientific communication between scientists and non-scientists and even scientist and scientist. Pedagogical work included a video intensive lecture style (VILS) for disseminating the material in the newly created CHEM 1001 and 1002 courses. For general chemistry and organic chemistry lecture, the major change was the addition of required recitation sessions for these courses. Further pedagogical changes to the organic lecture included introduction of video lectures, implementation of active learning in the lecture and graded, online homework.

<p>The increased use of biomass and recovered waste fuels in favor of fossil fuels for heat and power production is an important step towards a sustainable future. Combustion of waste fuels also offers several advantages over traditional landfilling, such as substantial volume reduction, detoxification of pathological wastes, and reduction of toxic leaches and greenhouse gas (methane) formation from landfills. However, combustion of recovered waste fuels emits more harmful trace elements than combustion of other fuels. These elements are distributed between bottom ash, fly ash and flue gas, depending on the elements partitioning and enrichment behavior. Volatilized harmful trace elements are mainly enriched in the submicron fly ash fraction. If emitted to the atmosphere, submicron particles can penetrate deep into the alveoli of the lungs, causing severe impacts on human health. Consequently, to reduce ash related problems and to control the emissions to the atmosphere, there is an increased need for understanding the physicochemical processes involved in ash transformation, including particle formation.</p><p>The objective of this thesis was to carefully and systematically study the fate of trace elements during combustion, i.e. the chemical form of the elements and the partitioning behavior, by means of chemical equilibrium model calculations, X-ray diffraction, microscopy techniques and various spectroscopy methods. The influence of some fuel additives was also analyzed. Primarily, the elements copper, chromium and arsenic were studied.</p><p>An initial review and evaluation of the content of thermodynamical data in commercial thermochemical databases used for chemical equilibrium model calculations showed that there was a significant difference in number of included phases and species between databases. Thermodynamical data also differed between databases, although in general less for condensed phases than for gaseous species. A state-of-the-art database for Cu, Cr and As was compiled and used for further chemical equilibrium model calculations. The fate of Cu, Cr and As was determined in combustion experiments on wood impregnated with copper, chromium and arsenic (CCA) in a bench scale reactor (15 kW). The results showed that global chemical equilibrium model calculations predicted the overall fate of Cu, Cr and As in bottom ash and ash particles quite well. However, compared to the experimental results the global model overpredicted the formation of refractory calcium arsenates, thus the arsenic volatilization was found to be higher then the predicted volatilization. In terms of chromium volatility, copper was found to be an important refractory element forming stable CuCrO₂(s) and CuCr₂O₄(s) that suppressed the formation of CrO₂(OH)₂(g). The retention and speciation of Cu, Cr and As in bottom ash was further determined from combustion experiments of CCA wood fuel particles in a single particle reactor. Local chemical equilibrium model calculations were performed to simulate the combustion stages of a burning CCA treated wood fuel particle: drying, devolatilization, char burning and post-combustion. The results from the work showed that a mix of global and local chemical equilibrium model calculations is needed to describe the reality and that the combustion stages are partially overlapping. The fate of harmful trace elements, including Cu, Cr and As, was finally studied in full scale (65 MW) combustion experiments. Particles from the raw flue gas emissions were sampled and analyzed. The comparison with chemical equilibrium model calculations showed that the model explained the results well, but due to lack of thermodynamic data for K₂ZnCl₄(s), the formation of this phase could not be predicted.</p>

<p>The purpose of this diploma work was to investigate the problem of insufficient fibre recovery in the dissolved air flotation-cell at the new thermomechanical pulping-line at Braviken Paper Mill. An investigation of the effect of process parameters on the removal efficiency in the micro-flotation process was undertaken.</p><p>The experiments were carried out for two setups at the Noss pilot plant with a small-scale flotation unit. Factorial design helped plan the experiments and four factors were controlled; temperature, fibre-size distribution, water quality and feed concentration. Three samples, feed, overflow and filtrate, were taken from each experiment and concentration measurements were made. The results were analyzed using the software MODDE.</p><p>The results from showed an influence from the fibre-size distribution. To see if the fibre-size distribution really had an effect on the results, follow-up experiments were carried out. These experiments showed no influence from temperature, fibre-size distribution or water quality. This concludes that none of those three factors influenced the results significantly.</p><p>Additional experiments were done to examine the influence from concentration and fibre-size distribution on the flotation efficiency and these showed an influence from the feed concentration. When increasing the feed concentration the efficiency of the flotation process decreased.</p>

<p>Nedbrytning av organiskt material är en nyckelfaktor som påverkar omvandlingar av de många grundämnen som utgör eller är associerade till just organiskt material. En stor del av nedbrytningen av akvatiskt organiskt material (OM) sker i gränsskiktet mellan sediment och vatten. Eftersom så många biogeokemiska cykler styrs av nedbrytningen av OM är det viktigt att ha kunskap om processer och påverkansfaktorer både på mikro- och makronivå. Mineraliseringshastigheten av OM är en vanligt förekommande mätparameter, men vanligtvis inkluderar mätningarna inte de naturliga processer som kan påverka nedbrytnings-hastigheterna, t.ex. fysiska krafter.</p><p>Syftet med den här studien är att studera mineraliseringshastigheten av det OM som finns naturligt i ytsediment i söt- och brackvatten när det utsätts för fysiska krafter som orsakar förändringar i redox-förhållanden, resuspension eller advektivt porvattenflöde. Fem</p><p>laborativa experiment har utförts för att belysa syftet:</p><p>Åldrat ytsediment från en sötvattens å utsattes för olika redox förhållanden där oxisk respiration, sulfatreduktion respektive metanogenes gynnades. Resultaten visade ingen skillnad i mineraliseringshastighet beroende på behandling. Detta motsäger studier utförda i marina miljöer, där anoxiska förhållanden ger en lägre mineraliseringshastighet än oxiska.</p><p>Vidare gjordes två studier på brackvattensediment där effekten av resuspension var i centrum. Den ena studien fokuserade på frekvens och varaktighet av resuspensionstiderna, den andra på olika typer av sediment. Studierna visade att väldigt korta resuspensionstider med upp till 48 timmars stillhet mellan varje resuspension ökade mineraliseringstakten med fem gånger jämfört med diffusivt utbyte, och mer än dubblerades i jämförelse med kontinuerlig resuspension eller resuspension i långa perioder. Resuspensionen under kort tid var troligen gynnande då resuspension fysiskt stör bildningen av stabila bakteriesamhällen. Mineraliseringshastigheterna i sediment som domineras av väldigt fin, fin eller medium sand visade lika hastigheter, medan grov sand visade en signifikant lägre mineraliseringshastighet. Likheterna mellan de tre första sedimenttyperna kan dock ha påverkats av tillgång på lättnedbrytbart OM då sediment och vatten hämtades in under en algblomning.</p><p>Till sist studerades effekten på mineraliseringshastigheten av advektivt porvattenflöde. Detta gjordes på åldrat sediment dels från en sötvattensbäck dels från en brackvattenstrand. Inget av de två sedimenttyperna visade någon skillnad i mineraliseringshastighet i jämförelse med diffusivt styrda system. Det är i motsats till tidigare marina studier, men är i linje med den första studien, där mineraliseringshastigheten var oberoende av redox-förhållande.</p><p>Den generella slutsatsen från den här studien är nödvändigheten att studera samma aspekter i olika typer av akvatiska system, eftersom responsen verkar vara annorlunda beroende på system, t.ex. söt- brack- och saltvatten. Faktorer som kan förklara de här skillnaderna finns ännu inte, vilket gör att småskaliga studier och modeller blir viktiga verktyg för att utreda detta.</p> / <p>Organic matter mineralisation is a key parameter that affects most other element transformations associated with organic matter. A substantial part of aquatic organic matter (OM) mineralisation takes place at the interface between sediment and water. Understanding OM mineralisation is important at both the micro and macro scales, since it drives many biogeochemical cycles. OM mineralisation rates are widely measured, but generally not all the natural factors possibly affecting the rates, such as physical forcing, are considered.</p><p>This thesis examines the mineralisation rates of indigenous OM in fresh and brackish surface sediments, subjected to different physical forces inducing changed redox conditions, resuspension, and advective pore water flow. Five experiments were performed to this end.</p><p>Aged surface sediment from a freshwater river was subjected to different redox conditions favouring oxic respiration, sulphate reduction, and methanogenesis, respectively. Results indicated no difference in mineralisation rate irrespective of treatment. This contradicts what has been found in marine environments, where anoxic mineralisation rates are lower than oxic ones.</p><p>Further, two studies of resuspension of brackish sediments were performed, one addressing the impact of the frequency and duration of the resuspension events, and the other addressing the impact of resuspension on different types of sediments. The studies found that very brief resuspension events followed by calm periods of up to 48 h increased mineralisation rates by five times compared to diffusion, and more than doubled the rate compared to continuous or long-term resuspension. The short-term events were possibly favoured because resuspension physically disturbs the arrangement of a stable bacteria community. Mineralisation rates on sediments dominated by very fine, fine, or medium-grained sand were the same, while coarse sand displayed a significantly lower rate. The similar rates of the three first sediment types could stem from access to labile OM, due to an ongoing algae bloom when the sediment and water samples were collected.</p><p>Finally, the effect of advective pore water flow on aged sediment from one fresh and one brackish sediment was studied. Neither of the sediments displayed a mineralisation rate different from those occurring in incubations in which only diffusive exchange occurred. This contradicts the findings of previous marine studies, but is in line with the first study, which did not detect different mineralisation rates irrespective of redox conditions.</p><p>The general conclusion is that it is necessary to study the same physical forces in different aquatic environments, since responses appear to differ, for example, between freshwater, brackish, and marine environments. Factors explaining these differences have not yet been expressed, making small-scale studies and modelling a challenge for future research.</p>

The increased use of biomass and recovered waste fuels in favor of fossil fuels for heat and power production is an important step towards a sustainable future. Combustion of waste fuels also offers several advantages over traditional landfilling, such as substantial volume reduction, detoxification of pathological wastes, and reduction of toxic leaches and greenhouse gas (methane) formation from landfills. However, combustion of recovered waste fuels emits more harmful trace elements than combustion of other fuels. These elements are distributed between bottom ash, fly ash and flue gas, depending on the elements partitioning and enrichment behavior. Volatilized harmful trace elements are mainly enriched in the submicron fly ash fraction. If emitted to the atmosphere, submicron particles can penetrate deep into the alveoli of the lungs, causing severe impacts on human health. Consequently, to reduce ash related problems and to control the emissions to the atmosphere, there is an increased need for understanding the physicochemical processes involved in ash transformation, including particle formation. The objective of this thesis was to carefully and systematically study the fate of trace elements during combustion, i.e. the chemical form of the elements and the partitioning behavior, by means of chemical equilibrium model calculations, X-ray diffraction, microscopy techniques and various spectroscopy methods. The influence of some fuel additives was also analyzed. Primarily, the elements copper, chromium and arsenic were studied. An initial review and evaluation of the content of thermodynamical data in commercial thermochemical databases used for chemical equilibrium model calculations showed that there was a significant difference in number of included phases and species between databases. Thermodynamical data also differed between databases, although in general less for condensed phases than for gaseous species. A state-of-the-art database for Cu, Cr and As was compiled and used for further chemical equilibrium model calculations. The fate of Cu, Cr and As was determined in combustion experiments on wood impregnated with copper, chromium and arsenic (CCA) in a bench scale reactor (15 kW). The results showed that global chemical equilibrium model calculations predicted the overall fate of Cu, Cr and As in bottom ash and ash particles quite well. However, compared to the experimental results the global model overpredicted the formation of refractory calcium arsenates, thus the arsenic volatilization was found to be higher then the predicted volatilization. In terms of chromium volatility, copper was found to be an important refractory element forming stable CuCrO2(s) and CuCr2O4(s) that suppressed the formation of CrO2(OH)2(g). The retention and speciation of Cu, Cr and As in bottom ash was further determined from combustion experiments of CCA wood fuel particles in a single particle reactor. Local chemical equilibrium model calculations were performed to simulate the combustion stages of a burning CCA treated wood fuel particle: drying, devolatilization, char burning and post-combustion. The results from the work showed that a mix of global and local chemical equilibrium model calculations is needed to describe the reality and that the combustion stages are partially overlapping. The fate of harmful trace elements, including Cu, Cr and As, was finally studied in full scale (65 MW) combustion experiments. Particles from the raw flue gas emissions were sampled and analyzed. The comparison with chemical equilibrium model calculations showed that the model explained the results well, but due to lack of thermodynamic data for K2ZnCl4(s), the formation of this phase could not be predicted.

According to previous research, students show difficulties in learning redox reactions. By the historical development different redox models exist to explain redox reactions, the oxygen model, the hydrogen model, the electron model and the oxidation number model. This thesis reports about three studies concerning conceptions held by secondary school students of redox reactions. A textbook analysis is also included in the thesis. The first study was an investigation of the students’ use of redox models in inorganic contexts, their use of the activity series of metals, and the students’ ability to transfer redox knowledge. Then the students’ work with an open-ended biochemical task, where the students had access of the textbook was studied. The students talk about redox reactions, the questions raised by the students, what resources used to answer the questions and what kind of talk developed were investigated. A textbook analysis based on chemistry books from Sweden and one book from England was performed. The redox models used as well as the dealing with redox related learning difficulties was studied. Finally, the students’ conceptions about redox in inorganic, organic and biochemistry after completed chemistry courses were studied. The results show that the students were able to use the electron model as a tool to explain inorganic redox reactions and the mutuality of oxidation and reduction was fundamental. The activity series of metals became a tool for the prediction of reducing agent in some reactions. Most of the students rejected that oxygen is a prerequisite for a redox reaction. In the biochemical task the resource most used to answer the raised questions were the students’ consultation of the textbook – together or individually. Most questions resulted in short answers and the majority of these questions were answered. Questions concerning redox were analysed by the students and integrated into a chemical context but they could neither identify the substances oxidised or reduced nor couple the concepts to transfer of hydrogen atoms. The majority of these redox questions became unanswered. The textbook helped the students to structure a poster as well as to answer basic chemistry questions. For questions about organic and biochemical redox, the book was of no help. The textbook analysis showed that all historical redox models are used. Different models are used in inorganic, organic and biochemistry. The mutuality of oxidation and reduction is treated differently in subject areas. The textbooks did not help the reader linking the different redox models that were used. Few redox-related learning difficulties are addressed in the books. After completed chemistry courses the students had major problems to justify a redox reaction explained by transfer of hydrogen atoms both in the organic and biochemistry examples.

The purpose of this diploma work was to investigate the problem of insufficient fibre recovery in the dissolved air flotation-cell at the new thermomechanical pulping-line at Braviken Paper Mill. An investigation of the effect of process parameters on the removal efficiency in the micro-flotation process was undertaken. The experiments were carried out for two setups at the Noss pilot plant with a small-scale flotation unit. Factorial design helped plan the experiments and four factors were controlled; temperature, fibre-size distribution, water quality and feed concentration. Three samples, feed, overflow and filtrate, were taken from each experiment and concentration measurements were made. The results were analyzed using the software MODDE. The results from showed an influence from the fibre-size distribution. To see if the fibre-size distribution really had an effect on the results, follow-up experiments were carried out. These experiments showed no influence from temperature, fibre-size distribution or water quality. This concludes that none of those three factors influenced the results significantly. Additional experiments were done to examine the influence from concentration and fibre-size distribution on the flotation efficiency and these showed an influence from the feed concentration. When increasing the feed concentration the efficiency of the flotation process decreased.

Metal-hydrocarbon complexes were prepared in a laser-vaporization molecular beam source and studied by single-photon zero electron kinetic energy (ZEKE) and mass-analyzed threshold ionization (MATI) spectroscopy. The ionization energies and vibrational frequencies of the metal complexes were measured from the ZEKE and MATI spectra. Metal-ligand bonding and low-lying electronic states of the neutral and ionized complexes were analyzed by combining the spectroscopic measurements with quantum chemical calculations and spectral simulations. In this dissertation, the metal complexes of mesitylene, aniline, cyclooctatetraene, benzene, ethene, and propene were studied. For each complex, different effects from metal coordination have been identified. Although metal-bis(mesitylene) sandwich complexes may adopt eclipsed and staggered conformations, the group VI metal-bis(mesitylene) complexes are determined to be in the eclipsed form. In this form, rotational conformers with the methyl group dihedral angles of 0 and 60° are identified for the Cr complex, whereas the 0° rotamer is observed for the Mo and W species. The unsuccessful observation of the 60° rotamer for the Mo and W complexes is the result of its complete conversion to the 0° rotamer in both He and He/Ar carriers. For group III metal aniline complexes, the ZEKE spectrum of each complex exhibits a strong origin band, a short M+-aniline stretching progression, and several low-frequency ligand based vibrational modes. The intensities of most of the transitions can be explained by the Franck-Condon (FC) principle within the harmonic approximation. However, the intensity of the low frequency out-of-plane ring deformation mode is greatly overestimated by the FC calculations and may be caused by the anharmonic nature of the mode. Although aniline offers two possible binding modes for the metal atoms, a п binding mode is identified with the metal atom over the phenyl ring. For Ce, Pr, and Nd(cyclooctatetraene) complexes multiple band systems are observed. This is assigned to the ionization of several low-lying electronic states of the neutral complex. This observation is different from the Gd(cyclooctatetraene) complex, for which a single band system is observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field. The ZEKE spectrum of the Gd(benzene) complex exhibits a strong origin band, whereas the spectrum of Lu(benzene) displays a weak one. The benzene ring is planar in the Gd complex, but bent in the Lu complex. Dehydrogenation and C-C coupling products are observed in the reaction of La atom and ethene/propene. For the La and ethene reaction, La(C2H2) and La(C4H6) complexes are identified. With propene, C-H bond activation leads to the formation of the La(C3H4) and H-La(C3H5) complexes, whereas the C-C coupling yields the La(trimethylenemethane) complex. In addition, the La(CHCCH3) and La(CHCHCH2) isomers of La(C3H4) are observed, which are produced by the 1,2- and 1,3-hydrogen elimination of propene.