The Evolution of Nova V382 Vel 1999

We report results of spectroscopic observations of V382 Vel (Nova Vel 1999) carried out at La Silla between 5 and 498 days after maximum light (23 May 1999, V(max) $\sim 2.3\pm 0.1$). The analysis of the photometric and spectroscopic evolution shows this object to be a {\sl fast nova} belonging to the Fe II {\sl broad} spectroscopic class. A distance of 1.7 kpc ($\pm 20$) is derived from the maximum magnitude vs. rate of decline relationship after correcting for the small reddening toward the nova, E(B--V)\lsim 0.10. From the measured H$\alpha$ flux and the associated rate of expansion we derive an approximate mass for the ejected shell, M_{env}\lsim 10^{-5} M$_\odot$. We have also observed during the early decline a broad, short-lived (\lsim 10 days) feature at 6705-6715 \AA for which several identifications are possible, one of which is the lithium doublet at 6708 \AA and which could place an empirical limit on the lithium production that might occur during the outburst of a {\sl fast nova}. The high luminosity at maximum, M$_v=-8.9$, and the relatively small height above the galactic plane (z\lsim 160pc) suggest that V382 Vel originated from a massive white dwarf, likely in the mass range 1.1--1.2 M$_\odot$.Comment: 13 pages + 9 plots(gif). Accepted by A&

The tetanic depression in fast motor units of mammalian skeletal muscle can be evoked by lengthening of one initial interpulse interval

A lower than expected tetanic force (the tetanic depression) is regularly observed in fast motor units (MUs) when a higher stimulation frequency immediately follows a lower one. The aim of the present study was to determine whether prolongation of only the first interpulse interval (IPI) resulted in tetanic depression. The experiments were carried out on fast MUs of the medial gastrocnemius muscle in cats and rats. The tetanic depression was measured in each case as the force decrease of a tetanus with one IPI prolonged in relation to the tetanic force at the respective constant stimulation frequency. Force depression was observed in all cases studied and was considerably greater in cats. For cats, the mean values of force depression amounted to 28.64% for FR and 10.86% for FF MUs whereas for rats 9.30 and 7.21% for FR and FF motor units, respectively. Since the phenomenon of tetanic depression in mammalian muscle is commonly observed even after a change in only the initial interpulse interval within a stimulation pattern, it can effectively influence processes of force regulation during voluntary activity of a muscle, when motoneurones progressively increase the firing rate

A Review of Non-Invasive Techniques to Detect and Predict Localised Muscle Fatigue

Muscle fatigue is an established area of research and various types of muscle fatigue have been investigated in order to fully understand the condition. This paper gives an overview of the various non-invasive techniques available for use in automated fatigue detection, such as mechanomyography, electromyography, near-infrared spectroscopy and ultrasound for both isometric and non-isometric contractions. Various signal analysis methods are compared by illustrating their applicability in real-time settings. This paper will be of interest to researchers who wish to select the most appropriate methodology for research on muscle fatigue detection or prediction, or for the development of devices that can be used in, e.g., sports scenarios to improve performance or prevent injury. To date, research on localised muscle fatigue focuses mainly on the clinical side. There is very little research carried out on the implementation of detecting/predicting fatigue using an autonomous system, although recent research on automating the process of localised muscle fatigue detection/prediction shows promising results

The impact of biodiesel and alternative diesel fuel components on filter blocking through accelerated testing on a novel high pressure common rail non-firing rig

Increases in FAME content in diesel have coincided with advances in high pressure injector system technology. Previously, the unsaturation present in FAME has generally been thought to result in on-vehicle fuel degradation leading to solid formation. However, a growing number of vehicle breakdowns have implicated the increasing temperatures and pressures experienced by the fuel in the new injector system technologies. The majority of studies into diesel degradation are conducted under non-representative laboratory conditions, or extrapolated from the deposits found in filters from vehicles. In this study the cause of this degradation was investigated by using a novel High Pressure Common Rail (HPCR) non-firing rig, simulating realistic, albeit accelerated, conditions. The deposition on the system fuel filter was monitored, for B0, B10 and surrogate diesel components. Degradation was found to occur in the absence of FAME with both B10 and B0 fuels showing a similar rate of deposition. A study of synthetic surrogates demonstrated that, rather than FAME, any trace fuel component, under sufficiently high pressures and temperatures in the HPCR is prone to degradation. This suggests that rather than FAME being the sole factor in the increasing instability of diesel fuels, it is actually the increase in temperatures and pressures that the fuel is subjected to. This also demonstrates that while a large body of work on the oxidative instability of biodiesel in the chemical laboratory is indicative of instability, this does not mimic what is seen under more realistic vehicle conditions and the focus on FAME stability is misleading.</p