Application of short air curtains in retail display refrigerators

In Europe, Ecodesign and Energy Labelling regulations for refrigerated retail display cabinets will come into force in January 2017 and manufacturers are seeking new technologies to maximise the efficiency of their products. Conventional multi deck cabinets have a single column of cold air from the top to the bottom of the merchandising envelope. The colder, denser air causes a stack effect and pressure builds at the base of air curtain causing cold air spillage from the cabinet and compromising temperature stability and energy efficiency. By contrast, with short air curtains the merchandising envelope can be divided into separate cells between shelves. The smaller cells have a shorter air column and independent management of air movement. The net result is a substantial reduction in cold air spillage from the case and improved temperature stability. This paper presents a technical and performance comparison between short air curtain technology and conventional cabinets

New apparatus to provide repeatable surface temperature-time treatments on inoculated food samples

The final stage of the BUGDEATH project (James and Evans, 2005) was to further develop the surface heating and cooling apparatus so it would be suitable for commercial exploitation. The new apparatus can be accommodated on a bench top and produces faster more uniform heating and cooling cycles than that previously described. It can heat the surface of a food from 8 to 120 °C in 14 s, cool from 120 to 40 °C in 28 s and then to 8 °C in 5 min. There is an average control error of approximately ±1 °C and a temperature variation over the surface of the sample of only 1.2 °C. Wet heating, using steam at 100 °C, was achieved using a portable steam generator. The price of the parts which made up the apparatus were approximately €10 000 and it takes approximately two person-weeks to build. © 2005 Elsevier Ltd. All rights reserved

Three-dimensional effects of an air curtain used to restrict cold room infiltration

The aim of this study was to compare the measured effectiveness of an air curtain device at different jet velocities against a three-dimensional (3-D) computational fluid dynamics (CFD) model. The air curtain device was not as wide as the entrance and had a geometry that encouraged 3-D flow. By carefully setting up the air curtain an effectiveness of 0.71 was achieved compared to the initial value of only 0.31 as set by the air curtain device installer. The 3-D CFD model predicted the infiltration through the entrance with no air curtain to an accuracy of within 20-32%. The predicted effectiveness, E, of the air curtain at different jet velocities was 0.10-0.15 lower than measured. The shape of the effectiveness curve against jet velocity was well predicted. CFD has shown that the flow from this air curtain cannot be considered as 2-D. The central part of the jet is deflected away from the cold store by the Coanda effect caused by the air curtain device's fan body. The edges of the jet are deflected into the cold store by the stack pressures and turn into the void caused by the deflected central jet. © 2006 Elsevier Inc. All rights reserved

Design and development of apparatus to provide repeatable surface temperature-time treatments on inoculated food samples

The majority of data relating heat treatments to thermal death kinetics has previously been obtained by carrying out in vitro tests on small samples of microorganisms in growth medium or food slurries. However, strong evidence exists that suggests microbial death on heat-treated food surfaces cannot be predicted accurately from such systems. An apparatus was therefore designed to enable microbial death on food surfaces to be quantified. The apparatus uses hot air to provide a ‘dry’ heat treatment to raise the surface of a food sample to a given temperature, up to 100 °C, hold and then cool it. The surface temperature was measured using an infra-red (IR) thermometer and the air heater was controlled to give a specified surface temperature history. Steam was also used to provide a ‘wet’, but less controlled heating cycle

Personalised profiling to identify clinically relevant changes in tremor due to multiple sclerosis

Background: There is growing interest in sensor-based assessment of upper limb tremor in multiple sclerosis and other movement disorders. However, previously such assessments have not been found to offer any improvement over conventional clinical observation in identifying clinically relevant changes in an individual's tremor symptoms, due to poor test-retest repeatability. Method: We hypothesised that this barrier could be overcome by constructing a tremor change metric that is customised to each individual's tremor characteristics, such that random variability can be distinguished from clinically relevant changes in symptoms. In a cohort of 24 people with tremor due to multiple sclerosis, the newly proposed metrics were compared against conventional clinical and sensor-based metrics. Each metric was evaluated based on Spearman rank correlation with two reference metrics extracted from the Fahn-Tolosa-Marin Tremor Rating Scale: a task-based measure of functional disability (FTMTRS B) and the subject's self-assessment of the impact of tremor on their activities of daily living (FTMTRS C). Results: Unlike the conventional sensor-based and clinical metrics, the newly proposed ’change in scale’ metrics presented statistically significant correlations with changes in self-assessed impact of tremor (max R2>0.5,p< 0.05 after correction for false discovery rate control). They also outperformed all other metrics in terms of correlations with changes in task-based functional performance (R2=0.25 vs. R2=0.15 for conventional clinical observation, both p< 0.05).Conclusions: The proposed metrics achieve an elusive goal of sensor-based tremor assessment: improving on conventional visual observation in terms of sensitivity to change. Further refinement and evaluation of the proposed techniques is required, but our core findings imply that the main barrier to translational impact for this application can be overcome. Sensor-based tremor assessments may improve personalised treatment selection and the efficiency of clinical trials for new treatments by enabling greater standardisation and sensitivity to clinically relevant changes in symptoms