Flight Tests on U.S.S. Los Angeles. Part I : Full Scale Pressure Distribution Investigation

The primary purpose of this investigation was to obtain simultaneous data on the loads and stress experience in flight by the U. S. S. Los Angeles which could be used in rigid airship structure design. A secondary object of the investigation was to determine the turning and drag characteristics of the airship. The aerodynamic loading was obtained by measuring the pressure at 95 locations on the tail surfaces, 54 on the hull, and 5 on the passenger car. These measurements were made during a series of maneuvers consisting of turns and reversals in smooth air and during a cruise in rough air which was just short of squall proportions. The results of the pressure measurements on the hull indicate that the forces on the forebody of an airship are relatively small. The tail surface measurements show conclusively that the forces caused by gusts are much greater than those caused by horizontal maneuvers. In this investigation the tail surface loadings caused by gusts closely approached the designed loads of the tail structure. The turning and drag characteristics will be reported in separate reports

Speed and Deceleration Trials of U.S.S. Los Angeles

The trials reported in this report were instigated by the Bureau of Aeronautics of the Navy Department for the purpose of determining accurately the speed and resistance of the U. S. S. "Los Angeles" with and without water recovery apparatus, and to clear up the apparent discrepancies between the speed attained in service and in the original trials in Germany. The trials proved very conclusively that the water recovery apparatus increases the resistance about 20 per cent, which is serious, and shows the importance of developing a type of recovery having less resistance. Between the American and the German speed trials without water recovery there remains an unexplained discrepancy of nearly 6 per cent in speed at a given rate of engine revolutions. Warping of the propeller blades and small cumulative errors of observation seem the most probable causes of the discrepancy. It was found that the customary resistance coefficients C, are 0.0242 and 0.0293 without and with the water recovery apparatus, respectively. The corresponding values of the propulsive coefficient K, are 56.7 and 44.6. If there is an error in these figures, it is probably in a slight overestimate of C, and an underestimate of K. The maximum errors are almost certainly less than 5 per cent. No scale effect was detected indicating variation of C with respect to velocity (author

First observation of 55,56Zn

In an experiment at the SISSI/LISE3 facility of GANIL, the most proton-rich zinc isotopes 55,56Zn have been observed for the first time. The experiment was performed using a high-intensity 58Ni beam at 74.5 MeV/nucleon impinging on a nickel target. The identification of 55,56Zn opens the way to 54Zn, a good candidate for two-proton radioactivity according to theoretical predictions.Comment: 2 pages, 1 figure, accepted for publication in Eur. Phys. J.

Decay of proton-rich nuclei between 39Ti and 49Ni

Decay studies of very neutron-deficient nuclei ranging from 39Ti to 49Ni have been performed during a projectile fragmentation experiment at the GANIL/LISE3 separator. For all nuclei studied in this work, 39,40Ti, 42,43Cr, 46Mn, 45,46,47Fe and 49Ni, half-lives and decay spectra have been measured. In a few cases, gamma coincidence measurements helped to successfully identify the initial and final states of transitions. In these cases, partial decay scheme are proposed. For the most exotic isotopes, 39Ti, 42Cr, 45Fe and 49Ni, which are candidates for two-proton radioactivity from the ground state, no clear evidence of this process is seen in our spectra and we conclude rather on a delayed particle decay.Comment: 12 pages, 15 figures, submitted for publication in Eur. Phys. J.

Quantum calculations of Coulomb reorientation for sub-barrier fusion

Classical mechanics and Time Dependent Hartree-Fock (TDHF) calculations of heavy ions collisions are performed to study the rotation of a deformed nucleus in the Coulomb field of its partner. This reorientation is shown to be independent on charges and relative energy of the partners. It only depends upon the deformations and inertias. TDHF calculations predict an increase by 30% of the induced rotation due to quantum effects while the nuclear contribution seems negligible. This reorientation modifies strongly the fusion cross-section around the barrier for light deformed nuclei on heavy collision partners. For such nuclei a hindrance of the sub-barrier fusion is predicted.Comment: accepted for publication in Physical Review Lette

Predição do consumo de matéria seca de cabras leiteiras durante a gestação.

Resumo: O período da gestação é caracterizado por importantes mudanças fisiológicas no corpo materno tais como a diminuição da ingestão de alimento no último terço de gestação em fêmeas com gestação de múltiplos fetos. O objetivo desse estudo foi desenvolver modelos para predizer a ingestão de matéria seca (IMS) em cabras durante gestação simples e gemelar. Parar este estudo, foram usadas 1820 observações de IMS, obtidos diariamente a partir de sete cabras com gestação gemelar e seis cabras com gestação simples a partir do primeiro dia até os 140 dias de gestação. A IMS diária foi ajustada em três modelos não lineares, os quais foram avaliados através do critério de informação Bayesiana (BIC) como um indicador de melhor ajuste do modelo aos dados. O modelo que melhor se ajustou aos dados foi o modelo quadrático, com valor de BIC de 11549. Os interceptos e coeficientes de regressões do modelo quadrático utilizado para predição do IMS diário foram diferentes entre gestação simples e gemelar (P< 0.01). Comparado as cabras com gestação simples, as cabras com gestação gemelar tiveram maior decréscimo na IMS durante a gestação. Esse decréscimo na IMS em fêmeas com gestação gemelar se deve principalmente a mudanças hormonais e a maior compressão ruminal causada pelo maior tamanho de seus úteros grávidos. Os modelos desenvolvidos nesse estudo devem de ser considerados no manejo nutricional de cabras leiteiras durante a gestação. [Prediction of dry matter intake of dairy goats during pregnancy]. Abstract: The pregnancy is characterized by important physiological changes in maternal body such as a decrease on feed intake in the last third of pregnancy mainly in pregnancy of multiples fetuses. The objective of this study was to develop a model to predict the dry matter intake (DMI) of dairy goats carrying single and twin fetuses throughout pregnancy. For this study it was used a total of 1820 individual records of DMI from seven goats carrying twins and six goats carrying single fetuses. The DMI was daily recorded from the first up to 140 days of pregnancy. The daily DMI as a proportion of the average BW was fitted to tree non-linear models which were evaluated considering the Bayesian information criterion (BIC) value as an indicator how well the model fit the data. The best model fitting the data was the quadratic model with had BIC value of 11549. The intercepts and the slopes of the quadratic models used to predict the daily DMI were different between litter sizes (P < 0.01). Goats carrying twin fetuses showed a greater decrease in the DMI during pregnancy compared to goats carrying single fetus. The decrease of feed intake in females carrying twins may be mainly related to hormonal changes and a greatest rumen compression due to the biggest size of the gravid uterus. The models developed in this study may be relevant in the adoption of nutritional management of dairy goats during the pregnancy

Star formation around RCW 120, the perfect bubble

We take advantage of the very simple morphology of RCW 120 -- a perfect bubble -- to understand the mechanisms triggering star formation around an HII region and to establish what kind of stars are formed there. We present 870 microns observations of RCW 120, obtained with the APEX-LABOCA camera. These show the distribution of cold dust, and thus of neutral material. We use Spitzer-MIPS observations at 24 and 70 microns to detect the young stellar objects (YSOs) present in this region and to estimate their evolutionary stages. A layer of dense neutral material surrounds the HII region, having been swept up during the region's expansion. This layer has a mass greater than 2000 solar masses and is fragmented, with massive fragments elongated along the ionization front (IF). We measured the 24 microns flux of 138 sources. Of these, 39 are Class I or flat-spectrum YSOs observed in the direction of the collected layer. We show that several triggering mechanisms are acting simultaneously in the swept-up shell, where they form a second generation of stars. No massive YSOs are detected. However, a massive, compact 870 microns core lies adjacent to the IF. A 70 microns source with no 24 microns counterpart is detected at the same position. This source is a likely candidate for a Class 0 YSO. Also at 24 microns, we detect a chain of about ten regularly spaced Class I or flat spectrum sources, parallel to the IF, in the direction of the most massive fragment. We suggest that the formation of these YSOs is the result of Jeans gravitational instabilities in the collected layer. Finally, the 870 microns emission, the 24 microns emission, and the Halpha emission show the existence of an extended and partially ionized photodissociation region around RCW 120.Comment: 14 pages, 17 figure