A study of the impact of technology-enhanced learning on student academic performance.

In university education a lot of emphasis is placed on the use of the virtual learning environment (VLE) in teaching to enhance the student learning experience. As a result, the academic staff is encouraged to use VLEs in different ways, including as a platform to provide online access to the study material but also as a source of additional online module activities aimed at enhancing student learning. This article reports on a study conducted on 257 students to investigate whether the utilisation of VLE has any impact on the final marks achieved by the students. As part of the study, the VLE logs were contrasted with the final marks of the students participating in a Law Module (LM), an Electrical Engineering Module (EEM) and a Mechanical Engineering Module (MEM) delivered at Edinburgh Napier University in the academic year 2013/14. The results showed that the number of VLE visits did not have a direct impact on the final marks obtained by the students. However, for one of the modules there was some correlation between the final marks obtained by the students and the way the modules were structured around the VLE. The results of the study emphasised the need for continued improvement of the technology-enhanced teaching and learning skills of the academic staff in order to enhance the student learning experience

Textile carbon reinforcement structures with integrated optical fibre sensors designed for SHM applications

An optical fibre-based strain sensor embroidered to a functionalised carbon structure (FCS) that can be used for structural health monitoring (SHM) is introduced. The aim of the design is not only to monitor strain, but also to act as a structural strengthening mechanism in the target application. The integration of optical fibres on the FCS is achieved by "interweaving" the two elements on a polymer textile infstrate in a grid formation using a specialised fabrication process. The thus obtained sensor was then characterised using a fibre optic Mach-Zehnder (MZ) interferometric setup where a variation in the fibre length, i.e. resulting from strain, would induce a variation in the interference pattern. To do so, two different functionalised skein samples (incorporating optical fibres) were infjected to varying elongation using a tensile testing machine by carefully incrementing the applied force. A good correlation between the applied force and measured length change was observed, showing the value of the dual-achievement of the proposed optical fibre-based mechanism in obtaining strain measurement while being utilised as a strengthening agent. © 2017 SPIE.BMBF/03ZZ034

Intensity-modulated PM-PCF Sagnac loop in a DWDM setup for strain measurement

A novel intensity-modulated Sagnac loop sensor based on polarization-maintaining photonic crystal fiber (PM-PCF) in a setup with a dense wavelength division multiplexer (DWDM) for strain measurement is presented. The sensor head is made of PM-PCF spliced to single-mode fibers. The interferometer spectrum shifts in response to the longitudinal strain experienced by the PM-PCF.After passing the Sagnac loop, light is transmitted by a selected DWDM channel, resulting in a change in the output optical power due to the elongation of PM-PCF. Hence, appropriate adjustment ofspectral characteristics of the DWDM channel and the PM-PCF Sagnac interferometer is required. However, the proposed setup utilizes an optical power measurement scheme, simultaneouslyomitting expensive and complex optical spectrum analyzers. An additional feature is the possibility of multiplexing of the PM-PCF Sagnac loop in order to create a fiber optic sensor network

Optical Fibre Refractive Index Sensor in a Hybrid Fibre Grating Configuration

A temperature compensated Refractive Index (RI) sensor incorporating a Long Period Grating (LPG) and a Fibre Bragg Grating (FBG) in a series configuration has been developed and evaluated. The LPG was used as a RI sensor allowing it to respond to external RI variations while the FBG was used for temperature compensation. The LPG and FBG wavelengths were chosen to be within suitable spectral bandwidths for efficient interpretation of both RI and temperature. The performance of the hybrid sensor was evaluated for use as a chemical sensor by varying sodium chloride (NaCl) concentrations in water from 0.25 – 2%NaCl and temperature from 10-95 oC and by recording its corresponding attenuation band shifts. The sensitivity of the hybrid sensor to NaCl concentration and temperature is calculated to be 0.61 nm/%NaCl and 8 pm/oC respectively

Evaluation of Viscosity Dependence of the Critical Meniscus Height with Optical Fiber Sensors

Conventional means of data extraction using optical fiber interrogators are not adequate for fast-paced detection of a target parameter. In this instance, the relationship between the critical meniscus heights (CMH) of several liquids to the extraction speed of a rod submerged in them, have been analyzed. A limitation of a previous interrogator used for the purpose had been light absorption by the liquid due to the used bandwidth of the readily-available light source, i.e., C-band. The newly proposed technique addresses this limitation by utilizing a broadband light source instead, with a Si-photodetector and an Arduino. In addition, the Arduino is capable of extracting data at a relatively faster rate with respect to the conventional optical interrogator. The use of a different operational wavelength (850 nm instead of 1550 nm) increased the r2 and the sensitivity of the sensor. The new setup can measure surface chemistry properties, with the advantage of being comparatively cheaper than the conventionally available interrogator units, thereby providing a suitable alternative to conventional measurement techniques of liquid surface properties, while reducing material waste, i.e., in terms of the required volume for detection of a target parameter, through the use of optical fiber

Fiber Optic Sensors Embedded in Textile-Reinforced Concrete for Smart Structural Health Monitoring: A Review

The last decade has seen rapid developments in the areas of carbon fiber technology, additive manufacturing technology, sensor engineering, i.e., wearables, and new structural reinforcement techniques. These developments, although from different areas, have collectively paved way for concrete structures with non-corrosive reinforcement and in-built sensors. Therefore, the purpose of this effort is to bridge the gap between civil engineering and sensor engineering communities through an overview on the up-to-date technological advances in both sectors, with a special focus on textile reinforced concrete embedded with fiber optic sensors. The introduction section highlights the importance of reducing the carbon footprint resulting from the building industry and how this could be effectively achieved by the use of state-of-the-art reinforcement techniques. Added to these benefits would be the implementations on infrastructure monitoring for the safe operation of structures through their entire lifespan by utilizing sensors, specifically, fiber optic sensors. The paper presents an extensive description on fiber optic sensor engineering that enables the incorporation of sensors into the reinforcement mechanism of a structure at its manufacturing stage, enabling effective monitoring and a wider range of capabilities when compared to conventional means of structural health monitoring. In future, these developments, when combined with artificial intelligence concepts, will lead to distributed sensor networks for smart monitoring applications, particularly enabling such distributed networks to be implemented/embedded at their manufacturing stage

Graphene-Oxide and Hydrogel Coated FBG-Based pH Sensor for Biomedical Applications

A hydrogel coated fibre grating-based pH sensor for biomedical applications has been realised, where Graphene Oxide (GO) had been used to enhance the bonding between the coating and the fibre. Two methods of deposition of GO were analysed i.e., evaporation and co-electroplating. The paper concludes that the system of GO evaporated on the fibre + the hydrogel has a sensitivity much higher, (6.1 ± 0.5) pm/pH, than the system of Cu and GO co-electroplated + the hydrogel, (1.9 ± 0.1) pm/pH, for a pH range between 2 to 10. The other conclusion is that the first system has a less coating bonding energy with the optical fibre whereas the second system has a stronger bonding energy, with better durability

Editorial on Special Issue “Modern Applications in Optics and Photonics: From Sensing and Analytics to Communication”

Note: In lieu of an abstract, this is an excerpt from the first page.Optics and photonics are among the key technologies of the 21st century and offer the potential for novel applications in areas as diverse as sensing and spectroscopy, analytics, monitoring, biomedical imaging and diagnostics, as well as optical communication technology, among others [...

Fibre Grating-based Sensor Design for Humidity Measurement in Chemically Harsh Environment

A temperature compensated Relative Humidity (RH) sensor incorporating Fibre Bragg Gratings (FBGs) has been developed to be tested in extremely harsh gaseous acidic environment. One FBG is coated with moisture sensitive polymer while the other was used for temperature compensation. The resonance wavelengths were chosen to be within suitable spectral bandwidths for efficient interpretation of both RH and temperature. The performance of the sensor was evaluated for use in challenging environment by trialing the sensors for over a month in a waste sewerage tank with highly acidic gaseous environment. The sensitivity of the sensor to RH/temperature is calculated to be 5 pm/%RH and 9 pm/̊C respectivel

Towards Mode-Multiplexed Fiber Sensors: An Investigation on the Spectral Response of Etched Graded Index OM4 Multi-Mode Fiber with Bragg grating for Refractive Index and Temperature Measurement

An investigation on the feasibility of utilizing Mode Division Multiplexing (MDM) for simultaneous measurement of Surrounding Refractive Index (SRI) and temperature using a single sensor element based on an etched OM4 Graded Index Multi Mode Fiber (GI-MMF) with an integrated fiber Bragg Grating (BG), is presented. The proposed work is focused on the concept of principle mode groups (PMGs) generated by the OM4 GI-MMF whose response to SRI and temperature would be different and thus discrimination of the said two parameters can be achieved simultaneously via a single sensor element. Results indicate that the response of all PMGs to temperature to be equal, i.e., 11.4 pm/°C, while the response to SRI depends on each PMG. Thus, it is evident that temperature “de-coupled” SRI measurement can be achieved by deducing the temperature effects experienced by the sensor element. Sensitivity of the PMGs to applied SRI varied from 3.04 nm/RIU to of 0.22 nm/RIU from the highest to lowest PMG, respectively. The results verify that it is feasible to obtain dual measurement of SRI and temperature simultaneously using the same, i.e., single, sensing element