60419 research outputs found
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Odour treatment in sewage treatment works
No full textBiotrickling filtration (BTF) of malodours from Sewage Treatment Works, is investigated in detail, as the most economical and environmentally friendly air treatment option. Experimental data were produced on the removal of H2S and VOCs by a Biotrickling filter (BTF) demonstration plant, namely a SULPHUSTM, which was installed by Thames Water in late 2015.
The two widely used models of Ottengraf and van den Over (1983) for BTFs were found to be inadequate with Root Mean Squared Errors (RMSE) of 22 and 4.8 mg m-3 of H2S respectively. These models are based on zero-order kinetics in the biofilm. Neither of these two existing models accounts for the possibility of diffusion limitation emerging at a point within the bed height; therefore, a novel hybrid model was developed for this possibility, which failed to improve the fit provided by the existing zero-order models. This confirms that the zero-order kinetics assumption is main source of error. The Michaelis Menten (M-M) kinetic model, predicts that zero-order is likely to be inaccurate at low pollutant concentrations when the kinetics should asymptote to fist order kinetics. However, first-order kinetics, which is found in the literature on BTFs, also fails to follow the trend of the data with RMSE of 0.36 mg m-3. A novel derivation based on the M-M kinetics is found to fit the data better the rest of the models with RMSE of 0.26 mg m-3. All models were also compared to the total VOC removal for the SULPHUSTM trial, and the M-M equation was also found to provide the best fit.
In the SULPHUSTM unit used in the trials, the product of the retention time and the specific surface area was higher than typically practiced. Thus, whilst the inlet concentration reached values too high for the first-order model, the concentration in most of the bed had been reduced low enough to render the zero-order model inaccurate.
The zero-order models provide a good fit to some of the laboratory H2S data by others at lower Empty Bed Retention Times (EBRT) and higher inlet concentrations than our case study. The zero order model fitting results of these data sets and the model fitting of the M-M model to our data all produced reaction rate constants of about 0.3 g/m3/s. This advance in the mathematical modelling of bio-tricking filtration has made it possible to demonstrate consistency in a seemingly disparate sets of experimental data within the biological air pollutant removal literature
The UK Higher Education Senior Management Survey: a statactivist response to managerialist governance
No full textIn this paper we present results from an extensive survey of United Kingdom (UK) university academics investigating satisfaction with senior managers and
university governance: the Senior Management Survey (SMS). 5,888 academic staff across the United Kingdom Higher Education (HE) sector completed the survey, and results were used to construct a league table of
staff satisfaction with management. This table is a stark indictment of the current state of the UK HE sector, showing a mean satisfaction score of
10.54%. The SMS also collected qualitative data, and we extend the league table’s insights using this data. Thematic analysis revealed seven major
themes: the dominance and brutality of metrics; excessive workload; governance and accountability; perpetual change; vanity projects; the silenced academic; work and mental health. We conclude with a discussion of
how this statactivist research can be used to bring about change in management and governance of UK HE
Investigation of the interaction of European porcine reproductive and respiratory syndrome virus with porcine antigen-presenting cells: implications for pathogenesis and immunity
No full textPorcine reproductive and respiratory syndrome viruses (PRRSV) cause the most economically significant disease of swine. The emergence of highly pathogenic strains and the limitations of current vaccines pose significant challenges to PRRS control. An improved understanding of pathogenesis is needed to support the development of improved vaccines. Experimental infection with virulent PRRSV-1 subtype 3 strains is associated with enhanced immune responses, which have been attributed to the more effective viral clearance compared to ‘typical’ PRRSV-1 subtype 1 strains. Previous ex vivo data has also shown that this increased virulence correlates with a broader cell tropism for cells of the myeloid lineage. The causation of this correlation was investigated by assessing whether European PRRSV-1 strains can infect dendritic cells (DC), which are not canonically a target cell. A staining strategy was optimised to enrich and phenotype blood-derived DC (BDC) subsets. Infection experiments demonstrated that BDC were not susceptible, and that cytokine responses in enriched BDC culture were suppressed by inoculation of subtype 3 strain Lena. Further characterisations of host responses instead used monocyte-derived macrophages (MΦ) and DC. Functional assays determined that pro-inflammatory responses were increased by subtype 3 strain SU1-Bel more than subtype 1 strains, including modulation of surface activation markers, ability to prime allogeneic T cell proliferation, and secretion of inflammatory cytokines; Lena, however, did not induce pro-inflammatory cytokine responses but decreased endocytic and phagocytic capacity. This trend was validated by transcriptomic analysis of infected monocyte-derived MΦ, which identified putative genes of interest for future studies, including pattern recognition receptors. Inflammasome treatments suggested that SU1-Bel primed inflammasome activation and that subtype 3 strain replication was decreased by inflammasome inhibition, proportionately increasing MΦ viability. Finally, preliminary trials of a novel macrophage cell line demonstrated its utility for further investigation of the mechanistic basis for the enhanced virulence of PRRSV-1 subtype 3 strains
“Incubated entrepreneurs”: a study into the everyday experiences of business incubation through a micro-sociological lens
No full textBusiness incubation has grown in popularity over recent decades. Reviewing the incubation
literature revealed that little attention had been paid to the experiences of the incubated
entrepreneurs (the human dimension) themselves or to the social aspects (the social dimension)
of the incubation process. This was identified as a significant gap in the literature, given the
intense nature of the incubation experience for entrepreneurs and its potential implications for
their business development. To explore this neglected ‘social dimension’ of incubation, the
Thesis utilised a provisional theoretical framework derived from micro-sociology (Interaction
Ritual Chain Theory, Impression Management and Framing) to capture the contextual,
interpersonal and individual levels of incubator experience. This framework was
operationalised through a qualitative/ethnographic investigation using semi-structured
interviews, overt-observations and Participant-Led Photography within three business
incubator sites which were part of a larger incubator organisation. The unit of analysis and
focus of this research was the incubatee (the entrepreneur) within the incubator setting. As such
21 entrepreneurs were purposively sampled across these incubators. The resulting data analysis
was informed partly by questions deriving from the theoretical framework and partly by an
openness to emergent themes and issues generated inductively from the data. The findings
revealed across all three incubator sites that organisational practices, especially around
membership and spatial layout, created barriers to social interaction. Where intense energy
forming interaction was observed among members, it tended to be in small working groups in
co-located working spaces. Organisational practices to stimulate social engagement proved
relatively ineffective. The research findings provide important insights into business
incubation’s social aspect, thereby advancing the limited extant knowledge in this area and
extending existing understandings about entrepreneurs’ everyday incubator lives. The value
this research brings to existing knowledge and literature on entrepreneurship and incubation is
that, for the first known time, the views of the participants (the incubated entrepreneurs
5
themselves), has been inductively captured as they journey the incubation process in a rich and
meaningful way. Thus, the research contributes to theory by advancing and adapting detailed
understanding of Collins’ (2004) model of Interaction Ritual Chain Theory (Collins, 2004). It
also adds to methodological understanding of inductive approaches, particularly regarding the
adoption of Participant-Led-Photography in entrepreneurship research. Its contribution to
practice is to recognise for the first-time incubator social dynamics that can impact
entrepreneurs, particularly within an incubator setting
The garden of perfect brightness & playing in the garden of perfect brightness: historical fiction as a ‘playframe.’
No full textCreative: The Garden of Perfect Brightness
Set in 1700s China, at the court of the Qing dynasty, this historical novel focuses on the life of Giuseppe Castiglione, a painter recruited by the Jesuits to serve in their Mission in Beijing. As Castiglione struggles artistically in an unfamiliar culture, he finds himself drawn to Niuhuru, concubine to a prince and mother to a future emperor, who lives in the Yuan Ming Yuan, the Garden of Perfect Brightness, a country estate. Told in alternate chapters, the novel follows the relationship between the two and the changes made to the Garden. Castiglione is tasked with being the architect who will turn the simple country retreat into an imperial wonderland as Niuhuru sees her home turn into a place she no longer recognises.
Critical: Playing in the Garden of Perfect Brightness
David Harlan asks why reviewers of historical novels ‘almost never (venture) beyond the most obvious questions of factual accuracy.’ In this thesis I propose that historical fiction can be seen as a ‘playframe’, an idea transposed from Jackson and Kidd’s work in heritage performance (e.g. setting a play about slavery within a museum on the topic), where the framework of a historical setting and the playful exploration of a fictional element combine to create what author Hannah Kent calls ‘work(s) of possibility,’ resulting in strong audience/reader engagement.
I propose the word playframe as a hybrid concept for a hybrid genre. Using the framework of history, the fictional element of the narrative can then be seen as a playful engagement with the past, whereby an author pursues their own concept or vision. Rather than exclusively focusing on factual accuracy, I suggest that we should also pay attention to what an author has chosen to ‘play’ with, rather than potentially dismissing the fictional element as a historically inaccurate intrusion. I have identified three types of authors and named them the Ventriloquist, the Mosaic-Maker and the Magician, for their different approaches to playing with the past.
Whatever their choice, my argument is the same: in choosing to write or read a novel in this hybrid genre rather than, say, a textbook of history, the experience should be one of playful engagement and exploration rather than exclusively interrogating for accuracy. ‘The museum does not have all the answers. The museum plays a potentially far more important role… it has questions,’ suggests Bradburne. I would argue that the same is true of historical fiction, and that we should value and explore the fictional element as well as the historical in this hybrid genre
Frailty in transition? Troubling the norms, boundaries and limitations of transition theory and practice
No full textThis article focuses on ‘transition’ and how it is understood within higher education. Drawing on data from concept map-mediated interviews at two institutions, we examine the conceptions of transition held by academic and professional staff, who work to support students’ learning into and through higher education. We suggest that normative understandings of transition often draw upon a grand-narrative that orchestrates and reiterates a stereotypic understanding of students’ experiences. Often this narrative involves students’ interpellation into a field of discourse where the subject is constructed as both homogeneous and in deficit: ill-prepared, lacking in independence, as vulnerable and in need of support. However, this study suggests that beneath this discourse lies a more nuanced picture: one where students’ experiences can be conceptualised as diverse and fluid. Moreover, we employ the concept of pedagogic ‘frailty’ to expose the significance of the environments and wider contexts in which students ‘transition’, and to explore the impact of systemic tensions upon students’ experiences. This article further argues that future research should shift discussions away from the deficits of students, and examine how we can make underlying environmental and systemic challenges more explicit, in order to widen our understanding and discussions of these constraints
Loss of phenotypic inheritance associated with ydcI mutation leads to increased frequency of small, slow persisters in Escherichia coli
No full textWhenever a genetically homogenous population of bacterial cells is exposed to antibiotics, a tiny fraction of cells survives the treatment,the phenomenon known as bacterial persistence [G.L. Hobby et al.,
Exp. Biol. Med. 50, 281–285 (1942); J. Bigger, The Lancet 244, 497–
500 (1944)]. Despite its biomedical relevance, the origin of the phenomenon is still unknown, and as a rare, phenotypically resistant subpopulation, persisters are notoriously hard to study and define.
Using computerized tracking we show that persisters are small at birth and slowly replicating. We also determine that the highpersister mutant strain of Escherichia coli, HipQ, is associated with the phenotype of reduced phenotypic inheritance (RPI). We identify the gene responsible for RPI, ydcI, which encodes a transcription
factor, and propose a mechanism whereby loss of phenotypic inheritance causes increased frequency of persisters. These results provide insight into the generation and maintenance of phenotypic
variation and provide potential targets for the development of therapeutic strategies that tackle persistence in bacterial infections
New Radio Numerology and Waveform Evaluation for Satellite Integration into 5G Terrestrial Network
No full textThis paper analyses the New Radio (NR) air interface
waveforms and numerologies in the context of current
activities and studies of 3GPP related to the feasibility and standardisation of necessary adaptations for the 5G NR to support integrated-satellite-terrestrial networks with low earth orbit (LEO) satellites. Frequency-localized orthogonal frequency
division multiplexing (OFDM)-based candidate waveforms are recommended by 3GPP as the waveforms for the NR in order to preserve the advantages of OFDM as well as maintain backward compatibility. 5G New Radio enables diverse service support, efficient synchronization and channel adaptability using a multinumerology
concept, which defines a family of parameters of the
parent waveform, that are related to each other by scaling. The major design challenges in the LEO satellite scenario are power limited link budget and high Doppler effects which can be addressed by choosing waveforms with small peak to average power ratio (PAPR) and sub-carrier bandwidth adaptation respectively.
Hence, the selection of the right waveform and numerology is of prime relevance for the proper adaptation of 5G NR for LEO satellite terrestrial integration. The performance evaluation of the new air interface waveforms, with different numerologies, are
carried out under the effect of carrier frequency offset (CFO), multipath effects, non-linearity, phase noise and additive white Gaussian noise (AWGN)
Advanced Transceiver Processing for Large MIMO Systems
No full textLarge MIMO base stations remain among wireless systems designers’ best tools for increasing wireless through-put while serving many clients. Still, current system designs, sacrifice throughput with simple linear MIMO detection algorithms. Higher performance detection techniques are known, but remain off the table because of their related complexity and latency requirements.
In this PhD thesis, novel signal processing approaches are presented, that have the potential to reclaim this wasted MIMO channel capacity while meeting challenging latency requirements by employing parallel processing and efficient tree pruning techniques. The core of this work builds a novel framework for massively parallel signal processing for large MIMO systems applicable to both uplink and downlink. The proposed approaches are asymptoticly optimal, adapt to the processing capabilities of the base station and the current MIMO channel realization, support powerful a posteriori probability (APP) decoding and have latency requirements similar to simple successive interference cancellation. The proposed massively parallel precoder and the detector are validated in over-the-air experiments. In order to make the approaches practical, novel solutions for fast rate adaptation (for both uplink and downlink) are proposed, necessary to translate the improved detection/precoding capabilities into actual throughput.
In addition, this thesis introduces the novel principle of Antipodal detection and decoding, that enables the complexity efficient demultiplexing of tens of interfering streams even in the most challenging transmission scenarios (e.g., when the number of transmitted streams equals the number of the base stations antennas). For the first time, the proposed Antipodal detector leverages the unexploited relation between the detection reliability and the detection complexity of sphere decoding to extract implicit reliability information (at no extra processing cost) and to substantially reduce the detection complexity itself. In particular, the detector polarizes its output into highly reliable bits and erasures. While a traditional belief-propagation decoder can handle such an outcome, the Antipodal decoder proposed is tailored to the properties of the Antipodal detector output
Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation
No full textThe mixed caesium and formamidinium lead triiodide perovskite system (Cs1−xFAxPbI3) in the form of quantum dots (QDs) offers a pathway towards stable perovskite-based photovoltaics and optoelectronics. However, it remains challenging to synthesize such multinary QDs with desirable properties for high-performance QD solar cells (QDSCs). Here we report an effective oleic acid (OA) ligand-assisted cation-exchange strategy that allows controllable synthesis of Cs1−xFAxPbI3 QDs across the whole composition range (x = 0–1), which is inaccessible in large-grain polycrystalline thin films. In an OA-rich environment, the cross-exchange of cations is facilitated, enabling rapid formation of Cs1−xFAxPbI3 QDs with reduced defect density. The hero Cs0.5FA0.5PbI3 QDSC achieves a certified record power conversion efficiency (PCE) of 16.6% with negligible hysteresis. We further demonstrate that the QD devices exhibit substantially enhanced photostability compared with their thin-film counterparts because of suppressed phase segregation, and they retain 94% of the original PCE under continuous 1-sun illumination for 600 h
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