Temporal Capitalism: How Time Shapes Democracy Under Capitalism

This thesis uses a Marxist analysis of capitalism to better understand the relationship between capitalism and democracy by specifically looking at the way in which capitalism distributes control over time. With centralization of time under the control of capitalist employers the outcome of liberal democratic inputs is naturally skewed towards the owning class, and against the working class. Understanding time this way offers a route to its politicization and can serve as an argument against the seeming neutrality of capitalism by making explicit the fact that its core logic is oppositional and alien to a truly democratic society

Temporal Capitalism: How Time Shapes Democracy Under Capitalism

This thesis uses a Marxist analysis of capitalism to better understand the relationship between capitalism and democracy by specifically looking at the way in which capitalism distributes control over time. With centralization of time under the control of capitalist employers the outcome of liberal democratic inputs is naturally skewed towards the owning class, and against the working class. Understanding time this way offers a route to its politicization and can serve as an argument against the seeming neutrality of capitalism by making explicit the fact that its core logic is oppositional and alien to a truly democratic society

Low‐Field Actuating Magnetic Elastomer Membranes Characterized using Fibre‐Optic Interferometry

Smart robotic devices remotely powered by magnetic field have emerged as versatile tools for wide biomedical applications. Soft magnetic elastomer (ME) composite membranes with high flexibility and responsiveness are frequently incorporated to enable local actuation for wireless sensing or cargo delivery. However, the fabrication of thin ME membranes with good control in geometry and uniformity remains challenging, as well as the optimization of their actuating performances under low fields (milli‐Tesla). In this work, the development of ME membranes comprising of low‐cost magnetic powder and highly soft elastomer through a simple template‐assisted doctor blading approach, is reported. The fabricated ME membranes are controllable in size (up to centimetre‐scale), thickness (tens of microns) and high particle loading (up to 70 wt.%). Conflicting trade‐off effects of particle concentration upon magnetic responsiveness and mechanical stiffness are investigated and found to be balanced off as it exceeds 60 wt.%. A highly sensitive fibre‐optic interferometric sensing system and a customized fibre‐ferrule‐membrane probe are first proposed to enable dynamic actuation and real‐time displacement characterization. Free‐standing ME membranes are magnetically excited under low field down to 2 mT, and optically monitored with nanometer accuracy. The fast and consistent responses of ME membranes showcase their promising biomedical applications in nanoscale actuation and sensing

Chemically treated 3D printed polymer scaffolds for biomineral formation

We present the synthesis of nylon-12 scaffolds by 3D printing and demonstrate their versatility as matrices for cell growth, differentiation, and biomineral formation. We demonstrate that the porous nature of the printed parts makes them ideal for the direct incorporation of preformed nanomaterials or material precursors, leading to nanocomposites with very different properties and environments for cell growth. Additives such as those derived from sources such as tetraethyl orthosilicate applied at a low temperature promote successful cell growth, due partly to the high surface area of the porous matrix. The incorporation of presynthesized iron oxide nanoparticles led to a material that showed rapid heating in response to an applied ac magnetic field, an excellent property for use in gene expression and, with further improvement, chemical-free sterilization. These methods also avoid changing polymer feedstocks and contaminating or even damaging commonly used selective laser sintering printers. The chemically treated 3D printed matrices presented herein have great potential for use in addressing current issues surrounding bone grafting, implants, and skeletal repair, and a wide variety of possible incorporated material combinations could impact many other areas

Efficiently texturing hierarchical superhydrophobic fluoride-free translucent films by AACVD with excellent durability and self-cleaning ability

Translucent and superhydrophobic glass surfaces were fabricated by one-step deposition of a composite from the precursors, polydimethylsiloxane (PDMS) and tetraethyl orthosilicate (TEOS), via aerosol-assisted chemical vapour deposition. A raspberry-like hierarchical structure was obtained due to the nanoparticles being decomposed by the TEOS precursor and deposited around the micro-scale particles formed by the hydrolysis of the PDMS precursor. In this work, a translucent and superhydrophobic film was prepared by using optimized parameters (T: 290–330 °C, deposition time: 15–30 min) and the resulting water contact angle and sliding angle were >160° and <1°, respectively. It was found that there were 9 bounce cycles when water droplets were dropped onto such surfaces. Superior robustness was observed against tape-peeling, and on exposure to UV light (365 nm, 3.7 mW cm−2, 72 h) and to a large pH range (pH = 1–14, 72 h). The mechanical robustness was also examined and the results demonstrated that the film loses its superhydrophobicity when abraded for 5 meters with coarse sandpaper. The self-cleaning test demonstrated that the superhydrophobic surface could shed various contaminants and aqueous dyes, leaving a clear surface behind. This novel method can be applied to various substrates, including flexible (fabric and copper mesh) and rigid materials (copper block). This can provide a new, rapid and facile route for producing large-scale samples with multifunctional applications

Low‐field actuating magnetic elastomer membranes characterized using fibre‐optic interferometry

Smart robotic devices remotely powered by magnetic field have emerged as versatile tools for wide biomedical applications. Soft magnetic elastomer (ME) composite membranes with high flexibility and responsiveness are frequently incorporated to enable local actuation for wireless sensing or cargo delivery. However, the fabrication of thin ME membranes with good control in geometry and uniformity remains challenging, as well as the optimization of their actuating performances under low fields (milli‐Tesla). In this work, the development of ME membranes comprising of low‐cost magnetic powder and highly soft elastomer through a simple template‐assisted doctor blading approach, is reported. The fabricated ME membranes are controllable in size (up to centimetre‐scale), thickness (tens of microns) and high particle loading (up to 70 wt.%). Conflicting trade‐off effects of particle concentration upon magnetic responsiveness and mechanical stiffness are investigated and found to be balanced off as it exceeds 60 wt.%. A highly sensitive fibre‐optic interferometric sensing system and a customized fibre‐ferrule‐membrane probe are first proposed to enable dynamic actuation and real‐time displacement characterization. Free‐standing ME membranes are magnetically excited under low field down to 2 mT, and optically monitored with nanometer accuracy. The fast and consistent responses of ME membranes showcase their promising biomedical applications in nanoscale actuation and sensing

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Photocatalytic thin films : their characterisation and antimicrobial properties

This thesis is concerned with the synthesis and characterisation of TiO2 based photocatalyst thin films and the assessment of their antimicrobial properties. When exposed to light of wavelength less than 380 nm TiO2 films can demonstrate self-cleaning and self-disinfecting properties. This is due to photocatalytic processes occurring on the film surface resulting in film superhydrophilicity and reactive oxygen species (ROS) production. These ROS and radicals readily oxidise organic pollutants and microbes adherent to the material surface. Consequently, TiO2 thin films are of great research interest as self-cleaning, antimicrobial coatings. TiO2 and doped TiO2 materials were prepared by a simple sol-gel route from titanium n-butoxide as the principle precursor material. Film deposition was carried out using a dip-coating technique, with substrates withdrawn from the precursor sol at a fixed speed. Deposited films were calcined to produce crystalline thin films, with excellent adherence to the substrate (glass slides). Films were characterised using a number of analytical techniques including UV-visible spectroscopy, X-ray diffraction, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy and EXAFS/XANES. Photocatalysis and film hydrophilicity were investigated using established methods. Stearic acid photodegradation, monitored by FT-IR was used to assess film photocatalysis, by monitoring the peak areas of the C-H stretching region. Relative film hydrophilicities were determined by measuring the contact angle of a sessile droplet of water. Antimicrobial properties of the films were assessed with typical examples of Gram- positive and Gram-negative organisms. Staphylococcus aureus (NCTC 6571) and Escherichia coli (NCTC 10418) were selected. Films demonstrated microbicidal activity against both organisms under 365nm UV illumination, and under illumination by a typical hospital lamp (28W 2-D fluorescent). Microbial adhesion to various substrates was also examined, using a dip-blot method. Films produced in this study demonstrate excellent potential as durable surface coatings with significant antimicrobial activity against microbes of clinical importance.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

On the Use of Hydroxyl Radical Kinetics to Assess the Number-Average Molecular Weight of Dissolved Organic Matter

Dissolved organic matter (DOM) is involved in numerous environmental processes, and its molecular size is important in many of these processes, such as DOM bioavailability, DOM sorptive capacity, and the formation of disinfection byproducts during water treatment. The size and size distribution of the molecules composing DOM remains an open question. In this contribution, an indirect method to assess the average size of DOM is described, which is based on the reaction of hydroxyl radical (HO^•) quenching by DOM. HO^• is often assumed to be relatively unselective, reacting with nearly all organic molecules with similar rate constants. Literature values for HO^• reaction with organic molecules were surveyed to assess the unselectivity of DOM and to determine a representative quenching rate constant (<i>k</i>_rep = 5.6 × 10⁹ M^–1 s^–1). This value was used to assess the average molecular weight of various humic and fulvic acid isolates as model DOM, using literature HO^• quenching constants, <i>k</i>_C,_DOM. The results obtained by this method were compared with previous estimates of average molecular weight. The average molecular weight (<i>M</i>_n) values obtained with this approach are lower than the <i>M</i>_n measured by other techniques such as size exclusion chromatography (SEC), vapor pressure osmometry (VPO), and flow field fractionation (FFF). This suggests that DOM is an especially good quencher for HO^•, reacting at rates close to the diffusion-control limit. It was further observed that humic acids generally react faster than fulvic acids. The high reactivity of humic acids toward HO^• is in line with the antioxidant properties of DOM. The benefit of this method is that it provides a firm upper bound on the average molecular weight of DOM, based on the kinetic limits of the HO^• reaction. The results indicate low average molecular weight values, which is most consistent with the recent understanding of DOM. A possible DOM size distribution is discussed to reconcile the small nature of DOM with the large-molecule behavior observed in other studies