2,652 research outputs found
Pickering, James D., March 13, 1995 [Interview]
No full textProfessor of English and former Dean James D. Pickering was interviewed on March 13, 1995, by Michael Birkner about his career at Gettysburg College, including memories of colleagues, classes, and students.Langsam, Walter C.; Mason, Francis C.; Geyer, Richard B.; Lindeman, Ralph D.; Pickering, Anne; Bloom, Robert L.; Crapster, Basil L.; Glatfelter, Charles H.; Mara, Richard T.; Barnes, Robert D.; Sundermyer, William K.; Warthen, George S.; Wolfinger, Joseph K.; Baskerville, Edward J.; Hanson, Henry W.A.; Paul, Willard S.; Hartzell, Mildred H.; Zagars, Waldemar; Tilberg, Wilbur E.; Dunn, Seymour B.; Shainline, John W.; Storek, Martha; Jones, W. Ramsey; Frying, Robert H.; Rice, John S.; Ziegler, Earl E.; Schubart, W. Richard; Bream, Henry T.; Kramer, Frank H.; Bowen, Earl; Zinn, John B.; Held, C. Robert; Ahrens, Frederick C.; Hinrichs, Donald W.; Packard, Bruce L.; Glassick, Charles E.; Williams, Frank B.; Hoffman, F. Stanley; Potts, David B.; Taylor, Katherine K.Walter C. Langsam Years; Willard S. Paul Years; Carl Arnold Hanson Years; Charles E. Glassick Year
'No Witnesses. No Leads, No Problems': The Reenactment of Crime and Rebellion
No full textOpened in 1841, the foreboding buildings which comprised Melbourne's first penitentiary were extended several times until the completion of the bluestone walls and turrets in 1864. Although its design was inspired by the fashionable reformist ideas in penology of the day, the prison regime practiced within the heavy walls also incorporated a stark reminder of the lingering 'bloody code' that had characterised the British justice for centuries. Before it was closed in 1929 the prison had been the site of 136 executions. Among a grim list of offenders, the most notorious individual to die in the prison was Edward (Ned) Kelly. At 10:00 am on 11 November 1880, Kelly, his arms pinioned with a heavy leather strap, a white cloth bag folded back on his forehead, was led from a holding cell adjacent to the gallows. Outside a crowd estimated at between 4000 and 8000 had gathered. Although it had been over three years since an execution in Old Melbourne Gaol, it was not morbid curiosity which drew them there. These were Kelly's supporters (and opponents of capital punishment) who had hastily collected a petition bearing 30,000 signatures seeking a commutation of the sentence of death in the short interregnum between the court case and the day of execution. The numbers (neither crowd nor petition), however, could not disguise the fact that many Victorians supported the punishment of Kelly to the full extent of the law
Fundamental aspects of Pickering emulsion stabilisation
No full textMuch research has been carried out in recent years on Pickering emulsions, but
understanding of the underlying physics requires considerable strengthening. This
thesis seeks to address several fundamental aspects by presenting the results of
recent experimental work.
This work has focused on a model oil-in-water emulsion system stabilised by
fluorescent colloidal silica particles and using a mixture of dodecane and isopropyl
myristate as the oil phase. The phase behaviour of the particle dispersions has
been altered using sodium chloride and sodium iodide, whilst sodium hydroxide
and hydrochloric acid have been used to adjust the pH of samples. Comparisons
are also made to emulsions stabilised by commercially available fumed silica.
Conventionally, it was assumed that a weakly flocculating particle dispersion is
required in order to generate a stable Pickering emulsion. It is shown in this
work, however, that in some circumstances a weakly flocculating dispersion leads
to the least stable emulsion. It is therefore argued that a more nuanced view
of Pickering stabilisation is required, taking into account the factors affecting
whether particles will adsorb to the interface during emulsification.
Very recently it has begun to be suspected that Pickering emulsions sometimes
aggregate due to the sharing of particles between two droplets, an effect known
as bridging. In this thesis it is also shown that particle bridges can form in
Pickering emulsions at high shear, and that they can subsequently be broken by
low shear or by modifying the particle wettability. For the first time, electron
microscopy has been used to provide direct evidence of droplets sharing particles.
A simple theoretical model is developed, based on collisions between partially
coated droplets, which captures the trends observed experimentally. It is argued
that particle bridging may have been overlooked in the literature, and that the
shear history of emulsions is a crucial determinant of subsequent behaviour.
The deaggregation of bridged emulsions has been studied using a novel method
where two different colours of particles are used. By starting with two emulsions
which are bridged, each stabilised by a different colour of particle, and then using
confocal microscopy to study them as they are mixed together and deaggregate,
the processes involved in deaggregation can be elucidated. These experiments
have also shown, for the first time, the dynamic nature of particles in Pickering
emulsions; particles transfer readily between droplets when the samples are placed
on a roller bank. It is found that a period of unbridging and rebridging takes
place prior to deaggregation of the emulsions, and the timescale of deaggregation
can be tuned by varying the particle wettability.
The two-colour method has also been applied to the study of Pickering emulsions
which are repeatedly sheared. It is found that limited coalescence is not reestablished
simply by re-applying the shear rate which was used in the initial
emulsification. This behaviour is attributed to the presence of an elastic shell of
particles at the interface, which inhibits droplet breakup, and is in contrast to that
of surfactant-stabilised emulsions, where increasing the stabiliser concentration
makes droplets more liable to deform and breakup.
Finally, a short study has been carried out attempting to increase the scale of
the experiments presented in this thesis to sample volumes of approximately one
litre. This study has demonstrated the relevance of particle bridging to industrial
emulsification processes.
Overall, experiments with carefully controlled model Pickering emulsions, including
those using two colours of particles, have revealed the fundamental workings
of these arrested systems
Mediated behavioural change in human-machine networks: Exploring network characteristics, trust and motivation
No full textHuman-machine networks pervade much of contemporary life. Network change is the product of structural modifications and not just participant relations. Taking citizen participation as an example, engagement with relevant stakeholders reveals trust and motivation to be the major objectives for the whole network. Using a typology to describe network state based on multiple characteristic or dimensions, we can predict possible behavioural outcomes in the network. However, this has to be mediated via attitude change rather than material or reputational reward predicted by social exchange models. Motivation for the citizen participation network can only increase in line with enhanced trust. The focus for changing network dynamics, therefore, shifts to the dimensional changes needed to encourage increased trust. It turns out that the coordinated manipulation of multiple dimensions is needed to bring about the desired shift in attitude
Roadmap for human-machine networks for Citizen Participation
No full textThis white paper presents a roadmap for human-machine networks for Citizen Participation. Based on a quantitative survey of 20 self-selecting stakeholders, key issues across stakeholders were identified along with potential conflicts between them. The challenges of developing and maintaining trust along with keeping motivation going are discussed. These are addressed in the first instance with manipulation of dimensions derived from the HUMANE typology to suggest ways in which conflict between stakeholders might be addressed. Finally, returning to the main concerns of trust and motivation, a non-linear timeline is proposed based on activities affecting HMNs and how such events might affect trust
From Realism to the Affective Turn: An Agenda
No full textEver since the late eighteenth century when new forms of visual entertainment claimed to be able to use technology to replicate or simulate the literal details of nature, scholars, poets and intellectuals have bemoaned the increasing dominance of the realist aesthetic. Classicists such as Sir Joshua Reynolds and Romantics such as Samuel Coleridge found the practice of literalist simulation to be debased and disgusting. It demanded merely mechanical competence, eliminated the vital creative role of the artist�s idealising imagination, and appealed to uncultivated tastes attracted by the sensational wonders of the technical facsimile. Art lost its age-old raison d��tre if it became indistinguishable from literal nature
Impacts of hunter-gatherers on the vegetation history of the eastern vale of pickering, Yorkshire
No full textResearch is undertaken into the vegetation and human impact at three previously un-researched archaeological sites from the eastern Vale of Pickering. The vegetation history is reconstructed from the end of the Windermere Interstadial c. 13,000 (^14)C yr BP until the final Mesolithic c. 5100 (^14)C yr BP. The early Mesolithic human impact on the vegetation is assessed using a three stage statistical test to establish the internal variability in the data as well as background variations in pollen output. The results reveal that humans had a small but significant impact on the vegetation around two of the sites. Pollen preservation at the third site precluded analyses of the impacts of humans on the vegetation. The three-stage test used to test for human impact was quite successful but requires revision before any further use. On the whole the tests confirmed the findings of conventional human impact analyses. During the pre-Holocene fires occurred on a regular basis. These fires varied in location and intensity, suggesting that some of the fires were regional or large-scale, whilst others were small and very localized. A multi-causal explanation has been given for the fires. Later, during the early Mesolithic, human groups are thought to have burnt the reedswamp at the lake edges as part of an economic strategy. Star Carr is the only site that demonstrates clearance of significant areas of woodland. During the later Mesolithic the hunter-gatherers have a greater impact on the vegetation within the Vale. This is attributed to the need for more resources as a result of vegetation change and increased population levels. Unlike their counter-parts from the North York Moors, the occupants of the lowland Vale of Pickering cause no long-term change to their environment
Investigation of Pickering emulsion systems to overcome compositional ripening in reduced-calorie snack-food water-in-oil systems
No full textAs regulations and consumer desire for healthier dietary options increases, there is
a growing interest in producing foods with reduced calorie content. One approach
is to replace the high-calorie components with water in the form of water-inoil
emulsions. However, food microstructures are metastable and so prone to
collapse, resulting in very short lived emulsions with water migrating out of the
droplets. This can be due to coalescence, Ostwald ripening, or, if there are other
species that can mix with the water, compositional ripening.
In the past few decades, particle-stabilised (Pickering) emulsions have garnered
great interest due to their unique characteristics. These are due to the interface
becoming rigid when stabilised with colloids, as opposed to surfactants, resulting
in increased stability against coalescence and Ostwald ripening. This thesis aims
to investigate the feasibility of using Pickering emulsions as a solution to the
challenge of compositional ripening.
To study Pickering emulsions, fluorescent confocal microscopy was utilised to
separate and observe the various components. An image analysis pipeline was
developed and used with confocal microscopy to track and characterise the
evolution of the emulsions over time.
As a model Pickering system, water-in-dodecane emulsions stabilised by colloidal
particles were initially explored. Similar emulsions were fabricated with various
concentrations of sugar in the aqueous phase, and combined with the pure water
emulsions. This provided a means of varying the chemical potential difference
between the two droplet species, with the water migrating from pure water
droplets to sugar-filled ones. To explore the effects of modifying the continuous
phase, dodecane was replaced with tributyrin, a short-chain triglyceride found in
many foods. In both systems, it was found that the rate of ripening increases with
sugar concentrations, with the tributyrin system ripening faster than dodecane,
as expected. Interestingly, it was observed that droplets ‘explode’ in dodecane
but remain as crumpled states in tributyrin. Evidence that water remains in these
crumpled states hints towards a means of overcoming compositional ripening.
Following this two further modifications to the model system were investigated. In
the first instance, the dodecane system was modified with the addition of toluene
once the particles were adsorbed to the interface. The goal of this approach
was that the addition of toluene degrades the colloid steric stabiliser, inducing
an attractive Van der Waals force between them, creating a more rigid colloidal
monolayer. Interestingly, a new end-fate for these droplets was observed, where
they slowly fall apart and result in empty broken filaments and sheets. To better
understand this behaviour, a recently developed contactless interfacial rheology
setup was used to determine the effects of added toluene to the properties of
the colloidal interface. In the second instance, the colloid surface chemistry was
altered by changing the type of steric stabiliser, inspired by literature indicating
differences in the interaction potential for these colloids at oil-water interfaces.
Different end states were observed, including crumpled droplets with long-term
stability, depending on the size and steric stabilisation of the colloids as well as
the aqueous phase they are stabilising
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