The role of sustainable and natural waste management processes such as composting are increasingly becoming more important in tackling the current environmental challenge of the amount of waste that is being produced. However a potential risk of composting facilities is the release and dispersal of bioaerosols that might result in adverse health effects in sensitive receptors. Therefore, environmental regulators request regulatory risk assessments from composting facilities that are within 250m of sensitive receptors to assess the risk posed by bioaerosols. The prior art in compost related bioaerosol release and dispersal assessment is not extensive and gaps in the understanding of bioaerosols at source, on release from composting facilities and at receptor remain. Therefore, this research was undertaken to address some of these gaps in the current knowledge and to improve the understanding of the characterisation and dispersal of bioaerosols emitted from compost. Therefore firstly two studies were completed in regards to the characterisation of bioaerosols emitted from compost, in particular in improving the understanding of their aggregation and size distribution. In this context, a novel methodology (the compost tumbler) was developed to release and measure bioaerosols in experimental conditions. Data was generated using a combination of culturing and scanning electron microscopy methods to characterise the aggregation and size distribution of bioaerosols emitted from compost. Secondly, site work was conducted to validate the results of these controlled experiments and characterise the aggregation and size distribution of bioaerosols emitted from composting facilities. These controlled experiments and site work showed evidence of aggregation in bioaerosols released from compost. However, the majority of these bioaerosols were in single cell units hence they are more likely to be dispersed for longer distances. Following this, other studies were conducted in regards to the dispersal of bioaerosols emitted from compost, in particular in improving the understanding of bioaerosol concentration prediction by air dispersion modelling. Firstly preliminary air dispersion modelling was completed to assess the ability of a commercial air dispersion model,ADMS 3.3, to predict bioaerosol emissions from composting facilities compared to bioaerosol concentrations measured by on-site downwind bioaerosol sampling. Folowing this, the sensitivities of ADMS 3.3 were analysed and the effect of different modelling parameters on predicted bioaerosol concentrations were assessed. Finally, a final assessment of the potential of ADMS 3.3 to predict bioaerosol emissions from composting facilities was conducted. The overall results from the modelling studies indicated that ADMS 3.3 was not able to consistently predict absolute downwind bioaerosol concentrations at composting facilities. However it was also concluded that ADMS 3.3 can be a useful tool for the initial screening and assessing relative changes of bioaerosols at a compost facility, provided that the detailed assessment of absolute bioaerosol emissions are made in conjunction with measurement of downwind bioaerosol concentrations. The research presented in this thesis makes a significant contribution to knowledge in terms of improving the understanding of the characterisation and dispersal of bioaerosols emitted from composting facilities.

Equations of chemical kinetics typically include several distinct time scales. There exist many methods which allow to exclude fast variables and reduce equations to the slow manifold. In this thesis, we start by studying the background of the quasi equilibrium approximation, main approaches to this approximation, its consequences and other related topics. We present the general formalism of the quasi equilibrium (QE) approximation with the proof of the persistence of entropy production in the QE approximation. We demonstrate how to apply this formalism to chemical kinetics and describe the difference between QE and quasi steady state (QSS) approximations. In 1913 Michaelis and Menten used the QE assumption that all intermediate complexes are in fast equilibrium with free substrates and enzymes. Similar approach was developed by Stuekelberg (1952) for the Boltzmann kinetics. Following them, we combine the QE (fast equilibria) and the QSS (small amounts) approaches and study the general kinetics with fast intermediates present in small amounts. We prove the representation of the rate of an elementary reaction as a product of the Boltzmann factor (purely thermodynamic) and the kinetic factor, and find the basic relations between kinetic factors. In the practice of modeling, a kinetic model may initially not respect thermodynamic conditions. For these cases, we solved a problem: is it possible to deform (linearly) the entropy and provide agreement with the given kinetic model and deformed thermodynamics ? We demonstrate how to modify the QE approximation for stiffness removal in an example of the CO oxidation on Pt. QSSA was applied in order to get an approximation to the One dimensional Invariant Grid for oxidation of CO over Pt. The method of intrinsic low dimension manifold (ILDM) was implemented over the same example (CO oxidation on Pt) in order to automate the process of reduction and provide more accurate simplified mechanism (for one-dimension), yet at the cost of a significantly more complicated implementation.

Synthesis and characterisation of tetracyc1ic guanidinium phase transfer catalysts I and 11 from ethyl (R)-3-hydroxybutyrate was undertaken as well as the determnination of their pKa's to provide insight into the mechanism of their use in phase transfer catalysis. Their proficiency at catalysing the Michael addition of 2-hydroxy-l ,4-napth~guinone III to trans-~nitrostyrene IV was studied. Catalyst 11 showing improved reaction times and e.e.' s over I. The synthesis oftetracyc1ic guanidinium salt V was also attempted unsuccessfully, Synthesis of copper (1) hydride (CuH.X, X = H20 and pyridine) from three different routes (Wurtz Reaction [1], NaBH4 reduction [2] LiAIH4 reduction in pyridine [3]) and their subsequent investigation by inelastic neutron scattering (INS) techniques (neutron diffraction/spectroscopy) and X-Ray diffraction (XRD) provided insight into the structure of the copper hydride core and also the nature of the stabilising surface shell (H20 and pyridine respectively). Direct synthesis of Stryker's reagent [HCU{P(C6H5)3}]6 from copper (ll) acetate (Cu(OAc)2) and also its deuterium analogues [DCu{P(C6H5)3}]6 and [HCu{P(C6D5)3}]6 were achieved and the location of their hydride ligands using INS (SANDALS - neutron diffraction) was detennined. ; Synthesis of organometallic his-(n2 -π-allyl)M (M = Ni VI & Pd VII) cross-coupling catalysts from the Grignard reaction of metal halides and preparation of active Ni-terpyridyl complexes (general formula LNih, L = TPY) VIII - XI from the reaction of Ni(CODh and h with the starting material TPY's was achieved and vibrational INS spectra (TOSCA - neutron spectroscopy) was used to investigate the low energy vibrations which are linked to catalytic activity. Similar studies were performed on the commercially available Pd stabilised NHC PEPPSl pre-catalysts (IPr XII and IMes XIII)).

No description available.

This thesis presents an investigation into the interactions between IL surfaces and gases through studying the kinetics of absorption, adsorption and desorption. A model for absorption is presented in which a gaseous molecule that impacts the surface first enters a physisorbed state, from which it can either desorb or be absorbed into the bulk IL.

The similar chemical properties of sulfur, selenium and tellurium have been used to enable investigation of altering the size of occluded species, AOx (A = sulfur, selenium, tellurium and x = 0, 3 or 4), within sodalite based framework materials. Geomimetic synthesis of nosean Na8[AlSiO4]6AOx where A = sulfur, selenium, tellurium and x = 0, 3 or 4 has been investigated and a synthesis method for pure nosean selenate has been reported. Beryllosilicate and beryllogermanate sodalite compounds M8[BeSiO4]6A2 where M = Fe, Mn, Zn, Co, etc. and A = S, Se, Te have also been geomimetically synthesised and the magnetic effect of interchanging the original occluded sulfide for selenide resulted in a change in symmetry from P 3n to P222 at low temperature. Controlled mixed-metal beryllium compounds were targeted in order to investigate the effect of each M and combinations thereof. Unusual grinding effects have been observed for blue square planar Cu(Ph2SNH)2Cl2, whereby a reversible colour change to green occurs on grinding or application of a sheer force. Evidence points towards the possibility that a sheer effect, induced by way of grinding, causes a twisting of the ligands, inducing a reversible colour change, with properties tending towards those of the pseudo-tetrahedral allogon in the square planar polymorph. Anion metathesis has been found to occur within a system containing [Cu(Ph2SNH)4]Cl2, Ph2SNH.H2O and NaBF4. There is evidence indicating that, on grinding, an additional Ph2SNH ligand can be coordinated to the copper centre. This would be the first example of a purely solid state reaction in which the maximum coordination number for a ligand could be controlled by the counterion.

The results are reported of an investigation into the influence of preparative conditions on catalyst performance, using silica-supported nickel as a model system. Nickel(Il)dimethylglyoximate was precipitated from aqueous solution in the presence of silica in a stirred mixing vessel. After filtration, washing and drying, reduction with hydrogen produced a catalyst of metallic nickel supported on silica. Catalysts thus prepared were characterised according to nickel crystallite size, specific metal surface area, reducibility, and specific catalytic activity. Varying the precipitation conditions enabled the relationship between preparative parameters and catalytic performance to be examined. The crystal size distribution of the Nickel(Il)dimethylglyoximate catalyst precursor was dependent upon a variety of precipitation parameters, but the properties and performance of the final catalyst were found to be independent of the preparation conditions. The reduction of nickel(H)dimethylgloximate by heating in hydrogen is accompanied by a sublimation process. This vapour-phase redistribution of the material prior to reduction is believed to be responsible both for the exceptionally high surface areas (>200m 2 /gNi) observed for catalysts prepared by this route, and for the discovered lack of correlation between catalytic activity and preparation conditions.

Both pulsed and continuous sources of helium nanodroplets were employed for the investigation of molecular dopants. The doped helium droplets were investigated with the use of a range of techniques including electron impact ionization mass spectrometry, electronic spectroscopy and infrared (vibrational) spectroscopy. Electron impact mass spectrometry was used to investigate the influence of droplet size (<N> = 4000 - 80 000 helium atoms) and dopant species on the formation of helium cluster cations. The abundance of larger helium cluster cations, produced from pure helium droplets, was found to increase with droplet size until an asymptotic limit was reached for <N> = 50 000 helium atoms. The effect of a dopant species was shown to alter the He[subscript n][superscript +]/ He[subscript 2][superscript +] (n ≥ 3) signal ratio for smaller droplet sizes and was attributed to the potential energy gradient created by the cation-dopant interaction, and its potential to draw the positive charge towards the centre of the droplet. Core-shell particles, consisting of a water core and a co-dopant outer shell, were produced using a sequential pickup technique and were analysed with electron impact ionization. Of the co-dopants used O[subscript 2], N[subscript 2], C[subscript 6]D[subscript 6] and CO[subscript 2] were found to provide a softening effect on the ionization of the water clusters, whilst CO and NO increased the fragmentation of some water cluster sizes. Results from ab initio calculations of [X(H[subscript 2]O)[subscript 2]][superscript +] cluster ions, where X = CO, N[subscript 2], Ar and CO[subscript 2], support the experimental results. A new method for recording electronic spectra of species that reside in long-lived metastable states inside the helium droplets was demonstrated using the electronic excitation of toluene into its S[subscript 1] state as an example. In another spectroscopic study, infrared depletion spectroscopy was used to record vibrational spectra of water-methane clusters. From a comparison of predicted vibrational frequencies from ab initio calculations with the experimental spectra, possible structures for the CH[subscript 4](H[subscript 2]O)[subscript n], for n = 1-3, were identified.

No description available.

A highly convergent and efficient fragment coupling strategy was implemented to assemble a variety of readily available triazine, amine and diamine molecular building blocks, to prepare an array of novel, highly functionalised water-soluble azacalixarenes. These unique compounds adopt a 1,3-alternate conformation in their energetic ground state and possess a 'pocket' within the cavity, which has the potential to bind small guest species inside. The synthesis, structure and binding properties of these unprecedented compounds are described herein. H I H-N R The Synthesis ofAtropisomers; Controlling Axial Chirality A general method applicable for the asymmetric synthesis of biaryl compounds, containing a pyridine or isoquinoline group, as a key structural feature was investigated. The strategy implemented involved the use of an enantiomerically pure chiral sulfoxide auxiliary which, when introduced ortho to a kinetically constrained biaryl axis was found to impart a high level of stereochemical control, through complementary electronic and steric effects. The introduction of the sulfoxide auxiliary resulted in the formation of two diastereomers and permitted a dynamic thermodynamic resolution; this generated the thermodynamically more stable atropisomer in an overall yield greater than 50%. A suitable method to remove the sulfoxide stereocentre whilst ensuring the transfer of enantiopurity in the final products was then explored. Oxidation of the sulfoxide group removed the stereocentre and gave a sulfone as the product with complete retention of enantiopurity (99: 1 er). A sulfoxide-lithiumelectrophile exchange reaction using phenylithium enabled the asymmetric synthesis of QUINAP, implementing a dynamic thermodynamic resolution into the strategy gave an overall yield of 58%. Finally, a number of racemic ortho substituted aryl pyridines were prepared to assess the effect of substituent size on the barrier to rotation, the barriers were quantified using variable temperature NMR.