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Stratification, costratification, relative tensor-triangular geometry and singularity categories
Get PDFWe develop the theory of stratification for a rigidly-compactly generated tensor-triangulated category using the smashing spectrum and the small smashing support. Our first result, outside the stratified context, is that the Hochster dual of the Balmer spectrum is the Kolmogorov quotient of the smashing spectrum equipped with a certain topology. Within the stratified context, we prove that it suffices to check stratification on certain smashing localizations and we investigate connections between big prime ideals, objectwise-prime ideals and homological primes. We give a characterization of the Telescope Conjecture in terms of the homological spectrum and the homological support. Moreover, we study induced maps between smashing spectra and prove a descent theorem for stratification.
We develop the theory of costratification in the setting of relative tensor-triangular geometry and prove that costratification is equivalent to the colocal-to-global principle and cominimality. We also introduce and study prime localizing submodules and prime colocalizing hom-submodules, in the first case, generalizing objectwise-prime localizing tensor-ideals. Further, we prove that it suffices to check costratification on certain localizations with respect to smashing submodules and certain covers of the associated space of supports/cosupports. We apply our results to show that the derived category of quasi-coherent sheaves over a noetherian separated scheme is costratified, generalizing a result of Neeman for noetherian rings.
Finally, we classify the colocalizing subcategories of the singularity category of a locally hypersurface ring and then we generalize this result to schemes with hypersurface singularities
Transidentifications: Autofiction and translingualism in contemporary Francophone and Germanophone writing
No full textAbstract not currently available
A comparative study of proton exchange membranes: performance, stability and hydrogen crossover
Get PDFProton exchange membrane water electrolysis (PEMWE) presents itself as an attractive tool to support the renewable energy transition. By coupling these technologies together, a clean and environmentally friendly route to hydrogen production is created. Hydrogen can then act as an energy vector, delivering power areas where it is needed most. At the heart of the technology lies the proton exchange membrane (PEM) – a polymer that acts as a solid electrolyte, thus allowing protons to permeate through the device. The benchmark membrane is the Nafion™ brand, which has backbone similar to polytetrafluoroethylene (PTFE) and a long fluorinated carbon side chain capped with sulfonic groups. Aquivion® is another brand of membrane – similar to Nafion™, only that the side chain is shorter in length. Despite these membranes competing in identical markets, there are few existing comparative studies regarding their use in water electrolysis. The data that is available suggests the short side chain of Aquivion® yields optimal properties. Unfortunately, in recent months both of these membranes have been discontinued by many leading retailers, leaving researchers with no tried and tested membrane available for use.
This project investigated both of these issues. Aquivion® and Nafion™ were evaluated across three key parameters – performance, degradation rate and hydrogen crossover - and compared against an unbranded commercially available membrane. The results showed that the use of a short side chain membrane did not significantly vary device operation across the three key parameters, and also showed the unbranded membrane to perform at levels similar to the branded membranes. Ex-situ characterisation revealed the presence of membrane degradation after device operation. Future experiments could see the unbranded membrane being tested at timescales required in an industrial electrolyser
H → b¯b decays in associated V H production using data from the ATLAS detector
Get PDFThis thesis covers my contribution to the V H(H → b ¯b) analysis conducted using 139 fb−1 of data collected by the ATLAS experiment at the LHC. I primarily focused on the boosted 2-lepton MVA analysis, training on new variables and optimizing hyperparameters and contributing to truth-flavour tagging studies. A set of analysis improvements, including those described in this thesis, improved the observed (expected) significance from 2.6 (3.4) to 4.1 (4.5) standard deviations in the 2-lepton region. My development work on the online trigger tool (TTWeb) is also outlined, including my contribution to preparing TTWeb for the start of Run 3 of the LHC
Accountability, self and the state: an extended case study in a Chinese public organisation
No full textAbstract not currently available
Simulation of tactile roughness using ultrasound haptics
Get PDFVirtual reality experiences can be made more immersive with the use of haptic technologies. However, the current methods rely on bulky controllers and gloves that only offer basic vibrations to differentiate textures. This thesis proposes a new approach that utilizes ultrasound haptics and various techniques to create a sense of roughness. The research conducted explores different parameters for inducing roughness and their compatibility with ultrasound haptics. A new technique for eliciting varying levels of roughness using basic patterns is also introduced. To compensate for the lack of physical object and textural information, two studies were conducted using audio and visual modalities. The findings reveal that basic patterns can successfully simulate roughness through ultrasound haptics, but some traditional roughness-inducing parameters do not work. Additionally, visuals have a minimal impact on roughness perception, and audio does not positively affect it
Advances in laser-free topographic control of the scanning thermal microscope
Get PDFScanning thermal microscopes typically employ the ‘beam bounce’ optical lever method to measure nano-scale deflection in their probes. This is a robust and simple approach for many experiments and has been the primary form of deflection measurement of atomic force microscope cantilevers since the 1980’s. However, illumination can have a significant impact on the behaviour of the probe or sample being studied. Examples include materials that have light-sensitive behaviour (e.g. semiconductors), and laser illumination creating an additional heat flux to the probe. The measurement of microstructures deflecting without employing optical methods has been addressed in commercial micro-electro-mechanical systems (MEMS) sensors, that typically employ strain gauges or capacitive approaches to measure the deflection of their mechanical sensing elements. This thesis looks to investigate the integration of self-deflection sensing into the SThM system for the purposes of topographic control. The inclusion of strain sensors, based on the electron tunnelling effect, onto the cantilever was explored using high-accuracy overlay alignment techniques developed in this work through novel iterations of the Penrose marker. This work also explores the already available SThM thermal signal as a means of “thermal feedback” topographic control of the microscope. Through the development of custom electronics and control techniques, combined thermal and topographic scans of topographic, thin film, and active semiconductor samples have been presented in air, under liquid, and in vacuum environments without cantilever illumination from an optical lever laser, showing vertical topographic resolutions greater than 5nm
Investigations of the magnesium chloride hexahydrate – magnesium hydride system for solid state hydrogen generation and storage
No full textAbstract not currently available
Synthesis of CDEF ring systems of hexacyclinic acid
Get PDFHexacyclinic acid is a polyketide isolated from Streptomyces cellulosae in 2000. It comprises a 5/6/5 fused ring system (A, B and C) connected to a bridged tricycle (D, E and F). Hexacyclinic has demonstrated some notable cytotoxic activities against cancer cells. CDEF ring system plays a crucial role in completing the synthesis of cytotoxic hexacyclinic acid. This strategy was proved to be more efficient than the previous one developed by our group. 4-Benzyl-3-propionylthiazolidine-2-thione 160 was prepared from (R)-phenylalanine through reduction, cyclisation, and nucleophilic substitution reaction. Additionally, 4-methylpenten-al 115 was also synthesised from ethyl 4- methylpent-4-enoate to yield an aldol 161, which was converted to aldehyde 162 over two steps and subsequently used to generate the DEF fragment in the next step
Coupling and conductivity: deciphering roles of the C-linker in Arabidopsis Kout channels
No full textAbstract not currently available
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