59,857 research outputs found
Dataset for support of thesis 'Development of Short-wave Infrared Fibre Lasers'
No full textThis dataset supports the University of Southampton Doctoral Thesis "Development of Short-wave Infrared Fibre Lasers".
This dataset contains:
Slope efficiencies and M2 for the key results presented in the thesis, raw data supporting the measurement of aluminium reflectivity, fibre design data
such as refractive index profiles and bend loss values determined in Optifiber, and data supporting the fabrication of a CMS
Associated publications:
M. Burns, P. Shardlow, T. Jefferson-Brain, P. Barua, J. Sahu, W. Clarkson, '47 W Continuous-wave 1726~nm thulium fiber laser core-pumped by an erbium fiber laser,' Optics Letters, vol. 44, no. 21, pp. 5230-5233, 2019.
M. Burns, P. Shardlow, W. Clarkson, 'Widely-tunable operation of a thulium doped fiber laser between 1654~nm and 2025~nm', CJ-7.4, CLEO Europe, 2021.
M Burns, P. Shardlow, P. Barua, T Jefferson-Brain, J. Sahu, W. Clarkson, '47~W 1726~nm operation of a thulium fiber laser pumped in-band by an erbium-only fiber laser', 112600G, SPIE Photonics West, LASE, 2020.
M. Burns, P. Shardlow, P. Barua, T. Jefferson-Brain, J. Sahu, W. Clarkson, 'Thulium-doped Fibre Laser with 25 W Single-mode Output at 1726 nm', CJ\_1\_2, CLEO Europe, 2019.
M. Burns, P. Shardlow, P. Barua, T. Jefferson-Brain, J. Sahu, W. Clarkson, 'High power 1726nm operation of a thulium fiber laser pumped in-band by an erbium-only fiber laser', 108970O, Photonics West, 2019.
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‘Wisselbare Woorde’
No full textCarrol Clarkson’s chapter wrestles with the contentious question of Coetzee’s relation to the Black Consciousness Movement in South Africa of the 1970s and early 1980s, which took its philosophical bearings from Frantz Fanon and found expression in the writings of Steve Biko. Clarkson focuses on the ways in which Coetzee departed from the ideas about writing and resistance that were circulating in his contemporary South Africa, particularly as articulated by novelist Nadine Gordimer. Clarkson discusses two related literary-critical problems: an ethics and politics of representation, and an ethics and politics of address, showing how Coetzee explores a tension between freedom of expression and responsibility to the other. In the slippage from saying to addressing we are led to further thought about modes and sites of consciousness—and hence accountabilities—in the interlocutory contact zones of the post-colony. The chapter invites a sharper appreciation of what a postcolonial philosophy might be.</p
Inclusive design diagnosis based on the ONS scales?
No full textDesigning for a wider range of population has recently been propagated by new design philosophies and approaches such as Universal Design, Design for All and Inclusive Design. Compared with the other two approaches, Inclusive Design approach seems to be more practical in that it provides a framework for implementation (Keates et al., 2000). It also features a gradual strategy, which incorporates a user capability range and takes into account the target population.
However, the lack of accessible inclusive design information still challenges Inclusive Design practice. In this early stage, Inclusive Design requires proper diagnosis that can address existing problems, as well as explore possible solutions. One of the crucial issues is to find a flexible evaluation method that can map users’ capability to product properties and vice versa.
The aim of this paper is to discuss the exploration of such an evaluation method and to present its feasibility
Circular output from a high power Nd:YLF slab laser
No full textNeodymium-doped Yttrium Lithium Fluoride (YLF) lasers have traditionally been power-limited by the relatively low tensile strength of the crystal. When power-scaling solid-state lasers, the choice of the gain media geometry, the doping level, and the pumping scheme is dictated by minimizing the impact of thermally induced stress. To date the slab architecture has been the most successful for scaling the average-power of Nd:YLF lasers due to its favorable thermal management. However, for efficient high-radiance laser action it is also necessary to have a good overlap between the cavity mode and the planar gain volume. We present the performance characteristics for an end-pumped slab-laser utilizing a stable low-loss resonator configuration that transforms a circular cavity mode at the output coupler into a very high aspect ratio elliptical beam in the slab gain element to match the pumped volume. The optical arrangement for transforming the beam shape is also suitable for a double-pass slab amplifier configuration. A polarized CW output power of 50W, on the weaker Nd:YLF 1053nm transition was obtained with a single slab gain element and 110W of incident pump power from three spatially multiplexed diode bars. Laser threshold was around 7W and the slope efficiency, with respect to incident power, 46%
Designing for inclusivity: Assessing the accessibility of everyday products
No full textThe older adult population in most developed countries is growing slowly, but continuously (Laslett, 1996). Several functional changes occur with age which may result in a decrease of perceptual, cognitive and motor skills (Smith et al., 2000). In spite of this well-known trend, designers continue to design instinctively for “ablebodied” young people (Coleman, 1997). The result is products that are generally difficult to be used by elderly citizens and people with disabilities (Keates et al., 2000). Clearly new inclusive design approaches are required to interpret and evaluate the range of functional capabilities of this sector of the population and include them into mainstream design. The aim of this paper is to present a range of potential methods for assessing product accessibility. Although these methods provide valuable feedback about a product’s accessibility, many of them lack the ability to be liked with actual population data. An alternative assessment method, structured assessment, is proposed which enables designers to quantify with reasonable accuracy the numbers of users excluded from product usage
Measurement of the ratio of prompt χ c to J / ψ production in pp collisions at √s = 7 TeV
No full textThe prompt production of charmonium χ c and J / ψ states is studied in proton-proton collisions at a centre-of-mass energy of √s = 7 TeV at the Large Hadron Collider. The χ c and J / ψ mesons are identified through their decays χ c → J / ψ γ and J / ψ → μ + μ - using 36 pb - 1 of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for χ c and J / ψ, σ (χ c → J / ψ γ) / σ (J / ψ), is determined as a function of the J / ψ transverse momentum in the range 2 < p T J / ψ < 15 GeV / c. The results are in excellent agreement with next-to-leading order non-relativistic expectations and show a significant discrepancy compared with the colour singlet model prediction at leading order, especially in the low p T J / ψ region
Energy transfer in lanthanide complexes
No full textThis thesis details investigations into the photophysical properties of lanthanide ions in a number of different systems. The preparation and characterisation of lanthanide containing surfactant salts of the type Ln(A0T)(_3) (Ln = Tb, Nd, Eu, AOT = bis-(2-ethylhexyl) sulfosuccinate) is described. Small angle neutron scattering experiments have been used to determine the size and shape of reverse micelles formed by these surfactants in water/cyclohexane microemulsions. The luminescence lifetimes of the lanthanide ions have been used to investigate the solvation environment within reverse micelle systems as a function of water content. The use of lanthanide complexes based on 1,4,7,10-tetraazacyclododecane bearing phenanthridine antenna in luminescence microscopy has been explored. Samples such as silica particles, onion skin cells and guinea pig heart cells have been imaged. Time- resolved measurements have allowed time gating of the sample from a fluorescent background and lifetime maps of the images have been obtained. The preparation and characterisation of deuteriated complexes of dota (1,4,7,10- tetraazacyclododecane-1,4,7,10-tetraacetic acid) with lanthanide ions is described. Selective deuteriation of both the ring and arm sites allow the relative quenching effects of C-H/D oscillators to be determined for various lanthanides in a series of structurally well defined complexes. Finally, investigations into the distance dependence of the energy transfer between aromatic chromophores and lanthanide ions have been undertaken. The synthesis of a model system linking a phenanthridine donor to a europium complex by poly(valine) spacer units is described. Preliminary photophysical results show that the quantum yield of emission by europium decreases as the distance between the donor acceptor pair is increased
Pattern and process of vegetation change (succession) in recent volcanic landscapes of New Zealand and Hawaii
No full textVolcanic activity (including lava flows, debris flows and tephra eruptions) is a regular feature of many landscapes of the North Island of New Zealand and the Hawaiian archipelago. Over the last 35 years, we have been using a combination of the chronosequence and direct monitoring methodologies (Clarkson 1998; Walker et al. 2010) to research the pattern and process of vegetation change (succession) in these landscapes. The following account summarizes pattern and process from our main study sites: Whakaari (White Island), Rangitoto Island, Mt Tarawera, Mt Ngauruhoe, Mt Ruapehu, and Mt Taranaki in New Zealand and Mauna Loa in Hawaii. The main focus of this account is forest development following significant eruptions
Letter from Carl Hayden to P. J Moran
No full textLetter from Carl T. Hayden to P. J. Moran concerning the alignment of the road to Bright Angel Trail
Letter from P. J. Moran to Carl Hayden
No full textLetter from P. J. Moran to Carl T. Hayden inquiring when construction will begin on the approach road to Bright Angel Trail
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