A hybrid,finite element—finite difference approach to simplified large deflection analysis of structures

A new and considerably simplified solution technique for geometrically nonlinear problems is introduced. In contrast to the existing numerical methods, the present approach obtains an approximate large deflection pattern from the linear displacement vector by successively employing updated correction factors. Conservation of energy principle yields a general expression for these subsequent corrections. While the linear portion of the strain energy can be computed using finite element approach, evaluations of its nonlinear counterparts often require mathematical discretization techniques. The simple, self-correcting iterative procedure is unconditionally stable and its fast oscillatory convergence offers further computational efficiency. To illustrate the application of the proposed method and to assess its accuracy, moderately large deflections of beam, plate and flexible cable structures have been computed and compared with known analytical solutions. If required, the obtained results—which are acceptable for most design purposes—can be further improved.     

The case for extended nuclear reactor operation

Greenhouse gas emission is a mounting problem that threatens the future production of electricity from both coal and natural gas. In 2006, 70% of domestic electricity generation relied upon fossil fuels. Projections by the Energy Information Agency¹ show U.S. demand for electricity increasing 30% to 40% by 2030. Today nuclear power is the largest source of non-greenhouse-gas emitting energy generation and will be an important source of energy production in the future. This paper considers potential construction of new plants as well as the long-term prospects of existing nuclear power plants in the United States.     

Effect of target peak power density on the phase formation,microstructure evolution,and mechanical properties of Cr2AlC MAX-phase coatings

The applicability of Cr₂AlC MAX-phases as protective coatings in energy conversion or aerospace applications requires a dense, single-phase structure. Therefore, we study the effect of target power density and substrate bias on phase formation, microstructure evolution, and mechanical properties of Cr₂AlC coatings utilizing direct current (DCMS) and high-power pulsed magnetron sputtering (HPPMS). Generally, HPPMS results in coatings with superior density and hence larger elastic moduli compared to DCMS, indicating that ion bombardment by ionized film-forming species is beneficial. However, decreasing the substrate bias to ?200 V for DCMS and ?100 V for HPPMS favors the ion bombardment induced formation of the disordered (Cr,Al)₂C_x solid solution. It is evident that there is an optimum moderate ion energy for the formation of dense Cr₂AlC coatings. Too low energy results in the formation of under-dense coatings. Too high energy yields the formation of (Cr,Al)₂C_x in addition to Cr₂AlC.     

Coherent Infrared Lidar with Enhanced Optical Heterodyne Detection

Abstract

Enhanced operation of a coherent infrared differential absorption lidar was demonstrated in case when appropriately selected laser sources were used. Good agreement with experimental data supports the idea that, in the case of reinjecting the weak frequency shifted signal into the source laser cavity (autodyne arrangement), a model based on forced relaxation oscillations can describe the operation of the system.     

Antibodies directed against a yeast carboxyl-terminal peroxisomal targeting signal specifically recognize peroxisomal proteins from various yeasts.

The carboxyl-terminal tripeptide Ala-Lys-Ile is essential for targeting Candida tropicalis trifunctional enzyme (hydratase-dehydrogenase-epimerase) to peroxisomes of both Candida albicans and Saccharomyces cerevisiae (Aitchison,J.D., Murray, W.W. and Rachubinski, R. A. (1991).J. Biol. Chem. 266, 23197-23203). We investigated the possibility that this tripeptide may act as a general peroxisomal targeting signal (PTS) for other proteins in the yeasts C. tropicalis, C. albicans, Yarrowia lipolytica and S. cerevisiae, and in rat liver. Anti-AKI antibodies raised against the carboxyl-terminal 12 amino acids of trifunctional enzyme were used to search for this PTS in proteins of these yeasts and of rat liver. The anti-AKI antibodies reacted exclusively with multiple peroxisomal proteins from the yeasts C. tropicalis, C. albicans and Y. lipolytica. There was a weak reaction of the antibodies with one peroxisomal protein from S. cerevisiae and no reaction with peroxisomal proteins from rat liver. Antibodies directed against a synthetic peptide containing a carboxyl-terminal Ser-Lys-Leu PTS (Gould, S. J., Krisans, S., Keller, G.-A. and Subramani, S. (1990). J. Cell Biol. 110,27-34) reacted with multiple peroxisomal proteins of rat liver and with peroxisomal proteins of yeast distinct from those identified with anti-AKI antibodies. These results provide evidence that several peroxisomal proteins of different yeasts contain a PTS antigenically similar to that of C. tropicalis trifunctional enzyme and that this signal is absent from peroxisomal proteins from at least one mammalian system, rat liver.     

Mixed line rate virtual topology design considering nonlinear interferences between amplitude and phase modulated channels

In the last years, the migration from 10 to 40/100 Gbps networks has been proposed as a solution to increase the capacity of transparent optical networks. Initially, the replacement of 10 Gbps legacy equipment was considered. Nowadays, some works point out that the deployment of mixed line rate (MLR) networks, where 10 Gbps and higher bit rate Gbps channels share the same fiber, could be more cost effective than the total replacement of 10 Gbps systems. In this paper, we investigate the planning of 10/40 Gbps MLR networks using the ITU 50 GHz grid, considering nonlinear interferences between 10 and 40 Gbps channels, which degrade the quality of transmission. This approach is novel in the literature. In addition, we conduct a set of tests normalizing the length of fiber links, to observe the trends in MLR planning for different network sizes.     

Semicarbazide in baby food: a European survey

The concentration of semicarbazide (SEM) in baby food packed in glass jars with lids sealed with plastic gaskets was determined in more than 100 samples, produced in 11 European countries, and purchased at local supermarkets in 14 countries. The method used for the analyses has been recently validated in a collaborative study. A correlation between the measured SEM concentration and the type of food (fruit, vegetables, meat and combinations of those) was found. The lowest values of SEM were found in samples containing only fruit with a mean concentration of 5.5±3.8 μg/kg. Some brands were characterised by low levels of SEM regardless of the composition. The levels of SEM found were comparable for the different countries of production. Both, high and low semicarbazide levels were found among organic and conventional samples.     

消除葡萄糖效应提高酵母降糖速度的研究

葡萄糖阻遏效应是造成啤酒发酵缓慢的原因之一,利用葡萄糖结构类似物可以筛选出抗葡萄糖阻遏效应的菌株,从而提高酵母的发酵速度,常见的葡萄糖结构类似物有2-脱氧-D-葡萄糖和N-乙酰基-D-葡糖胺。本试验以降糖速度为发酵速度指标,利用固体培养以及液体发酵的方法来选择合适的葡萄糖结构类似物,并用紫外诱变法筛选出降糖速度快的突变菌株28号,通过遗传稳定性试验研究了所选菌株的稳定性。     

Semi-supervised learning for character recognition in historical archive documents

Training recognizers for handwritten characters is still a very time consuming task involving tremendous amounts of manual annotations by experts. In this paper we present semi-supervised labeling strategies that are able to considerably reduce the human effort. We propose two different methods to label and later recognize characters in collections of historical archive documents. The first one is based on clustering of different feature representations and the second one incorporates a simultaneous retrieval on different representations. Hence, both approaches are based on multi-view learning and later apply a voting procedure for reliably propagating annotations to unlabeled data. We evaluate our methods on the MNIST database of handwritten digits and introduce a realistic application in form of a database of handwritten historical weather reports. The experiments show that our method is able to significantly reduce the human effort that is required to build a character recognizer for the data collection considered while still achieving recognition rates that are close to a supervised classification experiment.