VictorJuiz/thesis huggingface dataset:
A millimeter unilateral finline SIS mixer with a wide IF bandwidth 

Superconductor-Insulator-Superconductor (SIS) tunnel junction mixers are now commonly used in as- tronomical receivers at (sub)millimeter wavelengths because of their superb sensitivity, high dynamic range and stability of operation. Niobium SIS mixers operating at frequencies well below the super- conducting gap (∼680 GHz) have already achieved quantum limited sensitivity. Therefore to further enhance the receiver sensitivity, increasing the Intermediate Frequency (IF) bandwidth of SIS mixers has became crucial. This thesis focuses on the theoretical modeling, design and experimental verifi- cation of Nb SIS mixers operating around 230 GHz with a wide IF bandwidth of 1–15 GHz. These mixers were designed for a single baseline heterodyne interferometer (GUBBINS), which is being built to observe the Sunyaev-Zel’dovich effect in the Cosmic Microwave Background. The combination of wide IF bandwidth SIS mixers and complex analogue correlators will allow GUBBINS to feature high surface brightness sensitivity, that helps to distinguish the weak SZ effect from the background noise. The SIS mixer detector system was assembled inside the GUBBINS cryostat together with the IF electronics and RF/LO optical systems. Low noise temperatures of around 71 K were then measured in the GUBBINS system.
The Nb SIS mixer we have developed uses a unilateral finline and fully integrated planar circuits deposited on a silicon substrate, to couple the electromagnetic radiation from the waveguide into the SIS junction. The finline mixer allows a broad-band RF coupling, an easy integration of the on-chip planar circuits and an easy-to-fabricate mixer block. To achieve a wide IF bandwidth, the output impedance of the SIS mixer was well matched to the input impedance of the amplifier by a multi-stage microstrip circuit. Additionally, the planar circuit of the SIS mixer was also designed to have a small lumped inductance and capacitance. The SIS mixer chip was extensively simulated by rigorous electromagnetic software (HFSS) and the S-parameter was exported to a quantum mixing package SuperMix to produce a full-wave model of the mixer. Experimental testing yielded a best noise temperature of 50 K with an average noise temperature of 75 K over an RF bandwidth of 160 GHz– 260 GHz. We have performed thorough experimental and computational investigation of the IF system in particular the constraints on the bandwidth caused by the lumped element capacitance of the mixer chip and the matching of the output impedance of the mixer to the IF amplifier. Our conclusion is that a bandwidth of 1–15 GHz could be achieved using our mixer design, subject to the performance of the amplifier. Finally, a variable temperature load system was successfully developed and tested inside the cryostat, to avoid the losses from the room-temperature optics. We have showed that the noise temperature of the SIS detector could be reduced by as much as 15 K by testing the mixer using a variable temperature load inside the cryostat.

Keywords: SIS tunnel junction
SIS mixer
Advisor: Yassin, G
Understanding the role of oxidation in bonding of aluminium alloys

The main aim of this work is to study the bonding behaviour of Al alloys as a function of temperature, time and processing conditions from a perspective of oxidation so as to gain a comprehensive knowledge of the oxidation issues during processing and to design better bonding approaches for different alloy systems.
Two major parts of work have been carried out during the study: (a) the use of a stacking approach and a double pouring approach to potentially join two Al alloys and their effectiveness are assessed; and (b) a precise investigation of the oxidation mechanisms for Al-Cu and Al-Mg alloys using a combination of theoretical analysis and experimental characterization.
The project started with the use of a stacking approach to try to bond two stacked Al alloys. The stacked sample can be viewed as a bi-metal which has an oxide bi-film layer at the bond interface. It was found that the bi-film layer was a physical barrier preventing direct metallic bonding. How this bi-film layer evolves during the bonding process was then investigated.
The work then moved on to investigate the oxidation mechanisms of Al-Cu alloys and Al-Mg alloys in greater detail. The thermodynamics, kinetics of oxidation, chemistry and morphology of the oxide scale were particularly studied. Briefly speaking, in the case of the Al-Cu-O2 system, the oxidation proceeds in the order of amorphous γ-Al2O3 - to - crystalline γ-Al2O3 - to - α-Al2O3; in the case of the Al-Mg-O2 system, the oxidation proceeds as amorphous γ-Al2O3 to MgO to MgAl2O4 and the morphology of the oxide scale develops from a protective layer to a porously structured composite layer.
A double pouring approach was finally developed to bond Al and Al-5Cu but the method has still not been perfected due to the formation of bi-film defects along the bond interface. Induction melting, squeeze casting, and extrusion bonding were therefore studied as an attempt to reduce the harmful effect of bi-film defects. Although all of the approaches exhibit some limitations, they have potential for future development.

Keywords: oxidation
Advisor: O‘Reilly, K
Galano, M
Mathematical models of glacier sliding and drumlin formation

One of the central difficulties in many models of glacier and ice sheet flow lies in the prescription of boundary conditions at the bed. Often, processes which occur there dominate the evolution of the ice mass as they control the speed at which the ice is able to slide over the bed. In part I of this thesis, we study two complications to classical models of glacier and ice sheet sliding. First, we focus on the effect of cavity formation on the sliding of a glacier over an undeformable, impermeable bed. Our results do not support the widely used sliding law ub=Cτ
p
b
N−q, but indicate that τb/N actually decreases with ub/N at high values of the latter, as suggested previously for simple periodic beds by Fowler (1986). The second problem studied is that of an ice stream whose motion is controlled by bed obstacles with wavelengths comparable to the thickness of ice. By contrast with classical sliding theory for ice of constant viscosity,the bulk flow velocity does not depend linearly on the driving stress. Indeed, the bulk flow velocity may even be a multi-valued function of driving stress and ice thickness. In the second part of the thesis, attention is turned to the formation of drumlins. The viscous till model of Hindmarsh (1998) and Fowler (2000) is analysed in some detail. It is shown that the model does not predict the formation of three-dimensional drumlins, but only that of two-dimensional features, which may be interpreted as Rogen moraines. A non-linear model allows the simulation of the predicted bedforms at finite amplitude. Results obtained indicate that the growth of bedforms invariably leads to cavitation. A model for travelling waves in the presence of cavitation is also developed, which shows that such travelling waves can indeed exist. Their shape is, however, unlike that of real bedforms, with a steep downstream face and no internal stratification. These results indicate that Hindmarsh and Fowler's model is probably not successful at describing the processes which lead to the formation of streamlined subglacial bedforms.
Reportage in the 'thirties

This investigation of the origins and impact of the 'new reportage' in the '30s interrogates the 'dominant tradition' of documentary, i.e. an 'objective' recording of facts and historical events, by reconstructing an alternative 'broken' tradition of radical reporting which was both 'counterfactual' and criticised the status of documents (including photographs and film) as privileged forms of realistic representation.
The implications of Russian Formalist 'defamiliarization' led to an avant-garde 'literature of fact' in the USSR and Weimar Germany, inspired by John Reed's Ten Days that Shook the World, with the potential not only to represent suppressed facts but to subvert 'automatized' concepts, thus challenging official paradigms defining historically significant data and putting the model of reality constructed by dominant ideology under strain, as the work of the LEF group and Egon Erwin Kisch shows. The new reportage was self- consciously mediating and 'bared its devices', often using montage to expose the construetedness of discourses. Hence the thesis maps the growth of a parallel alternative reportage in '30s Britain which did not simply resuscitate the realistic project of Naturalism but built on the Modernist legacy, examining in detail the work of Orwell, Sommerfield, Priestley, and Hanley among others.
The thesis focuses on prose forms of reportage, from individual I-witnessing in articles and autobiographies, to 'participant observation', documentary novels, encyclopaedism, Mass-Observation and photojournalism, outlining the historical and cultural factors which gave reportage literary prominence at the time, as well as issues, such as unemployment, poverty and Appeasement, which it represented. Consequently, it explores the ways and means by which new reporters expressed their awareness of connections between political and cultural representation, in order to question authorized representations of fact and the sanctioned national self-image.
Active colloids and polymer translocation

This thesis considers two areas of research in non-equilibrium soft matter at the mesoscale.
In the first part we introduce active colloids in the context of active matter and focus on the particular case of phoretic colloids. The general theory of phoresis is presented along with an expression for the phoretic velocity of a colloid and its rotational diffusion in two and three dimensions. We introduce a model for thermally active colloids that absorb light and emit heat and propel through thermophoresis. Using this model we develop the equations of motion for their collective dynamics and consider excluded volume through a lattice gas formalism. Solutions to the thermoattractive collective dynamics are studied in one dimension analytically and numerically. A few numerical results are presented for the collective dynamics in two dimensions. We simulate an unconfined system of thermally active colloids under directed illumination with simple projection based geometric optics.
This system self-organises into a comet-like swarm and exhibits a wide range of non- equilibrium phenomena. In the second part we review the background of polymer translocation, including key experiments, theoretical progress and simulation studies. We present, discuss and use a common model to investigate the potential of patterned nanopores for stochastic sensing and identification of polynucleotides and other heteropolymers. Three pore patterns are characterised in terms of the response of a homopolymer with varying attractive affinity. This is extended to simple periodic block co-polymer heterostructures and a model device is proposed and demonstrated with two stochastic sensing algorithms. We find that mul- tiple sequential measurements of the translocation time is sufficient for identification with high accuracy. Motivated by fluctuating biological channels and the prospect of frequency based selectivity we investigate the response of a homopolymer through a pore that has a time dependent geometry. We show that a time dependent mobility can capture many features of the frequency response.

Keywords: swimmers
polymer dynamics
active colloids
simulation
stochastic sensing
colloids
phoresis
polymer translocation
fokker-planck equation
langevin equation
Advisor: Golestanian, R
Revisiting the 40,000 BP crisis in Iberia

This thesis focuses on the Mid/Upper Palaeolithic Transition in the Iberian Peninsula, and questions whether this process took place as hitherto widely claimed, by testing the validity of the traditional characteristics said to portray this event throughout Europe.
Research was carried out at different levels: old archaeological collections from two transitional sites (Abric Romani and Reclau Viver), previously unstudied, were systematically analysed and specific organic components (perforated shells) were radiocarbon dated. A thorough bibliographic database including information on these and all other Iberian sites was complied, in order to extend the study. The theoretical perspective of the topic was also investigated, to assess epistemological factors which are so often overlooked in this field of study. The socio-political events that have marked Spain and Portugal's contemporary histories, were also studied, since they played a crucial role in shaping Palaeolithic Research in both countries.
The so-called '40,000 BP Crisis', specifically located in northern Iberia, was revisited by studying not only the traditional sites which have produced chronometric readings around that date, but also others in the same region whose transitional layers have yielded much younger dates, to see if that phenomenon really existed or has been created by generalisations that have masked vital - but ultimately uncomfortable - information.
The study of this event is also placed into the peninsular and the wider European contexts, an exercise that has disclosed the vast complexity of the Transition, in terms of both the actual archaeological record and the theoretical interpretations that have been presented so far.
Ultimately, this research calls for a revision of some of the theoretical perspectives of Palaeolithic archaeologists, as well as far more careful site and regional-level research, in order to redress the abundant misconceptions that distort our understanding of the Transition process.

Advisor: Roe, D
‘Dark, mysterious, and undocumented’: the middlebrow fantasy and the fantastic middlebrow

The concept of ‘middlebrow’ literature in the twentieth century, which received minimal critical attention from the Leavises onwards, has recently become a site of literary and sociological interest, especially regarding the interwar period. This thesis considers the ways in which a corporate middlebrow identity, amongst an intangible community of like-minded readers, was affected by a popularity of the fantastic in the 1920s and 1930s. This subgenre, which I term the ‘domestic fantastic’ (in which one or more elements of the fantastic intrude into an otherwise normalised domestic world) allowed middlebrow authors and readers to focalise and interrogate anxieties affecting the status of the home and its inhabitants which were otherwise either too taboo or, conversely, too well-worn for a traditional, non-fantastic examination. This fantastic vogue was largely initiated by the success of David Garnett’s metamorphosis novel Lady Into Fox (1922), which prepared the way for the other novels discussed in this thesis, predominantly Sylvia Townsend Warner’s Lolly Willowes (1926), Elinor Wylie’s The Venetian Glass Nephew (1926), Ronald Fraser’s Flower Phantoms (1926), Edith Olivier’s The Love-Child (1927), John Collier’s His Monkey Wife (1930) and Green Thoughts (1932), and Frank Baker’s Miss Hargreaves (1940). Through the lenses of metamorphosis, creation, and witchcraft, these novels respond to and reformulate contemporary debates concerning sexuality in marriage, childlessness, and autonomous space for unmarried women. The ‘middlebrow fantasy’ of the stable, idealised home was being revealed as untenable, and the fantastic responded. During the interwar years, when assessments of British society were being widely recalibrated, the domestic fantastic was a subgenre which produced a select but significant range of novels which (whether playful or poignant, hopeful or tragic, nostalgic or progressive) provided the means for both author and reader to interrogate and comment upon the most pervading middle-class social anxieties, in unusual and revitalising ways.

Keywords: middlebrow
fantastic literature
twentieth-century literature
spinsters
sexuality
Advisor: Bayley, S
Perceptions of gender and the divine in Greek texts of the second and third centuries A.D

This thesis investigates the construction and reflection of gender identities in the religious sphere, namely the gods, their worshippers, and the rituals which link them. Religiously-interested Greek texts written by Artemidoros, Pausanias, Plutarch and Heliodoros in the second and third centuries A.D. form the basis of four chapter- studies. The introduction explores how deploying gender as a tool for investigating the texts reveals the author's own perceptions of how male and female operate within his discourse, and considers how these perceptions relate to the world beyond the text.
Chapter two examines Artemidoros' Interpretation of Dreams: his analytical system of dream interpretation reveals contemporary thought patterns. Artemidoros places striking reliance on gender in his structuring of divine and human power, and employs two differing divine models of gender, which have significant implications for the social construction of human gender. Chapter three emphasizes Pausanias' fascination with the marvellous in his Guide to Greece, and focuses on why he considers female priests more noteworthy than male. The problematic sexuality of female priests is frequently his focus in descriptions of myth and rite.
The fourth chapter considers Plutarch's Pythian dialogues and Isis and Osiris. It is the marriage-like nature of their relationship with their gods that makes both human and divine females perfect mediators between worshippers and their male god, the Pythia with Apollo, and Isis with Osiris. Chapter five finds a middle way between opposing views that Heliodoros' An Ethiopian Story is either a religious mystery text or entertainment without religious meaning. It focuses on how the relationship between the two lovers, Theagenes and Charikleia, is patterned by their relationship to their gods, Apollo and Artemis.
The concluding chapter draws out the significance of gendered hierarchy amongst the gods, and the importance of gender in the role and function of priests and prophets. It also considers the implications of the thesis' findings and approach for Jewish and Christian texts of the same period.
Religious autonomy and the personal law system

This thesis examines the Indian system of personal laws (‘the PLS’), under which the state applies a version of religious doctrine to the family matters of citizens whom it identifies as belonging to different religious groups. There has been a lengthy and persistent debate over the PLS, particularly in relation to its discriminatory effects upon women. However, another problem with the PLS has been little commented-upon. Supporters of the PLS emphasise its positive impact on religious freedom to such an extent that there is a pervasive assumption that the PLS is, indeed, good for religious freedom. But there has been surprisingly little critical assessment of the truth of this claim in either academic or political debates. This thesis, a work of applied normative legal theory, attempts to fill this important gap in the literature on the PLS. The thesis addresses the question of how the PLS affects one conception of religious freedom, namely religious autonomy. Its principal findings are that the PLS interferes with the religious autonomy of those subject to it by affecting their religious options (by interfering with their freedom from religion and their freedom to practice religion) and by harming their self-respect (by discriminating on the grounds of sex and religion, and by misrecognising their religious identities). Furthermore, the thesis finds that the PLS cannot be defended in the name of religious autonomy based on the possibility of exit from the system, the advantage of having the ‘option of personal law’, the power it gives people to bind their future selves, the expressive potential of the personal laws, the contribution it makes to membership in a religious community, the contribution it makes to religious group autonomy, or the recognition or validation it provides for religious identities. These conclusions imply that concerns relating to religious autonomy constitute an important set of objections to the PLS. The thesis then considers several reform proposals, including certain modifications of the PLS, a move towards a millet system, ‘internal’ reform of individual personal laws and the introduction of a Uniform Civil Code. It particularly focusses on one reform possibility – religious alternative dispute resolution – which has not been considered closely in the Indian context.

Keywords: religious arbitration
personal law
religious tribunals
personal status
religious freedom
law and religion
India
multiculturalism
South Asia
Advisor: Green, L
Ghanea, N
Khaitan, T
A new level of gene regulation: establishing a genome-wide role for antisense transcription

Transcription lies at the centre of gene expression. In eukaryotes, transcription occurs not only at genes but also across the non-coding portion of the genome, an apparently pervasive process that gives rise to a wide array of different transcripts. In recent years, it has emerged that genes themselves are frequently subject to non-coding transcription of their antisense strand. This antisense transcription is evident in eukaryotes from yeast to mammals; however its general genome-wide role, if indeed it has one, remains elusive. Here, the nature of antisense transcription in the budding yeast Saccharomyces cerevisiae is explored on a genome-wide scale. Antisense transcription is ubiquitous and often abundant, and appears to be driven by a promoter architecture at the 3’ end of genes, one which shows evidence of regulation, and which mirrors that found at the 5’ end. Furthermore, antisense transcription shows evidence of changing gene behaviour. It is associated with a drastically altered chromatin environment at the 5’ promoter and across the gene body; however it is not associated with a change in the level of gene transcription itself. Rather, these chromatin changes appear to enforce a change in the mode of gene transcription, promoting rapid bursts of transcription re-initiation that result in noisier gene expression – a hitherto unknown role of antisense transcription. It is proposed that antisense transcription represents a fundamental layer of gene regulation, and that it should be considered a canonical feature of eukaryotic genes.

Keywords: transcription
gene regulation
non-coding RNAs
antisense transcription
Advisor: Mellor, J
Monte carlo computing applied to x-ray room design

Currently, x-ray rooms are designed by employing measured scatter and transmission data obtained nearly thirty years ago. Subsequently, there is a clear need to reevaluate this information as the use of modern equipment is becoming increasingly common. For example, x-ray tubes with medium frequency generators are replacing single phase units. Recent literature has re-evaluated transmission data. However, the scatter found in x-ray rooms has not been studied in detail.
Two programs using Monte Carlo techniques have been developed for this purpose. The first program models the x-ray room including a slab phantom simulating the patient, a DAP meter, air and the room walls. The second program implements a realistic model of a patient in the imaging system. The results of the two programs have been validated by comparison with each other and by measurements.
The results confirm that the patient is the primary source of scatter in a x-ray room. However, large variations in the scatter values are observed for different x-ray examinations and when the imaging parameters are changed. The results also show that there is a significant scatter contribution from other materials in the primary xray beam including the air, DAP meter and x-ray collimators. The first program has been used to calculate the scatter at a door positioned behind a protective screen at the radiographer's console. It predicts that no shielding in the door is required for the imaging system investigated.
Therefore, a valuable computational tool has been developed which will aid the decision process in the design of clinical x-ray rooms.