Architectures for vibration-driven micropower generators

Published versio

Scaling Laws for Energy Harvesters in a Marine Environment

Published versio

Acoustic flow sensor using a passive bell transducer

Sensing based on a passive transducer that is wirelessly linked to a nearby data collection node can offer an attractive solution for use in remote, inaccessible, or harsh environments. Here we report a pipe flow sensor based on this principle. A transducer mounted inside the pipe generates an acoustic signal that is picked up by an external microphone. The passive transducer comprises a cavity with a trapped ball that can oscillate in response to flow. Its collisions generate an acoustic signal correlated to the flow speed. The transducer is implemented on a 6 mm diameter probe and characterized as a water flow meter. The time - average microphone voltage output is calculated by an analogue circuit, without any further signal processing. With the microphone mounted on the probe, and for flow rates in the range 0.35 m/s to 6.5 m/s, correlation between the sensor voltage output and flow rate data from a commercial flow meter is demonstrated with a worst-case accuracy of 2%. This was achieved by simple averaging of the acoustic pulse train over a 5-second time interval. Consistent correlation with the microphone mounted on the pipe wall at distances up to 150 mm from the probe location is also reported. These results demonstrate the viability of remote acoustic flow sensing using passive structures and offer a simple and minimally invasive flow monitoring method

Energy harvesting from human and machine motion for wireless electronic devices

Published versio

Micro-machined variable capacitors for power generation

Accepted versio

Evaluation of the Clore Art Studio

Three core questions The three core questions that the Family Learning team at Manchester Art Gallery would like this evaluation to address are: 1. What learning takes place in the Clore Art Studio and how can we optimise this learning environment in the future? 2. Which audience or age group benefit the most from this space and how can we talk about their experiences? 3. What is the role of the artist and the volunteer in facilitating the space? In order to address each of these questions members of the Manchester Metropolitan University evaluation team gathered qualitative data that included observations including filmed documentation of children, families, young adults, teachers, members of the Family Learning Team and volunteers when engaged with/in the Clore Art Studio Space. Additionally interviews were undertaken with the Family Learning Manager, volunteers, parents, teachers, the artists that helped to design the Studio space and the artists that facilitated the space across the weekends. The evaluation team also had access to reflective diaries that were regularly completed by the volunteers and the Gallery’s own archives of film and photographs

Potential use of oxygen as a metabolic biosensor in combination with T2*-weighted MRI to define the ischemic penumbra

We describe a novel magnetic resonance imaging technique for detecting metabolism indirectly through changes in oxyhemoglobin:deoxyhemoglobin ratios and T2* signal change during ‘oxygen challenge’ (OC, 5 mins 100% O2). During OC, T2* increase reflects O2 binding to deoxyhemoglobin, which is formed when metabolizing tissues take up oxygen. Here OC has been applied to identify tissue metabolism within the ischemic brain. Permanent middle cerebral artery occlusion was induced in rats. In series 1 scanning (n=5), diffusion-weighted imaging (DWI) was performed, followed by echo-planar T2* acquired during OC and perfusion-weighted imaging (PWI, arterial spin labeling). Oxygen challenge induced a T2* signal increase of 1.8%, 3.7%, and 0.24% in the contralateral cortex, ipsilateral cortex within the PWI/DWI mismatch zone, and ischemic core, respectively. T2* and apparent diffusion coefficient (ADC) map coregistration revealed that the T2* signal increase extended into the ADC lesion (3.4%). In series 2 (n=5), FLASH T2* and ADC maps coregistered with histology revealed a T2* signal increase of 4.9% in the histologically defined border zone (55% normal neuronal morphology, located within the ADC lesion boundary) compared with a 0.7% increase in the cortical ischemic core (92% neuronal ischemic cell change, core ADC lesion). Oxygen challenge has potential clinical utility and, by distinguishing metabolically active and inactive tissues within hypoperfused regions, could provide a more precise assessment of penumbra

Miniaturized wet-wet differential pressure sensor

We report a miniaturized wet-wet differential pressure sensor with applications in pressure and flow sensing in water networks and other harsh environments. The device is similar in concept to a conventional wet-wet differential pressure sensor in that the sensing element is protected from the external environment by oil-filled cavities closed off by corrugated diaphragms. However, with a package envelope of 11.0 x 4.8 x 3.4 mm 3 , corresponding to a volume of only 0.18 cm 3 , the device is considerably smaller than commercially available wet-wet differential pressure sensors. A high degree of miniaturization has been achieved by using micromachining to fabricate the corrugated diaphragms. Preliminary experimental results are presented showing operation of the device as a delta-pressure flow speed sensor in a water flow test rig

On relating rheology and oral tribology to sensory properties in hydrogels

The aim of this study was to understand the relationship between rheological, tribological and sensory properties (n = 11 panellists) of hydrogels differing in hydrocolloid type, concentration and degree of inhomogeneity. Fracture properties of hydrogels containing different ratios of κ-carrageenan (κC) and/or locust bean gum (LBG), sodium alginate (NaA), 300/1000 μm calcium alginate beads (CaA) at 1–4 wt% concentration were determined. Viscosity and friction coefficients (μ) of the hydrogel-boli after simulated oral processing were characterized. Tribology measurements were conducted in a polydimethylsiloxane ball/disc set-up with pre-adsorbed artificial salivary film at 37 °C. ’Scaling’ with boli viscosity showed good agreement of observed data with the Stribeck master curve, however only in the mixed regime i.e. at intermediate values of the product of velocity and lubricant viscosity (Uη). Low μ values of gel boli in the boundary regime were largely driven by the formation of a viscous layer of bolus fragments between opposing surfaces. Fracture properties of hydrogels and boli viscosity were correlated with all chewing-related texture attributes i.e. ‘firm’, ‘elastic’, ‘chewy’ and ‘cohesive’ and inversely correlated with lubrication-related attributes ‘melting’ and ‘pasty’ (p<0.05). On the other hand, μ of the bolus filtrate at orally relevant speeds (50 mm/s) was inversely correlated with lubrication-related attributes ‘pasty’ and positively with ‘slippery’ (p<0.05). The lack of correlations with ‘smooth’ could be explained due to sample inhomogeneity and the absence of ‘ball-bearing’-ability of the gel beads. A combination of initial fracture properties, boli viscosity and tribology of bolus filtrates (mixed regime) impacted the lubrication-related attribute ‘salivating’ (p<0.05)