Ridged surface for reducing eddy-current losses in ferromagnetic shielding

Because of the increasing demand for electric power, devices operating at higher and higher currents have been developed and are being produced. These machines are placed in a closed metal enclosure that provide also shielding of the electromagnetic field. Two novel methods to reduce Joule-heat losses in shielding are described. These methods are based on making the surface of the ferromagnetic shielding material corrugated or ridged, thus increasing the conductive area for the eddy currents. The results were obtained from 1D and 2D finite element models of the new and conventional types of shielding, considering also the non-linear magnetization curve of the material used. It can be seen that the ridging can be a beneficial alternative of coating with high-conductivity material, e.g., copper, in reduction of eddy current losses.     

Decomposition of Nitrous Oxide over Fe-Ferrierites. Effect of High-Temperature Pretreatment on the Formation of Deposited Oxygen

The dehydration of Fe-ferrierites doubled the decomposition of N₂O at 200 ° C and corresponding deposition of oxygen. The rehydration resulted in a reversible process. Samples with iron located predominantly in cationic positions (Fe/Al 0.05–0.25) exhibited the O _dep /Fe ratio of ca. 0.5 and 1 after pretreatment at 450 and 700 °C, respectively.     

How expressive is stratified aggregation?

We present results on the expressive power of various deductive database languages extended with stratified aggregation. We show that (1) Datalog extended with stratified aggregation cannot express a query to count the number of paths between every pair of nodes in an acyclic graph, (2) Datalog extended with stratified aggregation and arithmetic on integers (the + operator) can express allcomputable queries on ordered domains, and (3) Datalog extended with stratified aggregation and generic function symbols can express allcomputable queries (on ordered or unordered domains). Note that without stratified aggregation, the above extensions of Datalog cannot express all computable queries. We show that replacing stratified aggregation by stratified negation preserves expressiveness. We identify subclasses of the above languages that are complete (can express all, and only the, computable queries).     

Nonlinear Analysis of Masonry Arches Strengthened with Composite Materials

The nonlinear behavior of masonry arches strengthened with externally bonded composite materials is investigated. A finite-element (FE) formulation that is specially tailored for the nonlinear analysis of the strengthened arch is developed. The FE formulation takes into account material nonlinearity of the masonry construction and high-order kinematic relations for the layered element. Implementation of the above concept in the FE framework reduces the general problem to a one-dimensional nonlinear formulation in polar coordinates with a closed-form representation of the elemental Jacobian matrix (tangent stiffness). A numerical study that examines the capabilities of the model and highlights various aspects of the nonlinear behavior of the strengthened masonry arch is presented. Emphasis is placed on the unique effects near irregular points and the nonlinear evolution of these effects through the loading process. A comparison with experimental results and a discussion of the correlating aspects and the ones that designate needs of further study are also presented.     

TRIM25 and DEAD-Box RNA Helicase DDX3X Cooperate to Regulate RIG-I-Mediated Antiviral Immunity

The cytoplasmic retinoic acid-inducible gene-I (RIG-I)-like receptors (RLRs) initiate interferon (IFN) production and antiviral gene expression in response to RNA virus infection. Consequently, RLR signalling is tightly regulated by both host and viral factors. Tripartite motif protein 25 (TRIM25) is an E3 ligase that ubiquitinates multiple substrates within the RLR signalling cascade, playing both ubiquitination-dependent and -independent roles in RIG-I-mediated IFN induction. However, additional regulatory roles are emerging. Here, we show a novel interaction between TRIM25 and another protein in the RLR pathway that is essential for type I IFN induction, DEAD-box helicase 3X (DDX3X). In vitro assays and knockdown studies reveal that TRIM25 ubiquitinates DDX3X at lysine 55 (K55) and that TRIM25 and DDX3X cooperatively enhance IFNB1 induction following RIG-I activation, but the latter is independent of TRIM25’s catalytic activity. Furthermore, we found that the influenza A virus non-structural protein 1 (NS1) disrupts the TRIM25:DDX3X interaction, abrogating both TRIM25-mediated ubiquitination of DDX3X and cooperative activation of the IFNB1 promoter. Thus, our results reveal a new interplay between two RLR-host proteins that cooperatively enhance IFN-β production. We also uncover a new and further mechanism by which influenza A virus NS1 suppresses host antiviral defence.     

B‐bar FEMs for anisotropic elasticity

Anisotropic elastic materials, such as the homogenized model of a fiber‐reinforced matrix, can display near rigidity under certain applied stress–the resulting strains are small compared with the strains that would occur for other stresses of comparable magnitude. The anisotropic material could be rigid under hydrostatic pressure if the material were incompressible, as in isotropic elasticity, but also for other stresses. Some commonly used finite elements are effective in dealing with incompressibility, but are ill‐equipped to handle materials that lock under non‐hydrostatic stress states (e.g., uniformly reduced serendipity and Q1/Q0 B‐bar hexahedra). The failure of the original B‐bar method is attributed to the assumption that the mode of deformation to be relieved is one of near incompressibility. The remedy proposed here is based on the spectral decomposition of the compliance matrix of the material. The spectrum can be interpreted to separate nearly‐rigid and flexible modes of stress and strain, which leads naturally to a generalized selective reduced integration. Furthermore, the spectral decomposition also enables a three‐field elasticity formulation that results in a B‐bar method that is effective for general anisotropic materials with an arbitrary nearly‐rigid mode of deformation.Copyright © 2014 John Wiley & Sons, Ltd.