Deuteron Zeeman Relaxation of CD4 in the Isotropic Liquid, the Liquid Crystalline, and the Solid State of Several Substances

Measurement of deuteron Zeeman relaxation rates of CD4 dissolved in benzene, hexane, and the liquid crystals MBBA, EBBA, and Merck ZLI‐1132 and in pure CD4 gas as a function of temperature at 30.7 and 61.4 MHz shows that the CD4 is uniformly dispersed in the liquid solvents but resides in gas pockets when the solvents are in the solid state. Effects of centrifugal distortion were observed in the gas phase. The relaxation rate was found to be nearly independent of solvent, temperature, and pressure for the methane–liquid mixtures. This result is explained in terms of the extended diffusion model for the combined effects of free molecular rotation and collisions on the spectral density of quadrupolar interactions when the collisional and mean free rotational periods are of the same order of magnitude. It can also be interpreted in terms of the Fokker–Planck–Langevin model for rotational Brownian motion

Social inclusion and professional female migrants in multicultural Australia

The goal of the thesis is to scrutinise the experiences of professional female migrants in Australia. The study was undertaken in the context of the emergence of a policy focus on ‘social inclusion’ and ‘social exclusion’ in Australia and elsewhere and in the context of renewed debates in Australia about multiculturalism. Social inclusion refers to a policy focus on enabling the full participation of citizens in the life of the nation, including economic, social, cultural and political participation (Gillard & Wong, 2007). In turn, social exclusion refers to a policy focus on identifying and addressing groups whose participation is constrained, often measured along the dimensions of consumption, production, political engagement, social support and cultural life (see for example, Burchardt, Le Grand, & Piachaud, 2002; Richardson & Le Grand, 2002). This research is interested in testing the relevance of these frameworks for understanding and addressing the experiences of professional female migrants in multicultural Australia. The thesis involved a study of twenty professional female migrants living in Sydney who participated in in-depth interviews. All respondents belonged to a highly skilled occupational group and a prerequisite was that they held a primary professional qualification before migration to Australia. Participants, who were from both English speaking and non-English speaking backgrounds provided detailed narratives of their lives and experiences since migration to Australia, and these narratives provided a window into the specificities of professional female migrants’ perceptions of moving to Australia, settling in Australia and ‘belonging’ in Australia. These insights add to the body of knowledge on migration and social inclusion and exclusion. The research found that the relevance of the dominant social inclusion framework for analysing their migration and settlement experiences is only partial: this is because of the prioritisation of economic participation as a route to social inclusion. The social inclusion framework, consequently, fails to recognise the cultural dimension of social inclusion by assuming that social inclusion in multicultural Australia can be achieved and maintained through the active economic participation of Australian citizens. In addition, the study found that the dominant social inclusion policy framework does not recognise an important aspect of professional female migrants’ identity: transnational relationships and transnational belonging. In terms of the specificities of professional female migrants’ experiences, the thesis proposes a structure for talking about differences in experiences of inclusion that uses measures such as participation in paid work, either in mainstream or in ethno-specific workplaces; participation in social life, either in or in and beyond their own ethnic community; self-perception of being, or not being, included - a dimension that was often based on whether or not they experienced racism. Based on these factors, women’s experiences could be categorised as varying between deep, borderline, marginal and shallow inclusion. The thesis also finds that although social inclusion does not equal assimilation or a transition from being a migrant, social inclusion is possible in the context of ethnic and cultural differences

Efficient analysis of highly complex nuclear magnetic resonance spectra of flexible solutes in ordered liquids by using molecular dynamics

The NMR spectra of n-pentane as solute in the liquid crystal 5CB are measured at several temperatures in the nematic phase. Atomistic molecular dynamics simulations of this system are carried out to predict the dipolar couplings of the orientationally ordered pentane, and the spectra predicted from these simulations are compared with the NMR experimental ones. The simulation predictions provide an excellent starting point for analysis of the experimental NMR spectra using the covariance matrix adaptation evolutionary strategy. This shows both the power of atomistic simulations for aiding spectral analysis and the success of atomistic molecular dynamics in modeling these anisotropic systems. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4705271

Studies in stereochemistry by nuclear magnetic resonance

Nuclear Magnetic Resonance Spectroscopy is used to help solve two independent problems:- (i) The kinetic isomerization of β-aminocrotononitrile in both solid and solution phases is studied by using the relative intensity of the cis and trans methyl peaks from the n.m.r. At temperatures below 46°C, a solid state equilibrium of >95% cis isomer is formed, and above 46°C a 1:1 mixture of the two isomers forms as the compound slowly fuses. In solution, the trans isomer appears more stable at any temperature. The studies indicate β-aminocrotononitrile exists as either a pure cis monomer, or as a dimer or polymer of the cis and trans isomers. Dilution studies, acid catalysed kinetics, deuterium isotope effect studies, etc., support this observation. The structure of this dimer is proposed, and a reaction scheme supporting the experimental results suggested. (ii) Several ethyl ethers with an asymmetric centre next to the oxygen atom are studied by n.m.r. In each case, the methylene protons of the ethyl groups are non-equivalent, the chemical shift between them being about 20 cycles (at 60mc). This non-equivalence is attributed not only to the asymmetry of the carbon atom, but also to the induced asymmetry of the lone-pair electrons on the ether oxygen

NMR of orientationally ordered short-chain hydrocarbons

The proton NMR spectra of the straight-chain hydrocarbons from methane to n-hexane orientationally ordered in nematic liquid-crystal solvents are reviewed. The theory behind reorientation-vibration coupling (that explains the anisotropic splittings observed in the spectrum of methane) is discussed. This coupling is also important for ethane where the torsional motion about the C–C bond becomes an issue. The ratios of propane to ethane dipolar couplings are found to be independent of liquid crystal and of temperature: this demonstrates that the hydrocarbons are ‘magic solutes’, i.e. their orientational order results from a single anisotropic interaction that involves short-range size-and-shape effects. The longer chains n-butane, n-pentane and n-hexane (which give extremely complicated NMR spectra) exist in several symmetry-unrelated conformers. The spectra are analysed with the aid of evolution strategies. The dipolar couplings obtained are used in a model-free analysis (that is based on the constant ratio between ethane and propane dipolar couplings) to explore important information about the intermolecular potential. For example, the orientational order of longer conformers is favoured by the nematic phase