Hydrogenative Cyclopropanation and Hydrogenative Metathesis

The unusual geminal hydrogenation of a propargyl alcohol derivative with [CpXRuCl] as the catalyst entails formation of pianostool ruthenium carbenes in the first place; these reactive intermediates can be intercepted with tethered alkenes to give either cyclopropanes or cyclic olefins as the result of a formal metathesis event. The course of the reaction is critically dependent on the substitution pattern of the alkene trap

A phased array-based method for damage detection and localization in thin plates

A method for damage localization based on the phased array idea has been developed. Four arrays oftransducers are used to perform a beam-forming procedure. Each array consists of nine transducersplaced along a line, which are able to excite and register elastic waves. The A0 Lamb wave mode hasbeen chosen for the localization method. The arrays are placed in such a way that the angulardifference between them is 458 and the rotation point is the middle transducer, which is common for allthe arrays. The idea has been tested on a square aluminium plate modeled by the Spectral Element Method. Two types of damage were considered, namely distributed damage, which was modeled asstiffness reduction, and cracks, modeled as separation of nodes between selected spectral elements.The plate is excited by a wave packet. The whole array system is placed in the middle of the plate.Each linear phased array in the system acts independently and produces maps of a scanned fieldbased on the beam-forming procedure. These maps are made of time signals (transferred to spacedomain) that represent the difference between the damaged plate signals and those from the intactplate. An algorithm was developed to join all four maps. The final map is modified by proposed signal processing algorithm to indicate the damaged area of the plate more precisely. The problem fordamage localization was investigated and exemplary maps confirming the effectiveness of theproposed system were obtained. It was also shown that the response of the introduced configurationremoves the ambiguity of damage localization normally present when a linear phased array is utilized.The investigation is based exclusively on numerical data

Optoelectronic Reservoir Computing

Reservoir computing is a recently introduced, highly efficient bio-inspired approach for processing time dependent data. The basic scheme of reservoir computing consists of a non linear recurrent dynamical system coupled to a single input layer and a single output layer. Within these constraints many implementations are possible. Here we report an opto-electronic implementation of reservoir computing based on a recently proposed architecture consisting of a single non linear node and a delay line. Our implementation is sufficiently fast for real time information processing. We illustrate its performance on tasks of practical importance such as nonlinear channel equalization and speech recognition, and obtain results comparable to state of the art digital implementations.Comment: Contains main paper and two Supplementary Material

Alkyne gem‐Hydrogenation: Formation of Pianostool Ruthenium Carbene Complexes and Analysis of Their Chemical Character

Parahydrogen (p‐H2) induced polarization (PHIP) NMR spectroscopy showed that [CpXRu] complexes with greatly different electronic properties invariably engage propargyl alcohol derivatives into gem‐hydrogenation with formation of pianostool ruthenium carbenes; in so doing, less electron rich CpX rings lower the barriers, stabilize the resulting complexes and hence provide opportunities for harnessing genuine carbene reactivity. The chemical character of the resulting ruthenium complexes was studied by DFT‐assisted analysis of the chemical shift tensors determined by solid‐state 13C NMR spectroscopy. The combined experimental and computational data draw the portrait of a family of ruthenium carbenes that amalgamate purely electrophilic behavior with characteristics more befitting metathesis‐active Grubbs‐type catalysts

Cultivo e uso de abóboras ornamentais.

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Zeros of Rydberg-Rydberg Foster Interactions

Rydberg states of atoms are of great current interest for quantum manipulation of mesoscopic samples of atoms. Long-range Rydberg-Rydberg interactions can inhibit multiple excitations of atoms under the appropriate conditions. These interactions are strongest when resonant collisional processes give rise to long-range C_3/R^3 interactions. We show in this paper that even under resonant conditions C_3 often vanishes so that care is required to realize full dipole blockade in micron-sized atom samples.Comment: 10 pages, 4 figures, submitted to J. Phys.

Desempenho de cultivares de tomateiro em diferentes ambientes de cultivo e sistema ecológico de produção.

O tomate é uma hortaliça de grande importância na mesa dos brasileiros, sendo que frutos produzidos de forma ecológica são preferidos e mais saudáveis. Para a produção exitosa de tomate neste sistema é necessária a utilização de cultivares adaptadas, dando-se preferência por aquelas de polinização aberta. A utilização de ambiente protegido tem viabilizado o cultivo do tomateiro em muitas regiões, com possibilidade de estender o período produtivo. O objetivo deste trabalho foi avaliar a produtividade e a duração do ciclo de duas cultivares de tomateiro produzidas a campo e em ambiente protegido em sistema de produção de base ecológica. O experimento foi realizado na Estação Experimental Cascata (Embrapa Clima Temperado), Pelotas, Rio Grande do Sul. Foram avaliados dois genótipos ?Rose de Berne? e ?Maçã?. O controle de insetos e doenças foi baseado na legislação brasileira de orgânicos. Após cada colheita, os frutos foram pesados e classificados, e ao final do período experimental foi determinada a produção de frutos por planta, número e massa média de frutos, e duração total do ciclo. ?Maçã? produziu mais frutos que ?Rose de Berne? por ser do tipo cereja, porém a produtividade das duas não diferiu entre si nem entre ambientes, mantendo em média 6,5 kg m-2. O descarte foi maior para ?Rose de Berne?. A massa média dos frutos a campo foi maior que na estufa. O ciclo de cultivo no ambiente protegido foi de 126 dias para ambas cultivares, sendo que a campo, ?Maçã? teve ciclo de apenas 109 dias e ?Rose de Berne? de 130 dias. A produtividade de ambas cultivares e ambientes foi satisfatória. O ambiente protegido não diferiu em produtividade com o campo, porém permitiu prolongar o ciclo de produção da cultivar ?Maçã?. Perdas podem ser reduzidas se forem realizadas colheitas mais frequentes