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

Donepezil’s Effect on Cardiac Function in Patients with Alzheimer’s Disease through an In Vivo, Non Invasive Measure of Cardiac Autonomic Function

The aim of the current study was to explore the effects of the medication Donepezil (Aricept®) on cardiac autonomic function for individuals diagnosed with mild to moderate (probable) Alzheimer’s disease (AD). Using age (± 3 years) and gender matched controls, differences in heart rate variability (HRV) among individuals with Alzheimer’s disease were compared to healthy controls over a period of six months (session 1 [baseline], session 2 [3 months], and session 3 [6 months]) in both supine and standing positions. HRV was obtained through frequency-domain (Low Frequency Power, High Frequency Power, RMSSD, LF/HF Ratio) and time-domain (six minutes) measures using ECG technology. Data were analyzed using 2x2x2 (AD group n= 12; HC group n= 12) and 2x2x3 (AD group n= 8; HC group n= 8) repeated measures ANCOVA’s while controlling for age, gender, body mass index (BMI), blood pressure, medications, dose of Donepezil (Aricept®), alcohol use, caffeine use, and physical activity. Results from the ANCOVA did not reveal statistically significant between group differences for the HRV frequency-domain measures. However, data indicated a trend towards greater reductions in normalized high frequency power (parasympathetic depression) and greater increases in normalized low frequency power (sympathetic exacerbation) among the AD group versus healthy controls at all three time points despite the use of Donepezil (Aricept®)

Income tax for primary producers

Increased farm incomes of the past two years and recent changes in income tax provisions have aroused enquiry concerning taxation for primary producers. Most farmers who have had preliminary March, 1975, income plus provisional tax assessments made have been astonished by the size of their likely commitment. This article explains the taxation provisions applying to primary producers and gives an example of how tax is calculated, showing why March, 1975, will be a time of reckoning for many farmers

Costs of grain storage on farms

GRAIN storage on farms has been commonly practised for intensive livestock production, for feed reserves, for seed purposes, and more recently to store excess grain. For most of these purposes permanent storage facilities are required

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 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, 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