Numerical Studies of Three-dimensional Breakdown in Trailing Vortex Wakes

Finite element, three dimensional relaxation methods are used to calculate the development of vortex wakes behind aircraft for a considerable downstream distance. The inclusion of a self-induction term in the solution, dependent upon local curvature and vortex core radius, permits calculation of finite lifetimes for systems for which infinite life would be predicted two dimensionally. The associated computer program is described together with single-pair, twin-pair, and multiple-pair studies carried out using it. It is found, in single-pair studies, that there is a lower limit to the wavelengths at which the Crow-type of instability can occur. Below this limit, self-induction effects cause the plane of the disturbance waves to rotate counter to the vortex direction. Self induction in two dimensionally generated twin spiral waves causes an increase in axial length which becomes more marked with decreasing initial wavelength. The time taken for vortex convergence toward the center plane is correspondingly increased. The limited parametric twin-pair study performed suggests that time-to-converge increases with increasing flap span. Limited studies of Boeing 747 configurations show correct qualitative response to removal of the outer flap and to gear deployment, as compared with wind tunnel and flight test experience

Changes in yield and composition of barley, wheat and triticale grains harvested during advancing stages of ripening

peer-reviewedThis study involved an evaluation of the changes in grain yield, nutritive value, ensilability and harvesting losses of intensively managed winter cereals harvested during the advancing stages of ripening. Five cereal crops (barley cv. Regina and wheat cv. Madrigal in 2001; barley cv. Regina, wheat cv. Falstaff and triticale cv. Fidelio in 2002) were assessed. Twenty plots per crop were arranged in a randomised complete block design, with five times of harvest (four for barley in 2002) and four replicate blocks per harvest. Dry matter (DM) yields changed relatively little between harvest dates, but fresh yields declined (P < 0.001) over time due to the moisture loss associated with ripening. Time-course changes in indices of nutritive value, such as concentrations of crude protein, starch and ash, and organic matter digestibility, were relatively small and did not follow a consistent pattern. Ensilability indices, such as DM and watersoluble carbohydrate concentrations and buffering capacity, indicated that satisfactory fermentations were likely if such crops were ensiled; buffering capacity, generally declining with advancing maturity. Harvesting losses were not clearly related to growth stage at harvest. It is concluded that winter cereal grain (barley, wheat and triticale) DM yields and quality were relatively constant as ripening progressed from DM concentrations of around 550 to >800 g/kg.One of the authors (P.S.) was in receipt of a Teagasc Walsh Fellowship

Exploratory studies of the cruise performance of upper surface blown configurations: Experimental program, high-speed pressure tests

Basic pressure data are presented which was obtained from an experimental study of upper-surface blown configurations at cruise. The high-speed (subsonic) experimental work, studying the aerodynamic effects of wing-nacelle geometric variations, was conducted around semi-span model configurations composed of diversified, interchangeable components. Power simulation was provided by high-pressure air ducted through closed forebody nacelles. Nozzle geometry was varied across size, exit aspect ratio, exit position and boattail angle. Both 3-D force and 2-D pressure measurements were obtained at cruise Mach numbers from 0.5 to 0.8 and at nozzle pressure ratios up to about 3.0. The experimental investigation was supported by an analytical synthesis of the system using a vortex lattice representation with first-order power effects. Results are also presented from a compatibility study in which a short-haul transport is designed on the basis of the aerodynamic findings in the experimental study as well as acoustical data obtained in a concurrent program. High-lift test data are used to substantiate the projected performance of the selected transport design

Exploratory studies of the cruise performance of upper surface blown configuration: Experimental program, high-speed force tests

The work to develop a wing-nacelle arrangement to accommodate a wide range of upper surface blown configuration is reported. Pertinent model and installation details are described. Data of the effects of a wide range of nozzle geometric variations are presented. Nozzle aspect ratio, boattail angle, and chordwise position are among the parameters investigated. Straight and swept wing configurations were tested across a range of nozzle pressure ratios, lift coefficients, and Mach numbers

Exploratory studies of the cruise performance of upper surface blown configurations. Experimental program: Test facilities, model design instrumentation, and lowspeed, high-lift tests

The model hardware, test facilities and instrumentation utilized in an experimental study of upper surface blown configurations at cruise is described. The high speed (subsonic) experimental work, studying the aerodynamic effects of wing nacelle geometric variations, was conducted around semispan model configurations composed of diversified, interchangeable components. Power simulation was provided by high pressure air ducted through closed forebody nacelles. Nozzle geometry was varied across size, exit aspect ratio, exit position and boattail angle. Three dimensional force and two dimensional pressure measurements were obtained at cruise Mach numbers from 0.5 to 0.8 and at nozzle pressure ratios up to about 3.0. The experimental investigation was supported by an analytical synthesis of the system using a vortex lattice representation with first order power effects. Results are also presented from a compatibility study in which a short haul transport is designed on the basis of the aerodynamic findings in the experimental study as well as acoustical data obtained in a concurrent program. High lift test data are used to substantiate the projected performance of the selected transport design

Experience of sleep disruption in primary Sjögren’s syndrome: A focus group study

Introduction: Primary Sjögren’s syndrome is the third most common systemic autoimmune rheumatic disease, following rheumatoid arthritis and systemic lupus erythematosus, and results in dryness, fatigue, discomfort and sleep disturbances. Sleep is relatively unexplored in primary Sjögren’s syndrome. We investigated the experiences of sleep disturbances from the viewpoint of primary Sjögren’s syndrome patients and their partners and explored the acceptability of cognitive behavioural therapy for insomnia. Method: We used focus groups to collect qualitative data from 10 patients with primary Sjögren’s syndrome and three partners of patients. The data were recorded, transcribed verbatim and analysed using thematic analysis. Results: Five themes emerged from the data: (a) Experience of sleep disturbances; (b) variation and inconsistency in sleep disturbances; (c) the domino effect of primary Sjögren’s syndrome symptoms; (d) strategies to manage sleep; (e) acceptability of evidence-based techniques. Sleep disturbances were problematic for all patients, but specific disturbances varied between participants. These included prolonged sleep onset time and frequent night awakenings and were aggravated by pain and discomfort. Patients deployed a range of strategies to try and self-manage. Cognitive behavioural therapy for insomnia was seen as an acceptable intervention, as long as a rationale for its use is given and it is tailored for primary Sjögren’s syndrome. Conclusion: Primary Sjögren’s syndrome patients described a range of sleep disturbances. Applying tailored, evidence-based sleep therapy interventions may improve sleep, severity of other primary Sjögren’s syndrome symptoms and functional ability

The impact of stroke: are people with aphasia different to those without?

Purpose. Stroke rehabilitation programmes aim to improve functional outcomes and quality of life. This study explored long-term outcomes in a cohort of people admitted to two acute stroke units with stroke. Comparisons were drawn between people with aphasia (PWA) and people without aphasia. Methods. People admitted to hospital with a first stroke were assessed at 2-weeks, 3-months and 6-months post-stroke. Measures included: the Barthel Index for Activities of Daily Living (ADL), the Frenchay Aphasia Screening Test, the General Health Questionnaire-12 for emotional well-being and the Stroke and Aphasia Quality of Life Scale-39g. Extended ADL and social support were also measured at 3 and 6 months, with the Frenchay Activities Index and the Social Support Survey, respectively. Results. Of 126 eligible participants, 96(76%) took part and 87(69%) were able to self-report. Self-report data are reported here. Although outcomes improved significantly across time, at 6 months people continued to experience substantial functional limitations (16% aphasic; 32% dependent on basic ADL); participation limitations (79% ≤30 on the FAI); high psychological distress (45%) and compromised quality of life (54% ≤4 on the SAQOL-39g). Levels of social support remained relatively stable. Though at 3-months post-stroke PWA were significantly more likely to experience high psychological distress (93% versus 50% for those without), across time, there were no significant differences between PWA and those without on psychological distress and also ADL and social support. There were, however, significant differences on extended ADL (F(1,68) = 7.80, p < 0.01) and quality of life (F(1,69) = 6.30, p < 0.05). Conclusion. PWA participated in fewer activities and reported worse quality of life after stroke than people without aphasia, even when their physical abilities, well-being and social support were comparable. Implications for clinical practice and future research are discussed

Field Performance and Quality of Hybrid Winter Wheat.

End of Project ReportAn assessment of hybrid winter wheat was carried out over three seasons to determine the commercial potential of hybrid varieties under Irish conditions. The studies examined the effects of reduced seeding rate on hybrid grain yield and quality in comparison to pure-line varieties. A comparison of the hybrid varieties available was also carried out and the higher yielding hybrids were then compared with the best pure-line varieties in terms of grain yield and quality, and response to fungicide. The results indicated that in good sowing conditions hybrids can give greater yields than pure-line varieties at reduced seeding rates, but the effect is not large or consistent. There was generally no effect of seeding rate on the grain quality of hybrid varieties but crop lodging occurred in one season at high seeding rates. Of the hybrid varieties examined, Mercury and Hyno Esta were the two better varieties in terms of grain yield; there was little difference between the hybrids examined in terms of grain quality. The best hybrid varieties did not give consistently higher yields or quality than the best pure-line varieties and exhibited a similar response to fungicide application as the pure-line varieties. It is concluded that when the price differential between seed of pure-line varieties and hybrid varieties is taken into account, the winter wheat hybrid varieties currently available do not offer any economic advantages to commercial growers at the present time

Predicting soil moisture conditions for arable free draining soils in Ireland under spring cereal crop production

peer-reviewedTemporal prediction of soil moisture and evapotranspiration has a crucial role in agricultural and environmental management. A lack of Irish models for predicting evapotranspiration and soil moisture conditions for arable soils still represents a knowledge gap in this particular area of Irish agro-climatic modelling. The soil moisture deficit (SMD) crop model presented in this paper is based on the SMD hybrid model for Irish grassland (Schulte et al., 2005). Crop and site specific components (free-draining soil) have been integrated in the new model, which was calibrated and tested using soil tension measurements from two experimental sites located on a well-drained soil under spring barley cultivation in south-eastern Ireland. Calibration of the model gave an R2 of 0.71 for the relationship between predicted SMD and measured soil tension, while model testing yielded R2 values of 0.67 and 0.65 (two sites). The crop model presented here is designed to predict soil moisture conditions and effective drainage (i.e., leaching events). The model provided reasonable predictions of soil moisture conditions and effective drainage within its boundaries, i.e., free-draining land used for spring cereal production under Irish conditions. In general, the model is simple and practical due to the small number of required input parameters, and due to model outputs that have good practical applicability, such as for computing the cumulative amount of watersoluble nutrients leached from arable land under spring cereals in free-draining soils

Chiral Behaviour of the Rho Meson in Lattice QCD

In order to guide the extrapolation of the mass of the rho meson calculated in lattice QCD with dynamical fermions, we study the contributions to its self-energy which vary most rapidly as the quark mass approaches zero; from the processes $\rho \to \omega \pi$ and $\rho \to \pi \pi$. It turns out that in analysing the most recent data from CP-PACS it is crucial to estimate the self-energy from $\rho \to \pi \pi$ using the same grid of discrete momenta as included implicitly in the lattice simulation. The correction associated with the continuum, infinite volume limit can then be found by calculating the corresponding integrals exactly. Our error analysis suggests that a factor of 10 improvement in statistics at the lowest quark mass for which data currently exists would allow one to determine the physical rho mass to within 5%. Finally, our analysis throws new light on a long-standing problem with the J-parameter.Comment: 13 pages, 7 figures. Full analytic forms of the self-energies are included and a correction in the omega-pi self-energ