878 resultados para thin client
Resumo:
An optically transparent thin-layer electrochemical (OTTLE) cell with a locally extended optical path has been developed in order to perform vibrational circular dichroism (VCD) spectroscopy on chiral molecules prepared in specific oxidation states by means of electrochemical reduction or oxidation. The new design of the electrochemical cell successfully addresses the technical challenges involved in achieving sufficient infrared absorption. The VCD-OTTLE cell proves to be a valuable tool for the investigation of chiral redox-active molecules.
Resumo:
Self-consistent field theory (SCFT) is used to study the step edges that occur in thin films of lamellar-forming diblock copolymer, when the surfaces each have an affinity for one of the polymer components. We examine film morphologies consisting of a stack of ν continuous monolayers and one semi-infinite bilayer, the edge of which creates the step. The line tension of each step morphology is evaluated and phase diagrams are constructed showing the conditions under which the various morphologies are stable. The predicted behavior is then compared to experiment. Interestingly, our atomic force microscopy (AFM) images of terraced films reveal a distinct change in the character of the steps with increasing ν, which is qualitatively consistent with our SCFT phase diagrams. Direct quantitative comparisons are not possible because the SCFT is not yet able to probe the large polymer/air surface tensions characteristic of experiment.
Resumo:
Lipid cubic phases are complex nanostructures that form naturally in a variety of biological systems, with applications including drug delivery and nanotemplating. Most X-ray scattering studies on lipid cubic phases have used unoriented polydomain samples as either bulk gels or suspensions of micrometer-sized cubosomes. We present a method of investigating cubic phases in a new form, as supported thin films that can be analyzed using grazing incidence small-angle X-ray scattering (GISAXS). We present GISAXS data on three lipid systems: phytantriol and two grades of monoolein (research and industrial). The use of thin films brings a number of advantages. First, the samples exhibit a high degree of uniaxial orientation about the substrate normal. Second, the new morphology allows precise control of the substrate mesophase geometry and lattice parameter using a controlled temperature and humidity environment, and we demonstrate the controllable formation of oriented diamond and gyroid inverse bicontinuous cubic along with lamellar phases. Finally, the thin film morphology allows the induction of reversible phase transitions between these mesophase structures by changes in humidity on subminute time scales, and we present timeresolved GISAXS data monitoring these transformations.
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Currently, infrared filters for astronomical telescopes and satellite radiometers are based on multilayer thin film stacks of alternating high and low refractive index materials. However, the choice of suitable layer materials is limited and this places limitations on the filter performance that can be achieved. The ability to design materials with arbitrary refractive index allows for filter performance to be greatly increased but also increases the complexity of design. Here a differential algorithm was used as a method for optimised design of filters with arbitrary refractive indices, and then materials are designed to these specifications as mono-materials with sub wavelength structures using Bruggeman’s effective material approximation (EMA).
Resumo:
This publication is a full colour bi-lingual catalogue for the exhibition Thin Place, curated by Ciara Healy for Oriel Myrddin. It includes artwork by five interdisciplinary artists based in West Wales, the West of Ireland and London. The exhibition, symposium and education programme, funded by the Arts Council of Wales aims to show how the fields of art, literature, science and theology are interconnected, especially when considering the nature of reality, the concept of an otherworld and the prospect of an afterlife. Included in the catalogue are texts especially commissioned for the exhibition by professionals who work in disciplines outside of the art world. It also includes an introductory essay by Ciara Healy.
Resumo:
The research which underpins this paper began as a doctoral project exploring archaic beliefs concerning Otherworlds and Thin Places in two particular landscapes - the West Coast of Wales and the West Coast of Ireland. A Thin Place is an ancient Celtic Christian term used to describe a marginal, liminal realm, beyond everyday human experience and perception, where mortals could pass into the Otherworld more readily, or make contact with those in the Otherworld more willingly. To encounter a Thin Place in ancient folklore was significant because it engendered a state of alertness, an awakening to what the theologian John O’ Donohue (2004: 49) called “the primal affection.” These complex notions and terms will be further explored in this paper in relation to Education. Thin Teaching is a pedagogical approach which offers students the space to ruminate on the possibility that their existence can be more and can mean more than the categories they believed they belonged to or felt they should inhabit. Central to the argument then, is that certain places and their inhabitants can become revitalised by sensitively considered teaching methodologies. This raises interesting questions about the role spirituality plays in teaching practice as a tool for healing in the twenty first century.
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Sensitive optical detection of nitroaromatic vapours with diketo-pyrrolopyrrole thin films is reported for the first time and the impact of thin film crystal structure and morphology on fluorescence quenching behaviour demonstrated.
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Do philosophers use intuitions? Should philosophers use intuitions? Can philosophical methods (where intuitions are concerned) be improved upon? In order to answer these questions we need to have some idea of how we should go about answering them. I defend a way of going about methodology of intuitions: a metamethodology. I claim the following: (i) we should approach methodological questions about intuitions with a thin conception of intuitions in mind; (ii) we should carve intuitions finely; and, (iii) we should carve to a grain to which we are sensitive in our everyday philosophising. The reason is that, unless we do so, we don’t get what we want from philosophical methodology. I argue that what we want is information that will aid us in formulating practical advice concerning how to do philosophy responsibly/well/better.
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This paper reports the first derived thermo-optical properties for vacuum deposited infrared thin films embedded in multilayers. These properties were extracted from the temperature-dependence of manufactured narrow bandpass filters across the 4-17 µm mid-infrared wavelength region. Using a repository of spaceflight multi-cavity bandpass filters, the thermo-optical expansion coefficients of PbTe and ZnSe were determined across an elevated temperature range 20-160 ºC. Embedded ZnSe films showed thermo-optical properties similar to reported bulk values, whilst the embedded PbTe films of lower optical density, deviate from reference literature sources. Detailed knowledge of derived coefficients is essential to the multilayer design of temperature-invariant narrow bandpass filters for use in non-cooled infrared detection systems. We further present manufacture of the first reported temperature-invariant multi-cavity narrow bandpass filter utilizing PbS chalcogenide layer material.
Resumo:
Thin Place is an interdisciplinary project which aims to find connections between the fields of art, archaeology, astrophysics, astrology, alternative therapy, poetry and theology. The nature of this project goes beyond the exhibition and incorporates a symposium, catalogue and education programme which will attempt to dissolve the boundaries that separate fields of knowledge and, in so doing, create a thin place at Oriel Myrddin. The five exhibiting artists and the other contributors to this project have produced work that is concerned with or responds to two particular locations: West Wales and the West of Ireland. In ancient times it was believed that the West was where departed souls easily entered Otherworlds. This is because the delineation between worlds was more permeable along these coasts. Archaeological excavations reveal that West Wales and the West of Ireland were thought by some to be ‘thin places.’ In considering the notion of a ‘thin place’, this exhibition addresses the ways in which we value our relationship with Place, particularly in landscapes where human and non-human relationships are well established.
Resumo:
Accurate knowledge of ice-production rates within the marginal ice zones of the Arctic Ocean requires monitoring of the thin-ice distribution within polynyas. The thickness of the ice layer controls the heat loss and hence the new-ice formation. An established thinice algorithm using high-resolution MODIS data allows deriving the ice-thickness distribution within polynyas. The average uncertainty is ±4.7 cm for ice thicknesses below 0.2 m. In this study, the ice-thickness distributions within the Laptev Sea polynya for the two winter seasons 2007/08 and 2008/09 are calculated. Then, a new method is applied to determine a daily MODIS thin-ice product.
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There is a widespread assumption that clients’ expectations should be accommodated during a building project. However, there may be conflicting expectations within a client organization and these may change over time in the course of a project. Actor-Network Theory (ANT) is used to study the incorporation of client expectations into the on-going development of a building project. To illustrate this, negotiations over a particular decision, namely the location of a building on one university campus was analysed. Negotiations went through a number of stages, involving a master plan architect, members of the public, campus maps and the Vice Chancellor. An ANT analysis helped to trace diverse actors' interests in a series of discussions and how these interests conflict with each other as one option was chosen over another. The analysis revealed new client interests in each negotiation process. Also, the prioritisation of client interests changed over time. The documentation of diverse and dynamic client interests especially contributes to the understanding of how some client interests fail to be incorporated in decision-making processes
Resumo:
Many construction professionals and policy-makers would agree that client expectations should be accommodated during a building project. However, this aspiration is not easy to deal with as there may be conflicting interests within a client organization and these may change over time in the course of a project. This research asks why some client interests, and not others, are incorporated into the development of a building project. Actor-Network Theory (ANT) is used to study a single building project on a University campus. The building project is analysed as a number of discussions and negotiations, in which actors persuade each other to choose one solution over another. The analysis traces dynamic client engagement in decision-making processes as available options became increasingly constrained. However, this relative loss of control was countered by clients who continued the control over the timing of participants' involvement, and thus the way to impose their interests even at the later stage of the project.