Strong interaction of a turbulent spot with a shock-induced separation bubble

Direct numerical simulations have been conducted to study the passage of a turbulent spot through a shock-induced separation bubble. Localized blowing is used to trip the boundary layer well upstream of the shock impingement, leading to mature turbulent spots at impingement, with a length comparable to the length of the separation zone. Interactions are simulated at free stream Mach numbers of two and four, for isothermal (hot) wall boundary conditions. The core of the spot is seen to tunnel through the separation bubble, leading to a transient reattachment of the flow. Recovery times are long due to the influence of the calmed region behind the spot. The propagation speed of the trailing interface of the spot decreases during the interaction and a substantial increase in the lateral spreading of the spot was observed. A conceptual model based on the growth of the lateral shear layer near the wingtips of the spot is used to explain the change in lateral growth rat

Risk factors associated with lambing traits

peer-reviewedThis article was first published in Animal (2016), 10:1, pp 89–95, © The Animal Consortium 2015The objective of this study was to establish the risk factors associated with both lambing difficulty and lamb mortality in the Irish sheep multibreed population. A total of 135 470 lambing events from 42 675 ewes in 839 Irish crossbred and purebred flocks were available. Risk factors associated with producer-scored ewe lambing difficulty score (scale of one (no difficulty) to four (severe difficulty)) were determined using linear mixed models. Risk factors associated with the logit of the probability of lamb mortality at birth (i.e. binary trait) were determined using generalised estimating equations. For each dependent variable, a series of simple regression models were developed as well as a multiple regression model. In the simple regression models, greater lambing difficulty was associated with quadruplet bearing, younger ewes, of terminal breed origin, lambing in February; for example, first parity ewes experienced greater (P7.0 kg) birth weights, quadruplet born lambs and lambs that experienced a more difficult lambing (predicted probability of death for lambs that required severe and veterinary assistance of 0.15 and 0.32, respectively); lambs from dual-purpose breeds and born to younger ewes were also at greater risk of mortality. In the multiple regression model, the association between ewe parity, age at first lambing, year of lambing and lamb mortality no longer persisted. The trend in solutions of the levels of each fixed effect that remained associated with lamb mortality in the multiple regression model, did not differ from the trends observed in the simple regression models although the differential in relative risk between the different lambing difficulty scores was greater in the multiple regression model. Results from this study show that many common flock- and animal-level factors are associated with both lambing difficulty and lamb mortality and management of different risk category groups (e.g. scanned litter sizes, ewe age groups) can be used to appropriately manage the flock at lambing to reduce their incidence

A test facility for hypervelocity rarefied flows

This paper describes a rarefied hypervelocity test facility producing gas speeds greater than 7 km/s. The X1 expansion tube at the University of Queensland has been used to produce nitrogen flows at 8.9 and 9.5 km/s with test flow durations of 50 and 40 microsecond­s respectively. Rarefied flow is indicated by values of the freestream breakdown parameter > 0.1 (Cheng's rarefaction parameter < 10) and freestream Knudsen numbers up to 0.038, based on a model size of 9 mm. To achieve this, the test gas is expanded from the end of the acceleration tube into a dump tank. Nominal conditions in the expansion are derived from CFD predictions. Measured bar gauge (Pitot) pressures show that the flow is radially uniform when the Pitot pressure has decreased by a factor ten. The measured bar gauge pressures are an increasing fraction of the expected Pitot pressure as the rarefaction parameters increase

Climate change and the rental sector: Mapping the legislative and policy context: Analysis

The Briefing Paper series of the ‘Rental housing, climate change and adaptive capacity: a case study of Newcastle NSW’ project seeks to provide readers with access to current research on rental sector adaptation to climate change. Briefing Papers produced by the project team are working documents that provide a forum on theoretical, methodological and practical issues related to climate change adaption in rental housing. The project is funded by the National Climate change Adaptation Facility (NCCARF) for 2012. The publication as a ‘Briefing Paper’ does not preclude subsequent publication in scholarly journals, books or reports. Unless otherwise stated, ‘Rental housing, climate change and adaptive capacity’ publications are presented as contributions to debate and discussion and represent our developing thinking about the research. We are hoping that they may facilitate feedback from readers, researchers, renters and housing managers

Climate change and the rental sector: Mapping the legislative and policy context: Local Government

The Briefing Paper series of the ‘Rental housing, climate change and adaptive capacity: a case study of Newcastle NSW’ project seeks to provide readers with access to current research on rental sector adaptation to climate change. Briefing Papers produced by the project team are working documents that provide a forum on theoretical, methodological and practical issues related to climate change adaption in rental housing. The project is funded by the National Climate change Adaptation Facility (NCCARF) for 2012. The publication as a ‘Briefing Paper’ does not preclude subsequent publication in scholarly journals, books or reports. Unless otherwise stated, ‘Rental housing, climate change and adaptive capacity’ publications are presented as contributions to debate and discussion and represent our developing thinking about the research. We are hoping that they may facilitate feedback from readers, researchers, renters and housing managers

A comparison of males and females&apos; temporal patterning to short-and long-term heat acclimation

The current study assessed sex differences in thermoregulatory and physiological adaptation to short-term (STHA) and long-term heat acclimation (LTHA). Sixteen (eight males; eight females) participants performed three running heat tolerance test

Explicit solutions to the Korteweg-de Vries equation on the half line

Certain explicit solutions to the Korteweg-de Vries equation in the first quadrant of the $xt$-plane are presented. Such solutions involve algebraic combinations of truly elementary functions, and their initial values correspond to rational reflection coefficients in the associated Schr\"odinger equation. In the reflectionless case such solutions reduce to pure $N$-soliton solutions. An illustrative example is provided.Comment: 17 pages, no figure

Convergence Behaviour of Growth Triangle: The Case of IMT-GT

Regional disparities and their evolution displayed a vital economic as well as political issue for most regions or countries (Blizkovsky, 2012). Due to realizing this shocking fact, it has drawn a lot of attention from all over the world to tackle this issue in order to avoid its adverse implication towards holistic economic development. The beauty of Indonesia-Malaysia-Thailand Growth Triangle (IMT-GT) is that it aims to increase the trade and investment among the three regions as it pursues private sector-led economic growth. However, evidence shows that the progress of development in this sub-region is either stagnant or slow. Hence, the aim of this study is to investigate the convergence hypothesis of the participating states and determine the reason behind each of the convergence behaviour portrayed. Non-linear time varying factor model namely Phillip and Sul has been employed in this study. The result implies that Negeri Sembilan is the only diverging group while the rest is converging. This phenomenon indicates that most of the states and provinces in this sub-region have positive performance towards the economic growth. Effective development planning can be done by policy makers after determining the performance of each of the states and provinces

Exploring the impact of population density on journey‐to‐crime in cases of stranger sexual assault and stranger homicide

The purpose of this research is to further understanding of how environmental factors impact on the distance an offender travels from their home to their crime scene - the so called ‘journey-to-crime’ (JTC.). Currently, Geographic Profilers rely on relatively generic JTC research to form inferences about the likely distance travelled by an offender, and may be missing the opportunity to make a more bespoke assessment which takes these factors into account. 1186 cases of female stranger sexual assault (Study 1) and 124 cases of stranger homicide (Study 2) were analysed. Euclidean measurement of distance was provided from the offender's recorded home to 3 crime site locations: (1) the initial contact with victim, (2) the assault/murder, and (3) the victim release/body disposal. Each crime site location was coded according to: (a) population density and (b) urban or rural. Initial analysis examined the median distance travelled from an offender's residence to the three different crime site locations. Significant findings for stranger sexual assaults indicated that the initial contact location was significantly further from an offender's residence compared to the sexual assault and victim release location. This was not replicated for stranger homicide offences. Both sexual assault and homicide cases revealed that the distance travelled to the ‘initial approach’ location did not differ according to population density, or whether the location was urban or rural. Regarding ‘sexual assault’ locations, offenders were found to travel significantly further from their home to attack their victim in low population density and rural areas. Results showed that both sexual assault and homicide offenders travelled significantly further from their home to the ‘victim release/body disposal’ site in low population density areas and rural areas. These findings have important, practical applications for investigations, allowing Geographic Profilers to provide more bespoke inferences about an offender's journey to crime