Structure borne sound in motor-vehicles using statistical energy analysis

This Thesis is about the application of Statistical Energy Analysis (SEA) to the study of noise and vibration in motor vehicles. Methods for predicting the transmission of structural waves between body panels in motor cars are given. A complex joint technique based on the wave dynamic stiffness approach is discussed in detail. This technique can account for the complexities of the joint structures found in motor vehicles. Transmission of vibration energy between panels connected by a curved section of panel has been investigated using the complex joint modelling technique. Wave Intensity Analysis(WIA) and SEA were used to calculate the coupled panel vibration levels based on transmission coefficients calculated using the complex joint techniques. Energy Level Differences (ELDs) were measured for comparison with predicted results using laboratory models. SEA failed to accurately predict the ELDs except at low frequencies. However WIA was able to predicted the ELDs with reasonable accuracy using an existing expression for transmission at a panel corner joint. Two SEA models of a small passenger car have also been constructed. One assumes simpler joint configurations when calculating transmission coefficients and the other uses the complex joint technique. Panel ELDs were measured using a small passenger car. The SEA model using the complex joint method gives better agreement with measured ELDs than did the model using the simpler joints. saloon Sound Pressure Level (SPL) as a result of engine noise was measured. Both SEA models of the vehicle gave good agreement between measured and predicted Saloon SPL. A noise problem associated with exhaust misalignment is also investigated.Alexander Neilson Beques

Control strategies for integration of electric motor assist and functional electrical stimulation in paraplegic cycling: Utility for exercise testing and mobile cycling

AIM: The aim of this study was to investigate feedback control strategies for integration of electric motor assist and functional electrical stimulation (FES) for paraplegic cycling, with particular focus on development of a testbed for exercise testing in FES cycling, in which both cycling cadence and workrate are simultaneously well controlled and contemporary physiological measures of exercise performance derived. A second aim was to investigate the possible benefits of the approach for mobile, recreational cycling. METHODS: A recumbent tricycle with an auxiliary electric motor is used, which is adapted for paraplegic users, and instrumented for stimulation control. We propose a novel integrated control strategy which simultaneously provides feedback control of leg power output (via automatic adjustment of stimulation intensity) and cycling cadence (via electric motor control). Both loops are designed using system identification and analytical (model-based) feedback design methods. Ventilatory and pulmonary gas exchange response profiles are derived using a portable system for real-time breath-by-breath acquisition. RESULTS:We provide indicative results from one paraplegic subject in which a series of feedback-control tests illustrate accurate control of cycling cadence, leg power control, and external disturbance rejection. We also provide physiological response profiles from a submaximal exercise step test and a maximal incremental exercise test, as facilitated by the control strategy. CONCLUSION: The integrated control strategy is effective in facilitating exercise testing under conditions of well-controlled cadence and power output. Our control approach significantly extends the achievable workrate range and enhances exercise-test sensitivity for FES cycling, thus allowing a more stringent characterization of physiological response profiles and estimation of key parameters of aerobic function.We further conclude that the control approach can significantly improve the overall performance of mobile recreational cycling

NIR technologies for high speed fruit grading

Today’s consumers seek information about food products so they can purchase with confidence, even if it translates to higher priced items. It is the aim of this thesis to improve the instruments available for the prediction of food quality, in particular, to advance the technology used for the rapid, low cost, non-destructive analysis of the internal quality of fruit. This thesis contains both experimental and theoretical work covering two main areas of research: the first deals with issues related to the practical grading of fruit, the second with the NIR light penetration and distribution within a fruit. A ‘rotary grader’ has been built to enable the rapid, non-destructive assessment of fruit. Up to twenty fruit can be placed on a rotating disk, which can be spun at a controlled speed or moved to fixed positions for stationary studies. A variety of optical arrangements can be mounted to enable the acquisition of spectra from individual fruit in different ‘modes’ of operation. A comparison between the different optical arrangements is presented. It was found that transmission mode (where the light passes right through the fruit) performs better than reflectance mode (where the detected light comes primarily from near the surface of the fruit). This result has been previously predicted and has now been demonstrated with the equipment used in this work. Different angles of transmission are compared as well as different fruit orientations for their influence on fruit quality predictions. It was found that 90° transmission (where the light is detected at right angles to the illumination of the fruit) might work best for randomly orientated kiwifruit; if they are hand placed then 180° or 150° may be more effective. A study of mandarins suggested that the acid content cannot be assessed directly, but it can be inferred from surface properties such as colour and chlorophyll content. This is contrary to several published reports and questions the ability of NIR spectroscopy to measure low concentrations of acid in fruit. A third experiment showed that soluble solids content (SSC) and dry matter (DM) can be assessed from moving apples with a prediction error of 0.54 ± 0.07 °Brix (R²ₚ = 0.65) and 0.66 ± 0.08 % (R²ₚ = 0.80) respectively. A unique perspective is presented showing where the useful information is attained from the continuously moving fruit. Transmission and reflectance spectra from apples moving at speeds of up to 3 fruit/s have been recorded, and the optimal spectra from the sequence were combined for improved predictions. To investigate the NIR light distribution and penetration in fruit a fibre optic probe was built to take direct measurements of the light levels inside fruit. This enabled, for the first time, the degree of light penetration to be assessed without altering the optical boundaries of the fruit (for example cutting away sections of the fruit). Corresponding simulations using Monte Carlo photon tracing, match the experimental measurements. It was found that fruit such as mandarin exhibit strong internal reflection from the skin, a result that has not previously been reported. The influence of the core and other features in the fruit on the light penetration and distribution is also studied showing perturbations in the internal light levels mapping out these features

Understanding Somatic Mosaicism in Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 is caused by an unstable CTG repeat expansion in the 3' UTR of the DM1 protein kinase gene on chromosome 19. A neuromuscular disease with a broad spectrum of symptoms, DM1 also exhibits anticipation whereby disease severity increases through successive generations. Increasing measured allele size between patients correlates with an increased severity of symptoms and an earlier age of onset. However, this correlation is not precise and therefore measured allele length caimot be used as an accurate indicator of age of onset. This suggests that repeat length may not be the major determinant of disease severity. There is a high level of somatic mosaicism shown by the mutation and failure to take into account age-dependent somatic mosaicism in patients may have compromised the accuracy of clinical correlations. The aim of this project was to investigate simple approaches for correcting for age-dependent somatic mosaicism and also to develop computer software to allow us to simulate the progression of age-dependent somatic mosaicism. We have demonstrated that employing alternative approaches in both molecular diagnoses and statistical comparison can yield significantly improved repeat length / age of onset correlations. This conclusively shows that repeat length is by far the major determinant in DM1 disease onset. Simulation software was also successfully developed and preliminary results suggest that DM1 repeat instability is amenable to mathematical modelling in the future

Assessing the value of trees in sustainable grazing systems

The retention of trees in strips provides an option for managing non-remnant woody vegetation in native and sown pastures in northern Australia. However, the impact of tree strips on pasture production has not been previously researched in detail in southern Queensland. The influence of existing tree strips on pasture production in southern Queensland was measured at three grazing properties during 2004 and 2005. Soil and pasture attributes were sampled along transects 80 to 300 metres in length positioned perpendicular to tree strips. The tree strips ranged from 15 to 75 metres wide and were 120 to 500 metres apart. The effects of tree strips along the pasture transect were quantified in terms of pasture microclimate (e.g. temperature, humidity and, at one location, wind), pasture growth in grazed and exclosed situations, soil water, soil nutrients and condition, and nutrient availability. An experimental approach using exclosed pasture transects provided a useful ‘bioassay’ potentially integrating beneficial and competitive effects of tree strips on pasture growth as well as other factors (e.g. soil variability). Averaged across two locations and two years, the competitive effects of the tree strip were compensated to some extent by enhanced pasture growth at distances of 1-6 x tree height from the tree strip edge. However, the observed effects on pasture growth along the transect were likely to be due to different causes: pasture microclimate at one site, soil texture and microtopography at a second site and pasture establishment history at a third site. Thus, the trial highlighted the difficulty of attributing effects in real-world situations, given the number of possible causes including the tree strip effects on pasture microclimate and nutrient availability, soil surface disturbance, and systematic variation on soil and water redistribution due to soil micro-topography and felled timber. Despite these many sources of variation, general effects were derived from the field data consistent with other studies on tree strips and wind breaks across Australia. To extrapolate the project results to other locations, tree strip configurations and climates, a new version of the soil waterpasture growth simulation model GRASP was developed allowing simulation of tree and pasture effects and processes for various distances along a pasture transect perpendicular from the tree strip

Identifying the emergence of the superficial peroneal nerve through deep fascia on ultrasound and by dissection:Implications for regional anesthesia in foot and ankle surgery

Regional anesthesia relies on a sound understanding of anatomy and the utility of ultrasound in identifying relevant structures. We assessed the ability to identify the point at which the superficial peroneal nerve (SPN) emerges through the deep fascia by ultrasound on 26 volunteers (mean age 27.85 years ± 13.186; equal male: female). This point was identified, characterized in relation to surrounding bony landmarks (lateral malleolus and head of the fibula), and compared to data from 16 formalin‐fixed human cadavers (mean age 82.88 years ± 6.964; equal male: female). The SPN was identified bilaterally in all subjects. On ultrasound it was found to pierce the deep fascia of the leg at a point 0.31 (±0.066) of the way along a straight line from the lateral malleolus to the head of the fibula (LM‐HF line). This occurred on or anterior to the line in all cases. Dissection of cadavers found this point to be 0.30 (±0.062) along the LM‐HF line, with no statistically significant difference between the two groups (U = 764.000; exact two‐tailed P = 0.534). It was always on or anterior to the LM‐HF line, anterior by 0.74 cm (±0.624) on ultrasound and by 1.51 cm (±0.509) during dissection. This point was significantly further anterior to the LM‐HF line in cadavers (U = 257.700, exact two‐tailed P < 0.001). Dissection revealed the nerve to divide prior to emergence in 46.88% (n = 15) limbs, which was not identified on ultrasound (although not specifically assessed). Such information can guide clinicians when patient factors (e.g., obesity and peripheral edema) make ultrasound‐guided nerve localization more technically challenging.PostprintPeer reviewe

Fertiliser management effects on dissolved inorganic nitrogen in runoff from Australian sugarcane farms

Dissolved inorganic nitrogen (DIN) movement from Australian sugarcane farms is believed to be a major cause of crown-of-thorns starfish outbreaks which have reduced the Great Barrier Reef coral cover by ~21% (1985–2012). We develop a daily model of DIN concentration in runoff based on >200 field monitored runoff events. Runoff DIN concentrations were related to nitrogen fertiliser application rates and decreased after application with time and cumulative rainfall. Runoff after liquid fertiliser applications had higher initial DIN concentrations, though these concentrations diminished more rapidly in comparison to granular fertiliser applications. The model was validated using an independent field dataset and provided reasonable estimates of runoff DIN concentrations based on a number of modelling efficiency score results. The runoff DIN concentration model was combined with a water balance cropping model to investigate temporal aspects of sugarcane fertiliser management. Nitrogen fertiliser application in December (start of wet season) had the highest risk of DIN movement, and this was further exacerbated in years with a climate forecast for ‘wet’ seasonal conditions. The potential utility of a climate forecasting system to predict forthcoming wet months and hence DIN loss risk is demonstrated. Earlier fertiliser application or reducing fertiliser application rates in seasons with a wet climate forecast may markedly reduce runoff DIN loads; however, it is recommended that these findings be tested at a broader scale

Developing a Methodology Protocol for Identifying the Superficial Peroneal Nerve in Living Models Sonographically and Formalin-Fixed Cadavers Morphologically: a Proof of Concept Study

The superficial peroneal nerve (SPN) provides cutaneous innervation to the distal anterolateral leg and dorsum of foot.1 Knowing the position where the SPN penetrates the deep fascia, to become superficial, is useful in clinical practice (e.g. ankle blocks and internal fixation of distal fibular fractures). However, there is variability in the literature as to where the SPN penetrates the deep fascia as well as the methodology to identify it with no standardised guidelines. Our primary aim was to identify this point and create a methodology protocol that could be implemented in clinical practice. The study involved sonography of living healthy adult volunteers and dissection of formalin-fixed cadavers with no past history of pathology or surgery affecting the SPN. During sonography, the bony prominences of the fibular head and lateral malleolus were identified and marked with a straight line. A 6-12 MHz linear array ultrasound probe was positioned anterior to the lateral malleolus and moved proximally to identify the location where the SPN penetrates the deep fascia to lie in a superficial plane. The lateral malleolus-fibular head (length of fibula) and lateral malleolus-SPN distances were measured. The distance of emergence from the deep fascia of the SPN anterior or posterior to the length of fibula was measured (fig 1). In the cadavers, a skin incision was made from the tibial tuberosity to the anterior intermalleolar line and the skin reflected laterally to a line posterior to fibula. The superficial fascia was explored to identify the SPN and branches (fig 2). The same bony landmarks/measurements as in the sonography were marked and measured to allow for comparison with the sonographic methodology. We successfully developed a protocol that can provide standardisation for identifying the SPN. This can reduce incorrect identification and improve success rates of clinical procedures, though individual variation must be considered. Reference: 1. STANDRING, S (Editor) 2008. Gray’s Anatomy The Anatomical Basis of Clinical Practice (Fortieth Edition). London: Churchill Livingstone ELSEVIER, page 1427. Acknowledgements: For their help and support in this study, we would to thank the volunteers, the anatomy technical staff, and the clinical skills suite manager from the University of St Andrews Medical School

Developing a Methodology Protocol for Identifying the Superficial Peroneal Nerve in Living Models Sonographically and Formalin-Fixed Cadavers Morphologically: a Proof of Concept Study

The superficial peroneal nerve (SPN) provides cutaneous innervation to the distal anterolateral leg and dorsum of foot.1 Knowing the position where the SPN penetrates the deep fascia, to become superficial, is useful in clinical practice (e.g. ankle blocks and internal fixation of distal fibular fractures). However, there is variability in the literature as to where the SPN penetrates the deep fascia as well as the methodology to identify it with no standardised guidelines. Our primary aim was to identify this point and create a methodology protocol that could be implemented in clinical practice. The study involved sonography of living healthy adult volunteers and dissection of formalin-fixed cadavers with no past history of pathology or surgery affecting the SPN. During sonography, the bony prominences of the fibular head and lateral malleolus were identified and marked with a straight line. A 6-12 MHz linear array ultrasound probe was positioned anterior to the lateral malleolus and moved proximally to identify the location where the SPN penetrates the deep fascia to lie in a superficial plane. The lateral malleolus-fibular head (length of fibula) and lateral malleolus-SPN distances were measured. The distance of emergence from the deep fascia of the SPN anterior or posterior to the length of fibula was measured (fig 1). In the cadavers, a skin incision was made from the tibial tuberosity to the anterior intermalleolar line and the skin reflected laterally to a line posterior to fibula. The superficial fascia was explored to identify the SPN and branches (fig 2). The same bony landmarks/measurements as in the sonography were marked and measured to allow for comparison with the sonographic methodology. We successfully developed a protocol that can provide standardisation for identifying the SPN. This can reduce incorrect identification and improve success rates of clinical procedures, though individual variation must be considered. Reference: 1. STANDRING, S (Editor) 2008. Gray’s Anatomy The Anatomical Basis of Clinical Practice (Fortieth Edition). London: Churchill Livingstone ELSEVIER, page 1427. Acknowledgements: For their help and support in this study, we would to thank the volunteers, the anatomy technical staff, and the clinical skills suite manager from the University of St Andrews Medical School