Phase transition in malonic acid: An infrared study

Malonic acid is shown to undergo an interesting phase transition at 360 K when the two non-equivalent cyclic hydrogen-bonded dimers present in the low-temperature phase become equivalent.

Strategies of synthesis of aromatic polyketides using cyclohexa-1,4-and-1,3-dienes in Alder Rickett reactions

Cyclohexa-1, 4-dienes with appropriate substituents, obtained by birch reduction of the substituted benzene, react directly with derivatives of propiolic ester or aldchyde to yield aromatic polyketides. The following compounds have been synthesized; mycophenolic acid, nidulol methyl other, the root growth hormone 3, 5-dihydroxy-2-formyl-4-mythyl-benzoic acid, antibiotic DB 2073, the macrocyclic lactones lasiodiplodin and dihydrozearalenone and the biphenyl derivatives alternario and altenusin. Polyketide anthraquinones can be made from naphthoquinone precursors.

Reactions to changes in work control: Implications for self-determined and non-self-determined individuals

We investigate the extent to which individuals’ global motivation (self-determined and non-self-determined types) influences adjustment (anxiety, positive reappraisal) and engagement (intrinsic motivation, task performance) in reaction to changes to the level of work control available during a work simulation. Participants (N = 156) completed 2 trials of an inbox activity under conditions of low or high work control—with the ordering of these levels varied to create an increase, decrease, or no change in work control. In support of the hypotheses, results revealed that for more self-determined individuals, high work control led to the increased use of positive reappraisal. Follow-up moderated mediation analyses revealed that the increases in positive reappraisal observed for self-determined individuals in the conditions in which work control was high by Trial 2 consequently increased their intrinsic motivation toward the task. For more non-self-determined individuals, high work control (as well as changes in work control) led to elevated anxiety. Follow-up moderated mediation analyses revealed that the increases in anxiety observed for non-self-determined individuals in the high-to-high work control condition consequently reduced their task performance. It is concluded that adjustment to a demanding work task depends on a fit between individuals’ global motivation and the work control available, which has consequences for engagement with demanding work.

Computational studies on new chemical species in the gas-phase and the solid-state.

There is intense activity in the area of theoretical chemistry of gold. It is now possible to predict new molecular species, and more recently, solids by combining relativistic methodology with isoelectronic thinking. In this thesis we predict a series of solid sheet-type crystals for Group-11 cyanides, MCN (M=Cu, Ag, Au), and Group-2 and 12 carbides MC2 (M=Be-Ba, Zn-Hg). The idea of sheets is then extended to nanostrips which can be bent to nanorings. The bending energies and deformation frequencies can be systematized by treating these molecules as an elastic bodies. In these species Au atoms act as an 'intermolecular glue'. Further suggested molecular species are the new uncongested aurocarbons, and the neutral Au_nHg_m clusters. Many of the suggested species are expected to be stabilized by aurophilic interactions. We also estimate the MP2 basis-set limit of the aurophilicity for the model compounds [ClAuPH_3]_2 and [P(AuPH_3)_4]^+. Beside investigating the size of the basis-set applied, our research confirms that the 19-VE TZVP+2f level, used a decade ago, already produced 74 % of the present aurophilic attraction energy for the [ClAuPH_3]_2 dimer. Likewise we verify the preferred C4v structure for the [P(AuPH_3)_4]^+ cation at the MP2 level. We also perform the first calculation on model aurophilic systems using the SCS-MP2 method and compare the results to high-accuracy CCSD(T) ones. The recently obtained high-resolution microwave spectra on MCN molecules (M=Cu, Ag, Au) provide an excellent testing ground for quantum chemistry. MP2 or CCSD(T) calculations, correlating all 19 valence electrons of Au and including BSSE and SO corrections, are able to give bond lengths to 0.6 pm, or better. Our calculated vibrational frequencies are expected to be better than the currently available experimental estimates. Qualitative evidence for multiple Au-C bonding in triatomic AuCN is also found.

Association between feline immunodeficiency virus (FIV) plasma viral RNA load, concentration of acute phase proteins and disease severity

Veterinarians have few tools to predict the rate of disease progression in FIV-infected cats. In contrast, in HIV infection, plasma viral RNA load and acute phase protein concentrations are commonly used as predictors of disease progression. This study evaluated these predictors in cats naturally infected with FIV. In older cats (>5 years), log10 FIV RNA load was higher in the terminal stages of disease compared to the asymptomatic stage. There was a significant association between log10 FIV RNA load and both log10 serum amyloid A concentration and age in unwell FIV-infected cats. This study suggests that viral RNA load and serum amyloid A warrant further investigation as predictors of disease status and prognosis in FIV-infected cats.

Atomic Layer Deposition for optical applications: metal fluoride thin films and novel devices

Thin films of various metal fluorides are suited for optical coatings from infrared (IR) to ultraviolet (UV) range due to their excellent light transmission. In this work, novel metal fluoride processes have been developed for atomic layer deposition (ALD), which is a gas phase thin film deposition method based on alternate saturative surface reactions. Surface controlled self-limiting film growth results in conformal and uniform films. Other strengths of ALD are precise film thickness control, repeatability and dense and pinhole free films. All these make the ALD technique an ideal choice also for depositing metal fluoride thin films. Metal fluoride ALD processes have been largely missing, which is mostly due to a lack of a good fluorine precursor. In this thesis, TiF4 precursor was used for the first time as the fluorine source in ALD for depositing CaF2, MgF2, LaF3 and YF3 thin films. TaF5 was studied as an alternative novel fluorine precursor only for MgF2 thin films. Metal-thd (thd = 2,2,6,6-tetramethyl-3,5-heptanedionato) compounds were applied as the metal precursors. The films were grown at 175 450 °C and they were characterized by various methods. The metal fluoride films grown at higher temperatures had generally lower impurity contents with higher UV light transmittances, but increased roughness caused more scattering losses. The highest transmittances and low refractive indices below 1.4 (at 580 nm) were obtained with MgF2 samples. MgF2 grown from TaF5 precursor showed even better UV light transmittance than MgF2 grown from TiF4. Thus, TaF5 can be considered as a high quality fluorine precursor for depositing metal fluoride thin films. Finally, MgF2 films were applied in fabrication of high reflecting mirrors together with Ta2O5 films for visible region and with LaF3 films for UV region. Another part of the thesis consists of applying already existing ALD processes for novel optical devices. In addition to the high reflecting mirrors, a thin ALD Al2O3 film on top of a silver coating was proven to protect the silver mirror coating from tarnishing. Iridium grid filter prototype for rejecting IR light and Ir-coated micro channel plates for focusing x-rays were successfully fabricated. Finally, Ir-coated Fresnel zone plates were shown to provide the best spatial resolution up to date in scanning x-ray microscopy.

The kinetics and reactivity of several polyatomic free radicals in reactions with NO2, O2, Cl2, and HCl

In this thesis, the kinetics of several alkyl, halogenated alkyl, and alkenyl free radical reactions with NO2, O2, Cl2, and HCl reactants were studied over a wide temperature range in time resolved conditions. Laser photolysis photoionisation mass spectrometer coupled to a flow reactor was the experimental method employed and this thesis present the first measurements performed with the experimental system constructed. During this thesis a great amount of work was devoted to the designing, building, testing, and improving the experimental apparatus. Carbon-centred free radicals were generated by the pulsed 193 or 248 nm photolysis of suitable precursors along the tubular reactor. The kinetics was studied under pseudo-first-order conditions using either He or N2 buffer gas. The temperature and pressure ranges employed were between 190 and 500 K, and 0.5 45 torr, respectively. The possible role of heterogeneous wall reactions was investigated employing reactor tubes with different sizes, i.e. to significantly vary the surface to volume ratio. In this thesis, significant new contributions to the kinetics of carbon-centred free radical reactions with nitrogen dioxide were obtained. Altogether eight substituted alkyl (CH2Cl, CHCl2, CCl3, CH2I, CH2Br, CHBr2, CHBrCl, and CHBrCH3) and two alkenyl (C2H3, C3H3) free radical reactions with NO2 were investigated as a function of temperature. The bimolecular rate coefficients of all these reactions were observed to possess negative temperature dependencies, while pressure dependencies were not noticed for any of these reactions. Halogen substitution was observed to moderately reduce the reactivity of substituted alkyl radicals in the reaction with NO2, while the resonance stabilisation of the alkenyl radical lowers its reactivity with respect to NO2 only slightly. Two reactions relevant to atmospheric chemistry, CH2Br + O2 and CH2I + O2, were also investigated. It was noticed that while CH2Br + O2 reaction shows pronounced pressure dependence, characteristic of peroxy radical formation, no such dependence was observed for the CH2I + O2 reaction. Observed primary products of the CH2I + O2 reaction were the I-atom and the IO radical. Kinetics of CH3 + HCl, CD3 + HCl, CH3 + DCl, and CD3 + DCl reactions were also studied. While all these reactions possess positive activation energies, in contrast to the other systems investigated in this thesis, the CH3 + HCl and CD3 + HCl reactions show a non-linear temperature dependency on the Arrhenius plot. The reactivity of substituted methyl radicals toward NO2 was observed to increase with decreasing electron affinity of the radical. The same trend was observed for the reactions of substituted methyl radicals with Cl2. It is proposed that interactions of frontier orbitals are responsible to these observations and Frontier Orbital Theory could be used to explain the observed reactivity trends of these highly exothermic reactions having reactant-like transition states.

Kinetics of vapour phase oxidation of furfural on vanadium catalyst

Vapour phase oxidation of furfural over vanadium pentoxide catalyst was studied using an isothermal flow reactor in the temperature range of 220–280°C. Maleic anhydride and carbon dioxide are found to be formed from furfural by a parallel reaction scheme. The following rate equation based on the two-stage redox mechanism—the substance to be oxidized reduces the catalyst which in turn is reoxidized by oxygen from the feed—is found to explain the data satisfactorily.The reoxidation of the reduced catalyst was found to be the rate controlling step.

Gas-Solid Reactions: Photochemical Oxidation of Thioketones in the Crystalline State

Photochemical oxidation of 11 diaryl thioketones (1-11) was conducted in the solid state. Quite interestingly, of these only six were oxidized to the corresponding carbonyl compound whereas the rest were photostable. However, in solution all were readily oxidized. The difference in behavior between the thioketones in the solid state has been rationalized on the basis of molecular arrangement in the crystal. X-ray crystal structure analyses of four thioketones were carried out in this connection.

Magmatic evolution of topaz-bearing granite stocks within the Wiborg rapakivi granite batholith

This study brings new insights into the magmatic evolution of natural F-enriched peraluminous granitic systems. The Artjärvi, Sääskjärvi and Kymi granite stocks within the 1.64 Ga Wiborg rapakivi granite batholith have been investigated by petrographic, geochemical, experimental and melt inclusion methods. These stocks represent late-stage leucocratic and weakly peraluminous intrusive phases typical of rapakivi granites worldwide. The Artjärvi and Sääskjärvi stocks are multiphase intrusions in which the most evolved phase is topaz granite. The Kymi stock contains topaz throughout and has a well-developed zoned structure, from the rim to the center: stockscheider pegmatite equigranular topaz granite porphyritic topaz granite. Geochemically the topaz granites are enriched in F, Li, Be, Ga, Rb, Sn and Nb and depleted in Mg, Fe, Ti, Ba, Sr, Zr and Eu. The anomalous geochemistry and mineralogy of the topaz granites are essentially magmatic in origin; postmagmatic reactions have only slightly modified the compositions. The Kymi equigranular topaz granite shows the most evolved character, and the topaz granites at Artjärvi and Sääskjärvi resemble the less evolved porphyritic topaz granite of the Kymi stock. Stockscheiders are found at the roof contacts of the Artjärvi and Kymi stocks. The stockscheider at Artjärvi is composed of biotite-rich schlieren and pegmatite layers parallel to the contact. The schlieren layering is considered to have formed by velocity-gradient sorting mechanism parallel to the flow, which led to the accumulation of mafic minerals along the upper contact of the topaz granite. Cooling and contraction of the topaz granite formed fractures parallel to the roof contact and residual pegmatite magmas were injected along the fractures and formed the pegmatite layers. The zoned structure of the Kymi stock is the result of intrusion of highly evolved residual melt from deeper parts of the magma chamber along the fractured contact between the porphyritic granite crystal mush and country rock. The equigranular topaz granite and marginal pegmatite (stockscheider) crystallized from this evolved melt. Phase relations of the Kymi equigranular topaz granite have been investigated utilizing crystallization experiments at 100 to 500 MPa as a function of water activity and F content. Fluorite and topaz can crystallize as liquidus phases in F-rich peraluminous systems, but the F content of the melt should exceed 2.5 - 3.0 wt % to facilitate crystallization of topaz. In peraluminous F-bearing melts containing more than 1 wt % F, topaz and muscovite are expected to be the first F-bearing phases to crystallize at high pressure, whereas fluorite and topaz should crystallize first at low pressure. Overall, the saturation of fluorite and topaz follows the reaction: CaAl2Si2O8 (plagioclase) + 2[AlF3]melt = CaF2 (fluorite) + 2Al2SiO4F2 (topaz). The obtained partition coefficient for F between biotite and glass D(F)Bt/glass is 1.89 to 0.80 (average 1.29) and can be used as an empirical fluormeter to determine the F content of coexisting melts. In order to study the magmatic evolution of the Kymi stock, crystallized melt inclusions in quartz and topaz grains in the porphyritic and the equigranular topaz granites and the marginal pegmatite were rehomogenized and analyzed. The homogenization conditions for the melt inclusions from the granites were 700 °C, 300 MPa, and 24 h, and for melt inclusions from the pegmatite, 700 °C, 100 MPa, and 24/96 h. The majority of the melt inclusions is chemically similar to the bulk rocks (excluding H2O content), but a few melt inclusions in the equigranular granite show clearly higher F and low K2O contents (on average 11.6 wt % F, 0.65 wt % K2O). The melt inclusion compositions indicate coexistence of two melt fractions, a prevailing peraluminous and a very volatile-rich, possibly peralkaline. Combined petrological, experimental and melt inclusion studies of the Kymi equigranular topaz granite indicate that plagioclase was the liquidus phase at nearly water-saturated (fluid-saturated) conditions and that the F content of the melt was at least 2 wt %. The early crystallization of biotite and the presence of muscovite in crystallization experiments at 200 MPa contrasts with the late-stage crystallization of biotite and the absence of muscovite in the equigranular granite, indicating that crystallization pressure may have been lower than 200 MPa for the granite.

Construction of Stability Multipliers with Prescribed Phase Characteristics: an Improved Value for $\sigma

For a feedback system consisting of a transfer function $G(s)$ in the forward path and a time-varying gain $n(t)(0 \leqq n(t) \leqq k)$ in the feedback loop, a stability multiplier $Z(s)$ has been constructed (and used to prove stability) by Freedman [2] such that $Z(s)(G(s) + {1 / K})$ and $Z(s - \sigma )(0 < \sigma < \sigma _ * )$ are strictly positive real, where $\sigma _ * $ can be computed from a knowledge of the phase-angle characteristic of $G(i\omega ) + {1 / k}$ and the time-varying gain $n(t)$ is restricted by $\sigma _ * $ by means of an integral inequality. In this note it is shown that an improved value for $\sigma _ * $ is possible by making some modifications in his derivation. ©1973 Society for Industrial and Applied Mathematics.

Kinetics of vapour phase oxidation of furfural on vanadium catalyst

Vapour phase oxidation of furfural over vanadium pentoxide catalyst was studied using an isothermal flow reactor in the temperature range of 220–280°C. Maleic anhydride and carbon dioxide are found to be formed from furfural by a parallel reaction scheme. The following rate equation based on the two-stage redox mechanism—the substance to be oxidized reduces the catalyst which in turn is reoxidized by oxygen from the feed—is found to explain the data satisfactorily. The reoxidation of the reduced catalyst was found to be the rate controlling step.

Editorial of "International Journal of Critical Indigenous Studies, Volume 8, Number 2, 2015"

The articles in this edition address two critical concerns that can be broadly characterised as Indigeneity as a spectacle and the elision of Indigenous sovereignty by multiculturalism and diversity. The first article, by Maryrose Casey, examines nineteenth and early twentieth century Indigenous performances that drew on cultural practices for entertainment. She highlights how these commercially driven performances were, in fact, demonstrations of sovereignty that white colonisers paid to observe. A measure of the success of these demonstrations can be found in the reactions of audiences, which often involved disrupting the spectacle by physically occupying the performance space.

Possibility of a condensed phase of excitons because of phonon induced exciton-exciton pairing

In this paper we study the phonon-induced exciton-exciton interaction. It is found that the interaction can be attractive under certain conditions. Taking into account this attractive interaction, the pairing of excitons with opposite momenta is studied and the excitation spectrum determined. The results are similar to a system of bosons. There appears to be some possibility of superfluid behaviour.

Two-dimensional heat conduction with phase change in a semi-infinite mould

Analytical solution of a 2-dimensional problem of solidification of a superheated liquid in a semi-infinite mould has been studied in this paper. On the boundary, the prescribed temperature is such that the solidification starts simultaneously at all points of the boundary. Results are also given for the 2-dimensional ablation problem. The solution of the heat conduction equation has been obtained in terms of multiple Laplace integrals involving suitable unknown fictitious initial temperatures. These fictitious initial temperatures have interesting physical interpretations. By choosing suitable series expansions for fictitious initial temperatures and moving interface boundary, the unknown quantities can be determined. Solidification thickness has been calculated for short time and effect of parameters on the solidification thickness has been shown with the help of graphs.