17,748 research outputs found
Comparison of Experimental and Analytical Performance for Contoured Endwall Stators
Comparisons between predicted and experimental stator losses showed that the analysis was able to predict the change in stator loss when contoured endwalls with highly three dimensional passage geometry were used. The level of loss was predicted to within 75 percent of that measured. The predicted loss was due only to profile loss and boundary layer growth on the endwalls. The 25 percent difference was approximately 0.015 at design pressure ratio. The analysis was shown to predict the trend in stator flow angle, even for small stator geometries
A Duality Approach to Testing the Economic Behaviour of Dairy-Marketing Co-operatives: The Case of Ireland
The main objectives of this paper are: (i) to establish whether Irish dairy marketing cooperatives behaved "as if" they were profit maximisers over the period 1961 to 1987 and (ii) to determine the response of the sector to the imposition of the milk production quota in 1984. The theory of the cooperative managed firm (CMF) is first recast in a duality framework. The CMF differs from the profit maximising firm (PMF) in (a) having as its objective the aximisation of the price paid to its members for the raw material they supply and (b) being obliged to process all the raw material supplied by its members. A formal test as to whether the Irish dairy-processing sector could be characterised as "virtual" profit maximisers was implemented and could not be rejected. This finding was reinforced by our finding that the elasticity of milk price with respect to the volume of milk processed was zero. Milk price was found to be driven mainly by exogenous changes in the price of processed output. The impact of the quota was to obviously reduce the level of processed output but not proportionately. Our results suggest that every 10% fall in the amount of milk processed reduces processed output of the sector by 6%. We also found a negative relationship between the amount of the milk raw material processed and the demand for labour implying that the introduction of the quota would not of itself have adversely affect employment in the sector.co-operative; duality theory; initial profit maximisation; production quotas
Effects of dietary fibre and the provision of a foraging substrate on the welfare of sows in different grouping systems
End of project reportThere are no clear guidelines on how best to meet the EU legislative requirement (Council Directive 2001/88/EC) that pregnant sows and gilts should be provided with sufficient amounts of bulky or high fibre diets and high energy food to satisfy hunger and the motivation to chew. Therefore the aim of this project was to investigate the effect of increasing dietary fibre levels and providing access to a foraging substrate on the welfare of sows housed in dynamic and static groups. To achieve this a review paper was compiled and three experiments were conducted.
The aim of the review paper was to assess the effectiveness of increasing dietary fibre levels on the welfare of pregnant sows. Previous research found that increasing dietary fibre levels decrease activity levels and the performance of stereotypic behaviour, and increase resting behaviour. However, high fibre diets do not appear to reduce aggression between group-housed pregnant sows. The research clearly showed that the effectiveness of high fibre diets is influenced by the source of fibre, with soluble fibres being more effective in reducing stereotypic behaviours than insoluble fibres. However the optimum fibrous ingredient, or combination of ingredients, and the optimum dietary inclusion rate for these ingredients remains unclear
A theoretical approach to the determination of magnetic torques by near field measurement
Theoretical approach to determination of magnetic torques on orbiting spacecraft by near-field measuremen
The effect of turning frequency on in-vessel compost processing and quality
Composting is one way to contribute to the zero waste initiative on the University of Arkansas (UA) campus. In-vessel systems like Earth Tubs™ are purported to provide better control of temperature and moisture during the composting process, and have screw augers for turning materials, which helps facilitate microbial activity and thermophilic composting. The goal of this research was to determine if turning frequency affects processing or final quality of compost made with pre- and post-consumer food waste feedstock and a wood chip bulking agent. Turning frequencies (treatment) of 3 days/week and 7 days/week were evaluated over time throughout three vessel filling and composting processes. Temperature, pH, electrical conductivity (EC), and moisture content (MC) were measured weekly during vessel filling. When the vessels reached one half to two thirds volumetric capacity, the compost entered a 30-day composting period during which no food waste or wood chips were added to the vessels. Turning of the food waste continued. Additionally, total C, N, C:N ratio, and hot water extractable C (HWEC) and N (HWEN) were measured at the conclusion of composting. Recommended ranges and values for temperature, pH, MC, and total C:N ratio are all possible to reach when composting with Earth Tubs™, but there is little to no effect of 3 days/week versus 7days/week treatment on final quality of compost, and quality is not consistent over time between runs. The Earth Tub™ systems were not equipped to complete composting within a 3 week period, as composting took between 10-32 weeks in each of the three runs. For large-scale composting of food waste feedstock with wood chip bulking agents on the UA campus, more research would need to be done to assess whether Earth Tubs™ are a viable option, and whether the logistics of having the vessels off-site lend themselves to a sustainable campus-wide composting program
Book Review: Convent Life in Colonial Mexico: A Tale of Two Communities
Review of Convent Life in Colonial Mexico: A Tale of Two Communities by Stephanie L. Kir
Do Quasars Lens Quasars?
If the unexpectedly high frequency of quasar pairs with very different
component redshifts is due to the lensing of a population of background quasars
by the foreground quasar, typical lens masses must be \sim10^{12}M_{\sun} and
the sum of all such quasar lenses would have to contain times the
closure density of the Universe. It then seems plausible that a very high
fraction of all \sim10^{12} M_{\sun} gravitational lenses with redshifts
contain quasars. Here I propose that these systems have evolved to
form the present population of massive galaxies with M and M
>5\times10^{11} M_{\sun}.Comment: 6 pages, aas style, ams symbols, ApJL (accepted
Perceptions and correlates of peer-victimization and bullying
The experiences of peer-victimization and bullying are often treated empirically as though they are conceptually indistinct. Both involve repeated aggression,but definitions of bullying additionally emphasize the importance of aggressor intent and imbalance of power between the aggressor and the victim (Olweus, 1978; Whitney & Smith, 1993). The present study aimed to examine the extent to which peer-victimization and bullying are empirically similar. The sample comprised 1,429 pupils (50.2% male) aged between 8 and 13 years attending mainstream Scottish schools. Self-report questionnaire assessing peer-victimization and bullying, copingstrategy use (WCCL: Hunter, 2000), situational appraisal and depressive symptomatology (Birleson, 1981). Almost one-third (30.7%) of pupils reported experiencing peer-victimization, and of these 38.1% (11.7% of whole sample) were categorized as victims of bullying. Victims of bullying perceived higher levels of threat and lower levels of perceived control. They also reported using more Wishful Thinking and Social Support coping strategies, but did not differ on Problem Focused coping. Bullied pupils also reported higher levels of depressive symptomatology. Peer-victimization and bullying appear to be qualitatively different experiences for children and adolescents, with bullying being the more serious phenomenon
Analytical and experimental investigation of stator endwall countouring in a small axial-flow turbine
An experimental and analytical investigation was conducted to determine the effect of stator endwall contouring on turbine stage performance. In this investigation three stator configurations were evaluated using a common rotor. The three stator configurations were a cylindrical endwall design and two contoured endwall designs, one having a S-shaped outer wall profile and the other having a conical-shaped outer wall profile. Experimental data were obtained over a range of equivalent speeds, total pressure ratios, and rotor tip clearances for each stator-rotor combination. Detailed analytical loss assessments were conducted to aid in the determination of the contouring effect on turbine performance
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