2,477 research outputs found
Effects of relative phase and interactions on atom-laser outcoupling from a double-well Bose-Einstein condensate: Markovian and non-Markovian dynamics
We investigate aspects of the dynamics of a continuous atom-laser scheme
based on the merging of independently formed atomic condensates. Our
theoretical analysis covers the Markovian as well as the non-Markovian
operational regimes, and is based on a semiclassical (mean-field) two-mode
model. The role of the relative phase between the two condensates and the
effect of interatomic interactions on the evolution of the trapped populations
and the distribution of outcoupled atoms are discussed.Comment: to appear in J. Phys.
Development of the SAFT-γ Mie equation of state for predicting the thermodynamic behaviour of strong and weak electrolyte solutions
The thermodynamic modelling of fluid mixtures containing electrolytes using the SAFT-γ
Mie equation of state is addressed in detail in this thesis. The SAFT-γ Mie approach
allows the implementation of heteronuclear molecules using a group-contribution formalism,
and offers a versatile framework for developing models to describe molecules of varying
chemical functionality for a broad range of physical properties. In the present work, the
SAFT-γ Mie equation of state is extended to electrolyte mixtures with the incorporation
of the primitive unrestricted mean spherical approximation (MSA-PM) for describing the
Coulombic ion–ion interactions, and the Born solvation free energy to implicitly treat ion–
solvent polar interactions. Novel reformulations of the MSA-PM and Born theories within a
group-contribution framework are proposed in order to enable ionic species of any size and
chemical structure to be modelled, from small inorganic ions to large non-spherical charged
molecules. Taking carboxylate anions in linear alkyl chain molecules as an illustrative case
study, the proposed theory is shown to effectively account for localised charge effects arising
from the structural topology of the charged species. A holistic description of electrolyte
solutions is employed in this work; in addition to the short-range dispersion forces and
the long-range Coulombic interactions which are pertinent to such mixtures, the models
developed here also account for the formation of hydrogen bonds, ion-pairing phenomena,
and electrolyte dissociation equilibria. The proposed SAFT-γ Mie equation of state is used to
model aqueous solutions of strong electrolytes including alkali halide salts, hydrogen halide
acids, and alkali hydroxide bases. Aqueous solutions of sulphuric acid and nitric acid are
studied in detail by modelling these as speciating weak electrolytes. Finally, the treatment of
ion-pairing phenomena is investigated through a consideration of aqueous alkali nitrate salt
solutions. This work presents a new theoretical formulation and SAFT-γ Mie group models
for twenty species in total.Open Acces
Phenolate Derivatives of Octanuclear Iron-Oxo-Pyrazolato Complexes; Enantiomeric Resolution of T-Symmetry Species
Octanuclear ferric complexes involving achiral phenolates of the general formula [Fe8(μ-O)4(μ-pz)12(R-C6H4O)4], (R = 4-NO2, 4-CN, 4-F, 4-Cl, 4-I, 4-CH3O, and 3-NO3), where synthesized and characterized by single crystal X-ray crystallography, elemental analysis, 1H-NMR, UV-Vis, IR, 57Fe Mössbauer spectroscopy and electrochemical methods (cyclic and differential pulse voltammetry). Results indicate that the nature of the phenolate substituents allows the fine tuning of the spectroscopic data of the compounds.
Subsequently, this project focused on the resolution of the racemic octanuclear iron-oxo-pyrazolato complex [FeIII8(μ-O)4(μ-4-R-pz)12Cl4], [Fe8], (R=H, Me, Cl) to its P and M enantiomers. The strategy employed towards that goal was the diastereomer formation via substitution of the terminal chloride ligands with the chiral (R, S) 4-sec-butylphenol. Substitution with rac-4-sec-butylphenol reveals selectivity of the Fe8 P and M enantiomers for the phenolate R and S enantiomers, respectively. In the case of the 4-H-pz and 4-CH3-pz derivatives, this selectivity is manifested in their X-ray structures and 1H-NMR spectra. However it does not result in resolution, as the enantiomers cocrystallize as racemates. In contrast, the 4-Cl-pz derivative crystallized in non-centrosymmetric (chiral) space group, as determined by single crystal X-ray structure determination. The enantiomeric relationship of the P/R and M/S species was further established by Circular Dichroism experiments. These enantiomers are stable towards racemization. Re-introduction of the terminal chloride ligands was achieved via reaction of the P/R and M/S with HCl and the Circular Dichroism spectra of the products showed the presence of the P and M enantiomers in solution with their absolute configuration persisting.
The selective coordination of the R and S phenolates to the P and M complexes constitutes an unprecedented example of enantiomeric recognition in a non-biological system resulting in spontaneous resolution upon crystallization by employing only racemic reagents and media
WOMEN CONDUCTORS: A QUALITATIVE STUDY OF GENDER, FAMILY, ‘THE BODY’ AND DISCRIMINATION
The purpose of this study is to develop a broader appreciation of women’s experiences of conducting, focusing on issues concerning embodiment, body language, clothing and so forth in order to place emphasis on their life experiences. The research is based upon thematic analysis (TA) of qualitative interviews conducted with women conductors living in the UK (N=8) alongside detailed Media Content Analysis (MCA) of data derived from online magazines, online newspapers, online blogs and Internet articles. The results reveal prevalent gender discrimination, bias, sexism and misogyny against women in the conducting profession. Specifically, six broad themes emerged through the data analysis. These are: 1) gender discrimination (TA and MCA suggest that gender bias, discrimination, sexist and misogynist comments and attitudes still occur within the conducting profession); 2) factors that influence women conductors’ career development (TA suggests that families as well as a musical background of women conductors have motivated them to pursue and develop a musical career); 3) achieving balance (TA and MCA support that a balance between professional and personal life can be difficult to achieve); 4) clothing (TA and MCA suggest that clothing choices are very important for women conductors, affecting them personally in terms of how they are perceived by other musicians and/or audiences); 5) the conducting body (TA and MCA conclude that gender is not a factor affecting women’s bodily communication; however, their gestures may be perceived differently by people); and 6) conducting and leadership (TA and MCA suggest that the concept of the male ‘tradition’ is the main factor that has prevented women conductors from being seen as great leaders, therefore, women lack the experience and practice to develop their leadership abilities). Taken together, these factors highlight the continuing struggle that women experience in conducting today and provide an insight of how they cope with their profession
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