529 research outputs found

    Design of a fault tolerant airborne digital computer. Volume 2: Computational requirements and technology

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    This final report summarizes the work on the design of a fault tolerant digital computer for aircraft. Volume 2 is composed of two parts. Part 1 is concerned with the computational requirements associated with an advanced commercial aircraft. Part 2 reviews the technology that will be available for the implementation of the computer in the 1975-1985 period. With regard to the computation task 26 computations have been categorized according to computational load, memory requirements, criticality, permitted down-time, and the need to save data in order to effect a roll-back. The technology part stresses the impact of large scale integration (LSI) on the realization of logic and memory. Also considered was module interconnection possibilities so as to minimize fault propagation

    Laser-driven plasma waves in capillary tubes

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    The excitation of plasma waves over a length of up to 8 centimeters is, for the first time, demon- strated using laser guiding of intense laser pulses through hydrogen filled glass capillary tubes. The plasma waves are diagnosed by spectral analysis of the transmitted laser radiation. The dependence of the spectral redshift, measured as a function of filling pressure, capillary tube length and incident laser energy, is in excellent agreement with simulation results. The longitudinal accelerating field inferred from the simulations is in the range 1 -10 GV/m

    Geohazards analysis of Pisa tunnel in a fractured incompetent rocks in Zagros Mountains, Iran.

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    The Pisa 2 tunnel with 740 m in length and 20° N trend is located along the Kazerun fault zone in Simply Folded Belt of Zagros, Iran. This tunnel has been excavated in the fractured incompetent marl layers with high expansive pressure of up to 2 kg/cm2. In this study, the geological hazards along the tunnel have been recognized and categorized. This study revealed that, in the long-term usage of the tunnel, the lining did not endure against the loading and the secondary leakages. It is mainly attributed due to the non-efficiencies of drainage and isolation systems in the tunnel site. Therefore, it caused asphalt damage, drainage damage, and wall distortion. FLAC3D software has been used in this research. We conducted various analyses for pre-excavation stress states, syn-excavation, and post-excavation strain states. The results showed no indication of instability and critical deformations during the excavation time. It also revealed that due to the non-efficiencies of drainage and isolation systems against secondary leakages and consequently marl expansion, the volumetric and shear strains (i.e., expansions and displacements) have exceeded from the critical states of strain along the tunnel. For various remedy purpose, this paper attempted several measures that can be taken in order to modify the drainage and isolation systems along the tunnel area. The reconstruction of drainage systems with suitable reinforced concrete and adequate slope has been proposed. The width of channel and isolation of backside of lining and implementation of multi-order outlets (i.e., backside of lining) for draining of groundwater into where the main drainage systems are located in the tunnel gallery were suggested

    Relativistic nature of a magnetoelectric modulus of Cr_2O_3-crystals: a new 4-dimensional pseudoscalar and its measurement

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    Earlier, the magnetoelectric effect of chromium sesquioxide Cr_2O_3 has been determined experimentally as a function of temperature. One measures the electric field-induced magnetization on Cr_2O_3 crystals or the magnetic field-induced polarization. From the magnetoelectric moduli of Cr_2O_3 we extract a 4-dimensional relativistic invariant pseudoscalar α~\widetilde{\alpha}. It is temperature dependent and of the order of 10^{-4}/Z_0, with Z_0 as vacuum impedance. We show that the new pseudoscalar is odd under parity transformation and odd under time inversion. Moreover, α~\widetilde{\alpha} is for Cr_2O_3 what Tellegen's gyrator is for two port theory, the axion field for axion electrodynamics, and the PEMC (perfect electromagnetic conductor) for electrical engineering.Comment: Revtex, 36 pages, 9 figures (submitted in low resolution, better quality figures are available from the authors

    Effect of Protein Level, Lysine and Oats in Diets for Growing-Finishing Pigs

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    Previous research has shown that the protein content of swine diets can be reduced approximately two percent if the diet is supplemented with lysine and if the diet is not deficient in other amino acids. Corn-soybean meal diets that are reduced more than two percent in protein may become deficient in the amino acid tryptophan. Oats contains more lysine and tryptophan but less energy than corn. However, dietary levels of 20 to 30% oats have generally not affected pig performance. The objectives of this experiment were to evaluate the protein and lysine needs of growing-finishing pigs and to determine the value of oats as an amino acid source in low protein diets containing 20% oats as a replacement for corn

    The Effect of Protein Level and Amino Acid Supplementation of Sunflower Meal Diets for Young Pigs

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    Dietary protein recommendations for pigs were developed using corn-soybean meal diets. Diets formulated to contain less protein than recommended will result in reduced performance because of a deficiency of amino acid(s). However, more recent research suggests that pig performance can be maintained when feeding diets containing a substantially reduced protein content if limiting amino acids are supplemented to meet dietary requirements. Previous research at South Dakota State University has identified lysine, tryptophan and threonine as deficient amino acids in a 12% protein, corn-sunflower meal diet. The objectives of the trial reported herein were to study the effect of protein level (12, 15, 18 and 21%) in corn-sunflower meal diets containing all essential amino acids in excess of National Research Council recommendations and to determine the effect of glutamic acid supplementation to a low protein (12%) diet as a non-essential amino acid nitrogen source

    Barley Diets for Growing-Finishing Pigs

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    Barley is an important feed ingredient that may be used as an alternative for corn in swine diets. It is higher in protein and the amino acid lysine than is corn. But, it also contains less energy than corn and thus diets based on barley as the grain source are less efficient than corn based diets. It has also been suggested that hogs fed barley diets do not yield ~s well as those fed corn diets. The objectives of this experiment were to determine the effect of lysine and fat supplementation to barley based diets and to compare these diets with corn based diets. A further objective was to determine the effect of barley diets on carcass characteristics and dressing percentage

    Effect of Threonine Supplementation of a Low Protein, Corn-Sunflower Meal Diet for Young Growing Pigs

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    Of the ten essential amino acids required by swine, lysine, tryptophan and threonine have been reported by many researchers as being the first three limiting amino acids in cereal based swine diets. Research reported in the 1984 Swine Field Day Proceedings suggested supplementation of threonine to an amino acid fortified, low protein, corn-sunflower meal diet improves weanling pig performance. This trial was conducted as a continuation of the study of the effects of threonine supplementation an amino acid fortified, low protein, corn-sunflower meal diet and to estimate the dietary requirement of threonine of young growing pigs

    Effect of Tryptophan Supplementation of a Low Protein, Corn-Sunflower Meal Diet for Young Growing Pigs

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    Research conducted at South Dakota State University and reported in the 1983 and 1984 Swine Field Day Proceedings, indicated that the amino acid tryptophan is limiting in a lysine supplemented, 12% protein, corn-sunflower meal diet fed to young weaned pigs. This trial was conducted to further study the effects of tryptophan supplementation of an amino acid fortified, 12% protein, corn-sunflower meal diet and to estimate the dietary tryptophan requirement of the young weaned pig fed that diet
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