The aim of this study was to develop a new type of preoperative flexibility test for adolescent idiopathic scoliosis. The objective was to develop a test that was standardized and allow for the measurement of in-vivo forces required for curve correction. It was undertaken to compare the results of this new test with side-bending radiographs. Various preoperative radiographic techniques have been used to assess flexibility in patients awaiting scoliosis correction surgery. The major limitation of these investigations is a lack of standardization. The side-bending radiograph is the current gold standard, against which this new test was compared. A prospective clinical study was conducted. An axial traction force of 1.5 times body weight was applied through the spine of patients using a traction jig. Posteroanterior, side-bending and traction radiographs were taken. Cobb angle and apical vertebra axial rotation measurements were obtained. Flexibility indices in the coronal and axial planes were calculated. Cobb angle reduction and axial derotation were compared between the two methods. A total of 15 (12 female and three male) patients, with a mean age of 15.1 years, were assessed. The mean force imparted on traction films was 800 N. The major curve Cobb angle measurements were 60.4° on standing posteroanterior radiograph, 52.7° on side-bend film and 44.5° on traction at 1.5 times body weight. The corresponding apical vertebrae axial rotations were 23.9°, 22.2° and 16.5°, respectively. The mean Cobb angle reduction was 15.9 for traction and 7.7 for side-bend radiographs (P<0.0001). The mean apical vertebra derotation was 7.4 for traction and 1.7° for side-bend radiographs (P=0.0083). The mean flexibility index in the coronal plane was 0.479. The mean flexibility index in the axial plane was 0.240. Our novel method of traction radiographs at 1.5 times body weight is a safe and reproducible method of assessing curve flexibility in patients with scoliosis. This method achieves a larger Cobb angle and axial derotation when compared with side-bending radiographs.

Electrical energy storage will play a key role in the transition to a low carbon energy network. Liquid air energy storage (LAES) is a thermal–mechanical energy storage technology that converts electricity to thermal energy. This energy is stored in three ways: as latent heat in a tank of liquid air, as warm sensible heat in a hot tank and as cold sensible heat in a packed bed regenerator (PBR), which is the focus of this paper. A PBR was selected because the temperature range (−196 °C to 10 °C) prohibits storage in liquid media, as most fluids will undergo a phase change over a near 200 °C temperature range. A change of phase in the storage media would result in exergy destruction and loss of efficiency of the LAES device. Gravel was selected as the storage media, as (a) many gravels are compatible with cryogenic temperatures and (b) the low cost of the material if it can be used with minimal pre-treatment. PBRs have been extensively studied and modelled such as the work by Schumann, described by Wilmott and later by White. However, these models have not been applied to and validated for a low temperature store using gravel. In the present research, a comprehensive modelling and experimental program was undertaken to produce a validated model of a low-temperature PBR. This included a study of the low-temperature properties of various candidate gravels, implementation of a modified Schumann model and validation using a laboratory scale packed bed regenerator. Two sizes of gravel at a range of flow rates were tested. Good agreement between the predicted and measured temperature fields in the PBR was achieved when a correlation factor was applied to account for short circuiting of the storage media through flow around the interface between the walls of the regenerator and storage media.

This paper presents experimental work on the heat transfer characteristics of a dilute impinging air-water mist jet. Time-averaged heat transfer measurements are reported, as well as simultaneously obtained high-speed shadowgraph imaging flow visualisation and heat transfer measurements; images of the mist jet impingement and the liquid film that forms on the impingement surface are also included. It is determined that the surface liquid morphology varies with mist loading fraction, and that the heat transfer behaviour of the mist jet reflects these changes. Intermittent thermal disturbance caused by the impingement of the mist jet droplets is proposed as the dominant heat transfer mechanism when the mist loading fraction is very low; as the mist loading fraction increases, evaporation from the surface liquid film and convective cooling due to the film flow become more significant.

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