ALBERT

Description: SUMMARYAn experiment, involving 68 female pigs, was undertaken to measure the effects of two diets differing in protein content, and of two patterns of feeding. The animals were housed in an enclosed building. The experiment extended through several parities; culled sows were replaced by gilts during the experiment, the whole course of which lasted 5 years.The diets were given at the rate of 1–8 or 2–3 kg per day throughout gestation, but the rate was reversed during the 5-week lactation so that, for litters of eight to nine pigs sows in each treatment group received the same quantity of food per parity. As a result of unsatisfactory performance, dietary composition was changed after 2 years so that for the last 3 years the digestible energy contents were higher.Treatments significantly influenced gestation live-weight gain, lactation weight loss and gestation backfat gain. The lower rate of gestation feeding was associated with low or negative gestation weight increases after the third to fourth litters, and a greater apparent rate of decline with increasing age in birth and 3-week weight per piglet. The high gestation, low lactation, rates of feeding led to slightly greater litter size and lower weaning weights per pig. A daily intake of 208 g crude protein and 8'3 g lysine appeared to meet the sow's requirements throughout gestation.In the pregnant sow feeding area, winter air temperatures were on average 16 °C below those in the summer, but were rarely below freezing point. Winter backfat gain was lower than, and gestation gain only half that in the summer. Litter size was also greater following summer pregnancies and 3-week weight per pig was greater following winter pregnancies. Independent of litter size, birth and 3-week weight per pig were positively correlated with gestation gain within treatment and season. The apparent positive correlation of litter size at 3 weeks with gestation backfat and weight gain was not found at birth. Litter size at birth was negatively correlated with gestation gain within season. The percentage of fertile matingswas less for matings between 1 September and 31 January. This coincided approximately with the reduced litter size (alive) which occurred following winter gestations.Lactation weight loss and 3-week weight per pig declined with increasing age of sow and the degree of weight loss was unrelated to subsequent litter size.The apparent effect of seasons and treatments on litter size at birth appeared not to be an obvious function of changes in live weight, which were also marked between seasons and treatments, but level of food intake in early gestation may have affected litter size independently. It was concluded that birth weight especially in the older sows, was associated with the rate of food intake in gestation, and possibly also in lactation, and with gestation empty weight gain.

Description: The U.S. Geological Survey, at the Denver Federal Center, Lakewood, Colorado assays C14 concentration of water samples using liquid scintillation techniques. The laboratory synthesizes benzene from precipitated barium carbonate using techniques described by Noakes, Kim, and Akers (1967). Three ml of the synthesized benzene is pipetted into a tared, low potassium-40 glass vial. The sample is weighed and 1ml of a scintillation solution is added to the vial. The scintillation solution used is a mixture of 10g PPO and 0.025g dimethyl-POPOP scintillators in 250ml toluene. Calculations of dates are made with the radiocarbon half-life of 5568 years; plus or minus numbers quoted herein are the standard error for the counting of radioactive disintegrations.

Description: A theoretical analysis has been made of turbulent viscous interaction on iso-thermal surfaces at hypersonic speeds. The important parameters governing the effects of incidence and displacement have been obtained under both strong and weak interaction conditions for flat-plate flows. A more general expression relating boundary-layer growth to the external pressure field and effective body shape has been obtained. The method is applied to the wedge compression corner problem and the results compared with some experimental data. © 1974, Cambridge University Press. All rights reserved.

Description: We observed a gradual change in the structure of a shock wave passing through a long tube of bubbly liquid, which we attribute to the motion of the bubbles relative to the liquid. We show that the effect of the motion on the structure of a shock wave is like that of thermal relaxation on gasdynamic shock waves: the pertinent relaxation time is the time viscous forces in the fluid take to alter the velocity of a bubble to that of the fluid. Our theory predicts certain changes in the speed of the shock wave and in its structure. We could not verify the prediction as to wave speed: in dilute mixtures it is too small to be measured. But we report experiments on the structure of the wave, which support our theoretical conclusion that the observed changes are due to the relative motion. © 1974, Cambridge University Press. All rights reserved.

Description: We discuss the theory of Kelvin wave propagation along an infinitely long coast-line which is straight except for small deviations which are treated as a stationary random function of distance along the coast. An operator expansion technique is used to derive the dispersion relation for the coherent Kelvin wave field. For the subinertial case σ = ω/f 〈 1 (ω = wave frequency, f = Coriolis parameter), it is shown that the wave speed is always decreased by the coastal irregularities. Moreover, while the coherent wave amplitude is unaltered, the energy flux along the coast is decreased by the irregularities. For the case σ 〉 1, however, we show that in the direction of propagation the wave is attenuated (with the energy being scattered into the random Poincaré and Kelvin wave modes) and that the wave speed is again decreased. Applications of the theory are made to the California coast and North Siberian coast to determine the decrease in phase velocity due to small coastal irregularities. For the California coast the percentage decrease is only about 1%. For the Siberian coast, however, the percentage decrease is about 25% for the K1 tide, and a minimum of 25% for the M2 tide. The attenuation of a Kelvin wave, however, appears to be due to very large scale irregularities. An estimate of the actual attenuation rate is not possible, though, because of the relatively short extent of coastal contours available for spectral analysis. Although attention in this paper has been focused on Kelvin wave propagation, the method developed could readily be used to study the behaviour of other classes of waves trapped against a randomly perturbed boundary. © 1974, Cambridge University Press. All rights reserved.

Description: Mean velocity and mean turbulent field measurements are performed for the case of a three-dimensional turbulent boundary layer on an axially rotated cylinder. The cylinder model consists of two parts: a stationary section followed by a spinning afterbody. Techniques of hot-wire anemometry are employed, which yield complete mean velocity and turbulence measurements in skewed flows. The general behaviour of the three-dimensional boundary layer is first discussed: two asymptotic layers analogous to the two-dimensional wall and defect layers are observed; they are shown to evolve from the equations of mean motion. The hypothesis of scalar eddy viscosity is investigated in the light of these results. Using conventional length scale assumptions together with the Reynolds stress tensor equations, a prediction of curvature effects in the law of the wall region is developed; a result in the present case is a smaller slope of the semi-logarithmic portion of the law of the wall, No assumptions over and above those necessary for plane, two-dimensional flow are required for this analysis. The geometry of the model is such that a rapid change in mean rate of strain occurs along the streamlines. From the history of the components of the [formulla omitted] tensor, it is possible to draw some fundamental conclusions concerning the dynamics of the energy dissipation, diffusion and redistribution processes. © 1974, Cambridge University Press. All rights reserved.

Description: The physics problems remaining to be solved to achieve practical fusion power by magnetic confinement techniques are believed to be well posed and soluble. A programme plan recently developed in the United States calls for progressively larger plasma confinement experiments to address these physics questions in line with a serious programme in fusion power engineering. Implementation of the plan is expected to lead to the first production of power from a deuterium–tritium-fuelled system in 1980. Thereafter, three progressively larger experimental electrical power reactors are planned, leading to fusion power commercialization in the later 1990s.The environmental characteristics of fusion reactors have been estimated by analyzing conceptual reactor designs. It is projected that the only volatile radioactive material in a fusion power-plant will be the tritium fuel. Analyses indicate that tritium leakage can be held to very low levels and accordingly should not pose a significant environmental hazard.Careful selection of the materials of construction of a fusion reactor core will minimize radioactivity induced by neutron activation. This activity will be nonvolatile, and it can be isolated from the environment by the use of existing techniques. Because this induced activity is short-lived, it does not represent a long-term storage problem.Anticipated thermal efficiencies of fusion powerplants range from present-day levels (30–40%) using standard conversion systems to about 50% when more exotic techniques (such as liquid-metal topping cycles) are utilized.

Description: SummaryThe flavour of meat from sheep grazing rape (Brassica napusL.) was compared with that from grass-fed sheep in a series of experiments. The occurrence of a strong and unattractive foreign flavour and aroma was confirmed but the intensity of flavour was not consistent. The intensity was apparently unaffected by cultivar, growth stage, length of grazing period or breed or age of sheep.

Description: SUMMARYSeventy-nine pregnant Merino ewes grazing pasture at two intensities were slaughtered in groups at intervals from 60 days after conception to post-partum. Sixty-one nonpregnant ewes were also slaughtered. The weights of various organs including uteri and their contents were recorded and the energy content of each ewe was determined.The weight of uterine contents (conceptus) increased rectilinearly with increasing foetal age to 100 days: differences between singles and twins were not significant. From 100 days to term, the relationship was also rectilinear but the slope was greater: a more rapid increase occurred with twins than with singles (P 〈 0·05). The nutritional difference imposed did not affect the relationship.A regression of total energy reserve on live weight (less fleece and conceptus) was established. Differences between this relationship and those established separately for non-pregnant, pregnant and post-partum ewes were not significant.The contribution of changes in conceptus weight to live-weight changes in gravid ewes is discussed.

Description: SummaryTwo groups of mafic dikes occur within a terrain of metasomatic granitic rocks and quartzofeldspathic gneiss in the central Bighorn Mountains of Wyoming. The younger group consists of dolerite dikes which possess ophitic, subophitic, hypidio morphic-granular and microporphyritic textures. Mineralogically, the dolerites consist primarily of plagioclase (average An 54), augite (average Ca: Mg: Fe = 41: 43: 16) and uralite. The older dikes are metadolerites which possess granoblastic margins that grade into interiors characterized by relict subophitic and locally, porphyriti texture. Dike margins consist of fresh plagioclase and hornblende primarily. Interiors are principally clouded plagioclase (average An 46), augite (average Ca: Mg: Fe = 39: 54: 7) and uralite and/or hornblende. Textural, mineralogic and chemical data indicate that the meta-dolerites were derived from an earlier generation of mafic dikes comparable to the unmeta-morphosed dolerites in the area. The dikes were metamorphosed under low amphibolite facies conditions during the last regional metamorphic event which affected the country rock. During their metamorphism, minimal amounts of water from the country rock facilitated the total recrystallization of the metadolerite margins and the complete or nearly complete replacement of pyroxene by hornblende in the margins. In general, dike interiors underwent no textural changes other than partial destruction of the original subophitic plagioclase–pyroxene relationship as the pyroxene was replaced peripherally by hornblende. This process was accompanied by diffusion of calcium from the plagioclase to form the hornblende, and by diffusion of iron from the augite to cause the clouding of adjacent plagioclase.