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A new active LO phase shifter was introduced and implemented in a 2x2 wide band MIMO receiver. The chip was designed with STMicroelectronics 90nm technology. The main advantages of the proposed phase shifter over previous works included a wide band range, high resolution and small area. The phase shifter is based on the dependency of the inverter propagation delay on the load capacitance. Simply, by changing the load capacitance of an inverter, a different propagation delay is generated. A number of these controllable delay cells are cascaded to provide the required phase-shift. In order for the delay cells to reduce the required amount of phase-shifting the I&Q swap circuit is introduced. The I&Q swap circuitry reduces the phase-shifting by one fourth of the original range. The wide band phase shifter is suitable for multi-standard radios, since just one phase shifter is needed to support all standards. This capability of the phase shifter could potentially reduce the size of the die and simplify the design. The measurement shows that the phase shifter is able to provide 360˚ of phase-shifting at the output base band signal when the LO is varying from 1.5GHz to 6GHz. A wider range of the phase shifter is achievable by reducing the capacitance load and increasing the number of cascaded delay cells. The proposed phase shifter is capable of achieving a very high resolution. The resolution of the phase shifter is a function of the inverter current capability and the load capacitance. The measurements show the average resolution of the proposed phase shifter is about 1.32ps. Passive components usually take up a large area on the chip. A MOS capacitor is used as the load to reduce the area of the proposed phase shifter. A method is proposed to improve the phase shifter stability over the temperature and process variations. This method is based on the fact that the propagation delay of an inverter is inversely proportional to the power supply. Therefore, the phase shifters’ power supply must be varied to maintain a relatively constant phase shifter resolution over the temperature and process variations.

The objective of the current research project relies on implementation of solvent-free, green and environmentally friendly solid phase microextraction (SPME) sample preparation alternative in the area of complex sample characterization. The advantages that the technique offers in comparison to traditional methods of sample preparation including solvent-free implementation, short sample preparation times, small sample amount requirements, advanced automation capability and minimization of matrix effects are effectively employed during ex vivo and laboratory investigations of complex samples. More important, the underlying features of the technique including miniaturized format, nonexhaustive extraction recoveries and on-site compatibility were fully exploited in order to investigate the metabolome of biological systems directly on the site. Hence, in vivo SPME extraction format was employed in direct immersion SPME sampling of biological systems, hence eliminating the crucial prerequisites associated with multiple preparative steps and incorporation of metabolism quenching that are encountered during implementation of traditional sample preparation methods in global metabolite analysis. Furthermore, in vivo sampling format was hyphenated to comprehensive two-dimensional gas chromatography – time-of-flight mass spectrometry (GCxGC-ToFMS) for high-resolution sampling of volatile and semivolatile metabolites in ‘Honeycrisp’ apples. The initial stages of the project involved evaluation of performance characteristics of commercial SPME extraction coatings in terms of extraction selectivity, extraction sensitivity and desorption efficiency by employing headspace SPME analysis of both aqueous standards spiked with representative volatile and semivolatile metabolites as well as the apple homogenate. DVB/CAR/PDMS coating was selected on the basis of optimum metabolite coverage and extraction sensitivity and was consequently employed during ex vivo and in vivo sampling assays corresponding to determination of volatile and semivolatile metabolites. The former extraction methodology incorporated appropriate sample preparation steps for quenching metabolic activity so that the relevant metabolome profile is not biased against unstable metabolites and those that are susceptible to inter-metabolite conversions which adversely impact preservation of metabolite identity. The two sample preparation assays were compared in terms of metabolite coverage and analytical precision in order to identify SPME route toward characterization of more representative metabolome and determination of instantaneous and more ‘true’ metabolism snapshoot. This is the first report illustrating the implementation of in vivo direct immersion SPME assay for non invasive determination of endogenous fruit metabolites whose profiles and contents are highly correlated to a multitude of influential fruit quality traits.

ix, 303 leaves : ill., tables, photos ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physical and Inorganic Chemistry, 1976

Research Doctorate - Doctor of Philosophy (PhD) / Determining the operating parameters and design considerations for dense phase (non-suspension) conveying of fine powders in pneumatic systems typically use empirical, steady-state modelling techniques, as the mechanisms of the flow behaviour are still not fully understood. However, this necessary simplification in the modelling of the dense phase flow still presents significant challenges in ensuring that the predicted outcomes adequately reflect the physical nature of the flow, and therefore provide good design guidance. This thesis represents an examination and development of techniques required for designing dense phase systems of fine powders in three specific areas; prediction of a materials potential to dense phase convey, solids friction correlations and their subsequent effect on pressure drop prediction, and modelling the solids flow from a local perspective. The dense phase capability analysis was conducted by reviewing the current predictive techniques utilising known dense phase material data. It was apparent in the thesis that there were distinct strong predictive regions in all the diagrams; however some diagrams showed areas with weak predictive regions. This work also illustrated the difficulties in comparing different de-aeration rate techniques and significantly, a new mode of flow predictive chart was developed which eliminated the need to determine de-aeration rates while still maintaining distinctly strong dense phase predictive capability. Solids friction based pressure models invariably use a power law which require determination of co-efficient/s and exponent/s. Detailed in this thesis is the research which shows why solutions do not always occur in these power law based friction models and defines a method of determining stable and meaningful values for the exponents. Furthermore, a generic air/particle parameter based solids friction model was developed which is a clear advancement in defining the frictional resistance of dense phase pneumatic conveying of powder. This thesis also proposes a new continuum model which calculates the force balance between the conveying air flow, the resistance of the particles and geometrical effects, like bends. The solution to this model provides qualitative information on fine powder dense phase flow velocity from a solids flow perspective and represents a major step in advancing dense phase modelling from a particle flow basis.

Research Doctorate - Doctor of Philosophy (PhD) / Determining the operating parameters and design considerations for dense phase (non-suspension) conveying of fine powders in pneumatic systems typically use empirical, steady-state modelling techniques, as the mechanisms of the flow behaviour are still not fully understood. However, this necessary simplification in the modelling of the dense phase flow still presents significant challenges in ensuring that the predicted outcomes adequately reflect the physical nature of the flow, and therefore provide good design guidance. This thesis represents an examination and development of techniques required for designing dense phase systems of fine powders in three specific areas; prediction of a materials potential to dense phase convey, solids friction correlations and their subsequent effect on pressure drop prediction, and modelling the solids flow from a local perspective. The dense phase capability analysis was conducted by reviewing the current predictive techniques utilising known dense phase material data. It was apparent in the thesis that there were distinct strong predictive regions in all the diagrams; however some diagrams showed areas with weak predictive regions. This work also illustrated the difficulties in comparing different de-aeration rate techniques and significantly, a new mode of flow predictive chart was developed which eliminated the need to determine de-aeration rates while still maintaining distinctly strong dense phase predictive capability. Solids friction based pressure models invariably use a power law which require determination of co-efficient/s and exponent/s. Detailed in this thesis is the research which shows why solutions do not always occur in these power law based friction models and defines a method of determining stable and meaningful values for the exponents. Furthermore, a generic air/particle parameter based solids friction model was developed which is a clear advancement in defining the frictional resistance of dense phase pneumatic conveying of powder. This thesis also proposes a new continuum model which calculates the force balance between the conveying air flow, the resistance of the particles and geometrical effects, like bends. The solution to this model provides qualitative information on fine powder dense phase flow velocity from a solids flow perspective and represents a major step in advancing dense phase modelling from a particle flow basis.

Thesis (Ph. D - Hydrology and Water Resources) / Includes bibliographical references (leaves 208-221).

Thesis (Ph.D.)--Tufts University, 2005. / Adviser: Peggy Cebe. Submitted to the Dept. of Physics. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;