Compression failure of angle-ply laminates

The present work deals with modes and mechanisms of failure in compression of angle-ply laminates. Experimental results were obtained from 42 angle-ply IM7/8551-7a specimens with a lay-up of ((plus or minus theta)/(plus or minus theta)) sub 6s where theta, the off-axis angle, ranged from 0 degrees to 90 degrees. The results showed four failure modes, these modes being a function of off-axis angle. Failure modes include fiber compression, inplane transverse tension, inplane shear, and inplane transverse compression. Excessive interlaminar shear strain was also considered as an important mode of failure. At low off-axis angles, experimentally observed values were considerably lower than published strengths. It was determined that laminate imperfections in the form of layer waviness could be a major factor in reducing compression strength. Previously developed linear buckling and geometrically nonlinear theories were used, with modifications and enhancements, to examine the influence of layer waviness on compression response. The wavy layer is described by a wave amplitude and a wave length. Linear elastic stress-strain response is assumed. The geometrically nonlinear theory, in conjunction with the maximum stress failure criterion, was used to predict compression failure and failure modes for the angle-ply laminates. A range of wave length and amplitudes were used. It was found that for 0 less than or equal to theta less than or equal to 15 degrees failure was most likely due to fiber compression. For 15 degrees less than theta less than or equal to 35 degrees, failure was most likely due to inplane transverse tension. For 35 degrees less than theta less than or equal to 70 degrees, failure was most likely due to inplane shear. For theta less than 70 degrees, failure was most likely due to inplane transverse compression. The fiber compression and transverse tension failure modes depended more heavily on wave length than on wave amplitude. Thus using a single parameter, such as a ratio of wave amplitude to wave length, to describe waviness in a laminate would be inaccurate. Throughout, results for AS4/3502, studied previously, are included for comparison. At low off-axis angles, the AS4/3502 material system was found to be less sensitive to layer waviness than IM7/8551-7a. Analytical predictions were also obtained for laminates with waviness in only some of the layers. For this type of waviness, laminate compression strength could also be considered a function of which layers in the laminate were wavy, and where those wavy layers were. Overall, the geometrically nonlinear model correlates well with experimental results

The timeliness of UK private company financial reporting:Regulatory and economic influences

This paper investigates the extent to which the timeliness of UK private companies’ accounting information reflects regulatory and economic influences by studying the impact of a one month shortening of the statutory regulatory filing deadline. Using the financial reporting lag and propensity to file late as measures of timeliness, we find that although reporting behaviour is largely driven by regulatory deadlines, companies conjectured to be producing accounting information for reporting to outside investors publish their accounts significantly more quickly, and are substantially less likely to file beyond the statutory deadline (late), than their counterparts lacking similar incentives. However, in terms of this reporting lag differential, the change in regulation had a homogeneous impact. We report a significant reduction in the mean and median filing time, but an increase of 46% in the proportion of firms filing late, in the year following the regulatory change. Our results are robust to the employment of a number of different estimation methods, including matching and Huber and median regressio

Digital Histories of Crime and Research-Based Teaching and Learning

The proliferation of digitised primary sources has created exciting possibilities for those of us teaching undergraduate modules on crime and punishment in nineteenth century England and Wales. In this article, we reflect on our experience of devising and running a ‘special subject’ at the University of Liverpool in which we encourage our students to see themselves as active, independent researchers - as producers, rather than passive consumers, of knowledge. Working on individual projects in a group of 15, students tackle the different stages of the research process side-by-side, discussing issues of research design, record-linkage and the interpretation and analysis of primary and secondary sources with each other as well as with members of staff and PhD students. In our experience, this approach leads to very high levels of student engagement. It also provides invaluable, ‘hands-on’ research training for final year undergraduates as they prepare to embark on their dissertations

Making a place: women in the "workers' city"

Beginning with a description of Elizabeth, an outer suburb of Adelaide, as a ‘ workers’ city, this paper asserts the central importance of women's activities, whether in households or wider territories, in the making, defining and defending of place. Against the notion that Elizabeth and places like it were ‘ working man's towns', the paper argues that while men's capabilities as workers and breadwinners were important, it was women within working-class households who performed the more difficult tasks of translating male wages (and their own earnings) into valuable outcomes. In this sense, women organised the successful use of the resources provided by a planned community and the relative prosperity of the post-war long boom. Women also managed the 'outside of the home, its links with the public sphere and with external authorities ranging from credit providers to welfare and tenancy officers as well as its articulation to largely female-maintained neighbourhood and kin coalitions. Accordingly, Elizabeth relied very much on the vigilance and capacity of women. Finally, the paper suggests that the important role now played by women activists in Elizabeth and other working-class suburbs which suffered recession and economic decline since the 1970s is neither simply a product of poverty nor a dramatically new feature of working-class life, but an extension of that established responsibility for local standards and local security, in the context of increased opportunities for participation and for the creation of women' s institutions and initiatives. There are clear implications in this for any attempt to understand, consult or intervene in working-class communities.Australian Policy Online (APO)'s Linked Data II project, funded by the Australian Research Council, with partners at the ANU Library, Swinburne University and RMIT

Planning the good city in Australia : Elizabeth as a new town

This paper describes the planning of Elizabeth by the South Australian Housing Trust. As a new town, Elizabeth drew on the planning assumptions and objectives of the postwar British town planning movement and represented a specific plagiarization of the empowering British tradition which dominated Australian planning. In particular, the planners of Elizabeth assumed that working-class residents could be 'improved' by a proper arrangement of urban space and would not bring their own spatial creativity to bear upon the community, and that the major employers enticed into locating in the new town would also conform to the expectations of a harmonious as well as profitable landscape. Both assumptions were vital in the new town vision, yet neither had any force outside the planning ideologies themselves. The building of the city reflected the difficulty of implementing borrowed templates for the 'good city', especially in terms of 'self-containment' and 'social mix'. Increasingly wary of the unauthorised activities of residents and doubtful about the means of creating a cohesive and mixed community, the Trust 's officials instead began to rely heavily on employers to guarantee the social as well as economic outcomes of the project . The paper concludes by suggesting that while economic prosperity and the benefits of Trust planning kept employers loyal to this accumulation site while providing residents with the means to build a working community into the early 1970s, the onset of crisis fatally undermined this version of the 'good city'.Australian Policy Online (APO)'s Linked Data II project, funded by the Australian Research Council, with partners at the ANU Library, Swinburne University and RMIT

Evaluation report for the Centre for Fun and Families (August 1999-March 2002)

The purpose of this report is two fold, to provide an evaluation of the long-term effectiveness of two complementary training programmes run by the Centre for Fun and Families, Living with Teenagers and Avoiding Conflict with Adults and to contribute to the research and record of evidence-based practice in support of the Youth Justice Board Parenting Programme (YJBPP)

Determinants of Feedlot Cattle Death Loss Rates

Death loss in feedlot cattle can have significant impacts on feedlot profitability. Not only does death loss result in foregone revenue, but the operation still incurs the costs to date associated with those animals. This study uses pen-level feedlot data from a private feed-lot in the Southern Great Plains. Both company- owned and customer retained ownership cattle are included in the data set. A Tobit model is used to analyze pen characteristics’ influence on death loss in feedlot cattle, including cattle characteristics, source characteristics, management characteristics, and treatment incidence. Results imply that several pen characteristics impact death loss and that cattle source, in terms of both cattle source geographic location and market source type, has a significant influence on death loss rate

Caffeine ingestion compromises thermoregulation and does not improve cycling time to exhaustion in the heat amongst males

Purpose Caffeine is a commonly used ergogenic aid for endurance events; however, its efficacy and safety have been questioned in hot environmental conditions. The aim of this study was to investigate the effects of acute caffeine supplementation on cycling time to exhaustion and thermoregulation in the heat. MethodsIn a double-blind, randomised, cross-over trial, 12 healthy caffeine-habituated and unacclimatised males cycled to exhaustion in the heat (35 °C, 40% RH) at an intensity associated with the thermoneutral gas exchange threshold, on two separate occasions, 60 min after ingesting caffeine (5 mg/kg) or placebo (5 mg/kg). ResultsThere was no effect of caffeine supplementation on cycling time to exhaustion (caffeine; 28.5 ± 8.3 min vs. placebo; 29.9 ± 8.8 min, P = 0.251). Caffeine increased pulmonary oxygen uptake by 7.4% (P = 0.003), heat production by 7.9% (P = 0.004), whole-body sweat rate by 21% (P = 0.008), evaporative heat transfer by 16.5% (P = 0.006) and decreased estimated skin blood flow by 14.1% (P 0.05). ConclusionThe greater heat production and storage, as indicated by a sustained increase in core temperature, corroborate previous research showing a thermogenic effect of caffeine ingestion. When exercising at the pre-determined gas exchange threshold in the heat, 5 mg/kg of caffeine did not provide a performance benefit and increased the thermal strain of participants

Factors contributing to the change in thermoneutral maximal oxygen consumption after iso-intensity heat acclimation programmes

The factors explaining variance in thermoneutral maximal oxygen uptake (V ̇O2max) adaptation to heat acclimation (HA) were evaluated, with consideration of HA programme parameters, biophysical variables and thermo-physiological responses. Seventy-one participants consented to perform iso-intensity training (range: 45%-55% V ̇O2max) in the heat (range: 30°C-38°C; 20%-60% relative humidity) on consecutive days (range: 5-days-14-days) for between 50-min and-90 min. The participants were evaluated for their thermoneutral V ̇O2max change pre-to-post HA. Participants’ whole-body sweat rate, heart rate, core temperature, perceived exertion and thermal sensation and plasma volume were measured, and changes in these responses across the programme determined. Partial least squares regression was used to explain variance in the change in V ̇O2max across the programme using 24 variables. Sixty-three percent of the participants increased V ̇O2max more than the test error, with a mean±SD improvement of 2.6 ± 7.9%. A two-component model minimised the root mean squared error and explained the greatest variance (R2; 65%) in V ̇O2max change. Eight variables positively contributed (P < 0.05) to the model: exercise intensity (%V ̇O2max), ambient temperature, HA training days, total exposure time, baseline body mass, thermal sensation, whole-body mass losses and the number of days between the final day of HA and the post-testing day. Within the ranges evaluated, iso-intensity HA improved V ̇O2max 63% of the time, with intensity- and volume-based parameters, alongside sufficient delays in post-testing being important considerations for V ̇O2max maximisation. Monitoring of thermal sensation and body mass losses during the programme offers an accessible way to gauge the degree of potential adaptation