Operation of Energy MicroGrids

Integrated Operation is a strategy to operate the Energy MicroGrid as an integrated system. In this strategy, a CHP plant, an electric water heater, and thermal storage were operated to support both electricity and heat networks of the Energy MicroGrid. An Integrated Optimal Power Flow was formulated and was used to investigate the advantages of this Integrated Operation. Simulations indicated that Integrated Operation minimised generation curtailment and load shedding. It also reduced electricity imported from the main grid and the operating cost.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Single Molecule Solvation and Its Effects on Tautomeric Equilibria in a Self-Assembled Capsule

A self-assembled cylindrical capsule provides a nanoscale environment that affects keto−enol equilibria. The equilibrium constants for encapsulated β-ketoesters show values that differ by an order of magnitude from that of the free tautomers in solution. For complexes with a single, large encapsulated guest, the inner surfaces of the capsule and the seam of the hydrogen bonds influence the equilibrium between the encapsulated keto and enol forms. For complexes of smaller β-ketoesters, the coencapsulated solvent influences the equilibria. The solvent reduces the space available and affects the positioning of the ester in the capsul

Influence of coatings on ion release from large diameter metal-on-metal hip bearings

The reduction of wear debris and metal ions from metal-on-metal (MoM) cobalt chromium molybdenum (CoCrMo) hip replacements is needed to help reduce the incidence of adverse tissue responses that cause the high clinical failure rate of these previously popular devices. In addition, infection following primary and revision hip joint replacement surgery is a major complication and has a serious impact on a patient's quality of life whilst putting an economic strain on the health care system; silver (Ag) has been used successfully in medicine as an antibacterial. A range of surface engineered CoCrMo surfaces were investigated for wear and ion release using up to 4 million cycles (Mc) of hip simulator wear testing. Wear testing was performed using both standard acetabular orientation (35°) and more clinically adverse orientation (60°). Bearings were further challenged halfway through a wear test by subjecting the bearings to repeated head and cup luxation-reposition cycles (partial dislocation followed by reduction), and then the effects on subsequent wear and ion release investigated. Electron beam physical vapour deposition (EBPVD) was used to deposit chromium nitride (CrN) and Ag-doped CrN (CrN-Ag; 17, 41 and 51 wt.% Ag) coatings onto large diameter CoCrMo heads and cups. A number of CoCrMo hips were triode plasma nitrided (TPN) or treated using a duplex process of TPN followed by CrN coating. A total of 27 hip bearings were tested, which included current, clinically available MoM controls. All coatings acted as a barrier to Co dissolution using a static immersion model. CrN coating reduced wear rates by 58% - 100% compared to conventional MoM hips. Most notably there was a 99% reduction in Co release into the simulator lubricant when tested at both cups inclinations following 2.00 Mc, and a reduction of 89% when tested following a severe coating damage protocol. The MoM bearings showed signs of the selfpolishing phenomenon often associated with these types of bearings. Wear of the CrN-Ag bearings was similarly lower than the MoM controls in all wear phases, and the CrN-Ag coatings reduced Co release. Approximately 70% of the total Ag released over duration of the test was released over the first 0.17 Mc cycles of wear testing and was predominantly contained within wear particles rather than as ionic Ag. Adverse head and iii cup damage resulted in catastrophic failure of the 17 wt.% Ag coating, but the 51 wt.% Ag coating was the lowest wearing, indicating that the self-lubricating properties of Ag played a role in the tribological contact. The TPN bearings wore almost twice as much as the MoM controls and released twice the amount of Co; the duplex bearings wore almost 5-times more than the CrN coating and did not act as a barrier to Co release. The poor wear and ion release characteristics of the bearings that had been nitrided was attributed to nitrogen (N) having a stronger affinity for Cr than Co. Although the results of the present thesis indicate that both wear and ion release can be reduced by utilising EBPVD CrN-based surface coatings, it is likely that, given the current observations of high rates of failure of MoM implants, that surface engineering of MoM will not be embraced in the near future. However, there may be opportunities to exploit this technology in alternative orthopaedic implant applications.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Helical Folding of Alkanes in a Self-Assembled, Cylindrical Capsule

The reversible encapsulation of a series of normal alkane guests in a cylindrical host was studied by NMR methods. For small hydrocarbons such as n-pentane or n-hexane, two guests enter the host, and they move freely within. With n-heptane no encapsulation takes place. For longer alkanes such as n-decane, a single guest enters and the aromatic walls of the host are seen to twist to avoid empty spaces and increase favorable interactions with the hydrocarbon. The best guest (n-undecane) adopts a conformation with minimal gauche interactions. The longest alkane accommodated, n-tetradecane, adopts a helical conformation to fit in the cavity, a shape that maximizes CH/ð interactions with the aromatic walls of the receptor. These reciprocal conformational changes are discussed in terms of optimal host/guest interaction

Individual Solvent/Solute Interactions through Social Isomerism

Reversible coencapsulation of a solute molecule and a single solvent molecule takes place in solution at ambient temperature. Two isomeric complexes are formed (social isomers), and their relative energies are assessed by NMR methods. Intermolecular interactions between 3 aromatic solutes and 15 common solvents are evaluated

Isotopomer Encapsulation in a Cylindrical Molecular Capsule: A Probe for Understanding Noncovalent Isotope Effects on a Molecular Level

Isotope effects for the encapsulation of deuterated versus nondeuterated guests are determined. This system involves the use of social isomers, and the origin of the isotope effect is localized to methyl groups interacting with aromatic rings

Encapsulation Induces Helical Folding of Alkanes

Thumbnail image of graphical abstract Doing the twist: Incorporation of long hydrocarbons during the self-assembly of a cylindrical capsule containing an elongated cavity lined with eight benzene rings and additional π surfaces induces helical conformations of the chains so that they are fully encapsulated within the cavity (see picture)