109 research outputs found
Affective issues in learning technologies: emotional responses to technology and technology's role in supporting socio-emotional skills
This paper focuses on some of the author's research studies over the past thirty years and places these in a wider context to reflect on research into affective issues in learning technologies over this period, and to consider whether and how the issues uncovered by research have changed as technologies have developed over time. Three issues are given particular attention: firstly the reasons for learners' use or lack of use of technologies for their learning; secondly adult learners' attitudes towards using technology for learning and thirdly how technology might support socio-emotional development and expression in children. The discussion of these issues is framed by two of the author's research projects. For the first two issues this is an early study of students' perceptions and attitudes towards using computers for tutorial learning in 1980. The factors that influenced the students' use of the computer tutorials are discussed (including access, assessment and anxiety about using computers) and also the extent to which some of these factors persist for many learners using (or not using) technologies today. The discussion of the third issue draws on a series of studies conducted in the 1990s to investigate whether educational technology could support children and young people's emotional expression and communication and development of socio-emotional skills. Finally the paper considers how these kinds of issues have been taken forward and how they are represented in contemporary research and suggests that trust is an important factor in using learning technologies
An integrated optofluidic Bragg grating device to measure the dynamic composition of a fluid
Strong transitional mixing effects were observed by a planar Bragg grating sensor within a microfluidic system. This property was used to develop an integrated optofluidic sensor for detection of the composition of mixed solvent systems
Optofluidic integrated Bragg grating chemical sensor: Utilising a sodium-elective receptor surface to enhance detection
Planar waveguides can be written with a UV-laser into photosensitised silica to produce a wide range of optical devices. Careful modulation of two interfering beams allows Bragg gratings to be directly written into the channel. These Bragg gratings are inherently sensitive to temperature and strain, however etching away the surface exposes the mode within the grating to its surroundings. The corresponding observed shift in Bragg wavelength can be used to detect changes in this environment [1]. It has been previously reported [2] that the sensitivity of such a refractometer can be enhanced by over an order of magnitude through use of a high-index overlayer of tantalum pentoxide. This enhanced sensor has shown the potential to detect a single molecular monolayer upon the sensor surface [2]. This sensitivity was confirmed through the successful attachment and detection of a single molecular monolayer of a fluorescein-based organic dye to the sensor surface [3
An integrated Bragg grating oxygen sensor using a hydrophobic sol-gel layer doped with an organic dye
Oxygen sensing is required for the understanding of many chemical processes across a diverse set of fields including medicine, environmental science and chemical synthesis. Oxygen sensing can be achieved through the use of electronic sensors. However, there are limitations associated with electronic sensors including susceptibility to electromagnetic interference and presenting a spark risk in flammable environments. Optical fiber and integrated optical chemical sensors overcome these limitations of electrical based sensing methods
An integrated reconfigurable Bragg grating utilising a photoresponsive co-polymer
Reconfigurable Bragg grating devices are of significant interest for telecomm applications. Such devices can be fabricated by combining a UV-written silica Bragg grating with an azobenzene-based polymer - a photoresponsive material that undergoes reversible refractive index change on exposure to ultraviolet light. The preliminary 17 GHz tuning response suggests future applicability
Integrated planar Bragg grating oxygen sensor
We demonstrate an integrated planar Bragg grating sensor for the detection of oxygen by modification of the surface with a silica sol-gel containing immobilized methylene blue
Integrated temperature compensated Bragg grating refractometer
UV written planar Bragg grating sensors have been shown to form effective refractometers. Here we show that by using the birefringence of an integrated waveguide a temperature insensitive Bragg grating refractometer can be realised
Asymptotic Capture-Number and Island-Size Distributions for One-Dimensional Irreversible Submonolayer Growth
Using a set of evolution equations [J.G. Amar {\it et al}, Phys. Rev. Lett.
{\bf 86}, 3092 (2001)] for the average gap-size between islands, we calculate
analytically the asymptotic scaled capture-number distribution (CND) for
one-dimensional irreversible submonolayer growth of point islands. The
predicted asymptotic CND is in reasonably good agreement with kinetic
Monte-Carlo (KMC) results and leads to a \textit{non-divergent asymptotic}
scaled island-size distribution (ISD). We then show that a slight modification
of our analytical form leads to an analytic expression for the asymptotic CND
and a resulting asymptotic ISD which are in excellent agreement with KMC
simulations. We also show that in the asymptotic limit the self-averaging
property of the capture zones holds exactly while the asymptotic scaled gap
distribution is equal to the scaled CND.Comment: 4 pages, 1 figure, submitted to Phys. Rev.
Integrated Bragg grating sensors: achieving chemical sensing in liquid and gas flow systems
The sensing of chemical species is required within a diverse set of fields including industry, environmental monitoring and homeland security. The sensing of chemicals in liquid and gaseous environments has been traditionally achieved by electronic and electrochemical sensors. However, optical sensors demonstrate many benefits over these electronic systems, including remote interrogation of large sensor arrays via optical fibre and telecoms equipment, immunity from EM interference and absence of spark risk in flammable environments
Optofluidic Bragg Grating Sensor for Monolayer Detection
An exposed Bragg grating incorporated into a planar waveguide was used to form a refractive index sensor. The high sensitivity to subtle changes allowed the study of surface functionalisation and binding within a microfluidic system
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