An experimental and finite element study of the low-cycle fatigue failure of a galvanised steel lighting column

This paper presents the results of a low-cycle fatigue test on a lighting column. The wind induced vibration phenomena responsible for low cycle fatigue in such structures is discussed and the failure mechanism is examined. It was initially thought that poor quality weld detail was the major influence on the fatigue life of such columns. However, the significant role of the galvanised coating in the failure process is also highlighted. The experimental results are compared with those from a detailed 3D finite element model. Various methods of calculating hot-spot stresses at welded joints are examined and use of a simple peak stress removal approach is shown to produce significantly different values compared with the other methods examined

SPIRAL Phase A: A Prototype Integral Field Spectrograph for the AAT

We present details of a prototype fiber feed for use on the Anglo-Australian Telescope (AAT) that uses a dedicated fiber-fed medium/high resolution (R > 10000) visible-band spectrograph to give integral field spectroscopy (IFS) of an extended object. A focal reducer couples light from the telescope to the close-packed lenslet array and fiber feed, allowing the spectrograph be used on other telescopes with the change of a single lens. By considering the properties of the fibers in the design of the spectrograph, an efficient design can be realised, and we present the first scientific results of a prototype spectrograph using a fiber feed with 37 spatial elements, namely the detection of Lithium confirming a brown dwarf candidate and IFS of the supernova remnant SN1987A.Comment: 41 pages, 15 figures, 3 tables; accepted by PAS

Dose–response effect of a whey protein preload on within-day energy intake in lean subjects

The effect of consuming different amounts of whey protein on appetite and energy intake was investigated in two separate studies using randomised, crossover designs. Healthy-weight men and women (range: BMI 19·0–25·0 kg/m2, age 19·4–40·4 years) consumed one of four 400 ml liquid preloads, followed by an ad libitum test meal 90 min later. In study 1, preloads were 1675 kJ with 12·5, 25 or 50 % of energy from protein, and in study 2, preloads were 1047 kJ with 10, 20 or 40 % energy from protein. Flavoured water was used as the control in both the studies. Appetite ratings were collected immediately before 30, 60 and 90 min after consuming the preloads; and immediately, 30 and 60 min after consuming the test meal. In study 1, energy intake following the control preload (4136 (sem 337) kJ) was significantly higher than each of the 12·5 % (3520 (sem 296) kJ), 25 % (3384 (sem 265) kJ) and 50 % (2853 (sem 244) kJ) protein preloads (P < 0·05). Intake after the 12·5 % preload was significantly higher than following 25 and 50 % preloads (P < 0·05). In study 2, energy intake following the control preload (4801 (sem 325) kJ) was higher than following the 10 % (4205 (sem 310) kJ), 20 % (3988 (sem 250) kJ) and 40 % (3801 (sem 245) kJ) protein preloads (P < 0·05). There were no differences in subjective appetite ratings between preloads in either study. These findings indicate a dose–response effect of protein content of the preload on energy intake at a subsequent meal

Large-Scale Fermentation of E. Coli for the Production of High-Purity Isoprene

We present a process for the production of isoprene via the fermentation of glucose. Based on our current specifications, we conclude that the use of recombinant E.coli for the fermentation of glucose is a novel yet unprofitable venture. Our current design entails the continuous production of isoprene using 3 pre-seed, 3 seed, and 5 production fermenters each with a production fermentation time of 72 hours. Our scheduling of the fermenters allowed us to produce isoprene continuously at a steady rate, and the liquid by-products of the fermentation were removed and sterilized at the end of each batch. Isoprene was mainly present in the vapor phase during the fermentation and was purified using a combination of an absorption using ISOPAR v, stripping with steam, and separation using a flash vessel. It was desired that the fermentation was operated near the minimum oxygen concentration (MOC) as such conditions allowed for the highest production rate of isoprene based on the preliminary studies done by Chotani in their patent. The fermentation was operated at 34 °C and 1.7 bar with glucose and oxygen as the reactants producing isoprene, carbon dioxide, and water as the products. The results of our design suggest that the price of isoprene is too low when compared to the costs of raw materials, making this process economically unfeasible under present market conditions. We project that $4.08 worth of glucose will be need for each pound of isoprene which currently goes for$0.79/lb. Additionally, the metabolic pathway of isoprene is highly exothermic, requiring large utility requirements in terms of chilled water to remove heat from the fermenters. We are unsure of impacts of rapidly changing the temperature of E.Coli on production as there is no data regarding the robustness of the strain. Overall, the fixed capitals costs incurred make this process even more unappealing for further consideration

Phasing of muscle gene expression with fasting-induced recovery growth in Atlantic salmon

Background: Many fish species experience long periods of fasting in nature often associated with seasonal reductions in water temperature and prey availability or spawning migrations. During periods of nutrient restriction, changes in metabolism occur to provide cellular energy via catabolic processes. Muscle is particularly affected by prolonged fasting as myofibrillar proteins act as a major energy source. To investigate the mechanisms of metabolic reorganisation with fasting and refeeding in a saltwater stage of Atlantic salmon (Salmo salar L.) we analysed the expression of genes involved in myogenesis, growth signalling, lipid biosynthesis and myofibrillar protein degradation and synthesis pathways using qPCR. Results: Hierarchical clustering of gene expression data revealed three clusters. The first cluster comprised genes involved in lipid metabolism and triacylglycerol synthesis (ALDOB, DGAT1 and LPL) which had peak expression 3-14d after refeeding. The second cluster comprised ADIPOQ, MLC2, IGF-I and TALDO1, with peak expression 14-32d after refeeding. Cluster III contained genes strongly down regulated as an initial response to feeding and included the ubiquitin ligases MuRF1 and MAFbx, myogenic regulatory factors and some metabolic genes. Conclusion: Early responses to refeeding in fasted salmon included the synthesis of triacylglycerols and activation of the adipogenic differentiation program. Inhibition of MuRF1 and MAFbx respectively may result in decreased degradation and concomitant increased production of myofibrillar proteins. Both of these processes preceded any increase in expression of myogenic regulatory factors and IGF-I. These responses could be a necessary strategy for an animal adapted to long periods of food deprivation whereby energy reserves are replenished prior to the resumption of myogenesis.Publisher PDFPeer reviewe

On the survivability and detectability of terrestrial meteorites on the moon

Materials blasted into space from the surface of early Earth may preserve a unique record of our planet's early surface environment. Armstrong et al. (2002) pointed out that such materials, in the form of terrestrial meteorites, may exist on the Moon and be of considerable astrobiological interest if biomarkers from early Earth are preserved within them. Here, we report results obtained via the AUTODYN hydrocode to calculate the peak pressures within terrestrial meteorites on the lunar surface to assess their likelihood of surviving the impact. Our results confirm the order-of-magnitude estimates of Armstrong et al. (2002) that substantial survivability is to be expected, especially in the case of relatively low velocity (ca. 2.5 km/s) or oblique (≤45°) impacts, or both. We outline possible mechanisms for locating such materials on the Moon and conclude that searching for them would be a scientifically valuable activity for future lunar exploration

A brief report on the development of a theoretically-grounded intervention to promote patient autonomy and self-management of physiotherapy patients: Face validity and feasibility of implementation

Background Clinical practice guidelines for the treatment of low back pain suggest the inclusion of a biopsychosocial approach in which patient self-management is prioritized. While many physiotherapists recognise the importance of evidence-based practice, there is an evidence practice gap that may in part be due to the fact that promoting self-management necessitates change in clinical behaviours. Evidence suggests that a patient’s motivation and maintenance of self-management behaviours can be positively influenced by the clinician’s use of an autonomy supportive communication style. Therefore, the aim of this study was to develop and pilot-test the feasibility of a theoretically derived implementation intervention to support physiotherapists in using an evidence-based autonomy supportive communication style in practice for promoting patient self-management in clinical practice. Methods A systematic process was used to develop the intervention and pilot-test its feasibility in primary care physiotherapy. The development steps included focus groups to identify barriers and enablers for implementation, the theoretical domains framework to classify determinants of change, a behaviour change technique taxonomy to select appropriate intervention components, and forming a testable theoretical model. Face validity and acceptability of the intervention was pilot-tested with two physiotherapists and monitoring their communication with patients over a three-month timeframe. Results Using the process described above, eight barriers and enablers for implementation were identified. To address these barriers and enablers, a number of intervention components were selected ranging from behaviour change techniques such as, goal-setting, self-monitoring and feedback to appropriate modes of intervention delivery (i.e. continued education meetings and audit and feedback focused coaching). Initial pilot-testing revealed the acceptability of the intervention to recipients and highlighted key areas for refinement prior to scaling up for a definitive trial. Conclusion The development process utilised in this study ensured the intervention was theory-informed and evidence-based, with recipients signalling its relevance and benefit to their clinical practice. Future research should consider additional intervention strategies to address barriers of social support and those beyond the clinician level

Effective Temperatures of a Driven System Near Jamming

Fluctuations in a model of a sheared, zero-temperature foam are studied numerically. Five different quantities that reduce to the true temperature in an equilibrium thermal system are calculated. All five have the same shear-rate dependence, and three have the same value. Near the onset of jamming, the relaxation time is the same function of these three temperatures in the sheared system as of the true temperature in an unsheared system. These results imply that statistical mechanics is useful for the system and provide strong support for the concept of jamming.Comment: 4 pages, 4 postscript figure

El Niño and the delayed action oscillator

We study the dynamics of the El Niño phenomenon using the mathematical model of delayedaction oscillator (DAO). Topics such as the influence of the annual cycle, global warming, stochastic influences due to weather conditions and even off-equatorial heat-sinks can all be discussed using only modest analytical and numerical resources. Thus the DAO allows for a pedagogical introduction to the science of El Niño and La Niña while at the same time avoiding the need for large-scale computing resources normally associated with much more sophisticated coupled atmosphere-ocean general circulation models. It is an approach which is ideally suited for student projects both at high school and undergraduate level