Finite element analysis of interlocking mortarless hollow block masonry prism

Interlocking mortarless masonry system has been developed as an alternative system for the conventional bonded masonry. This paper covers the analysis of interlocking mortarless hollow concrete block system subjected to axial compression loads using FEM. An incremental-iterative finite element code is written to analyze the masonry system till failure. The stress-strain relation obtained from test is employed and equivalent uniaxial strain concept is used to account for the material nonlinearity in the compression stress field. The developed program is also capable of simulating the nonlinear progressive contact behaviour (seating effect) of dry joint taking into account the block bed imperfection. The comparison shows a good agreement between the developed FE program and the experimental test results.     

CFD insight of the flow dynamics in a novel swirler for gas turbine combustors

We describe the flow dynamics inside a novel swirler conceptualized for gas turbine combustors. The supreme advantage in this swirler is the ability to vary the swirl number for the same value of Reynolds number. The significance of such advantage against contemporary configurations, which have constant swirl number, is quite evident at low turbine operating loads. The novel geometry and flow pattern are described in details in the present work. The results of four numerical simulations are presented and discussed to study the central recirculation zone, turbulence intensity, and pressure drop at different swirl numbers. The new concept is deemed to enhance the combustion efficiency because of its ability to adjust the swirl number according to the turbine operating load. The current study reports preliminary results which verify the concept behind the proposed swirler. However, intensive numerical and experimental studies are necessary to be carried out in order to characterize the flow dynamics produced by the novel swirler and its impact on the combustion process.     

Novel single-phase and gram-scale synthesis of thiol-uncapped stable colloidal gold nanoparticles

Here we describe a new chemical route for obtaining nanometer-sized gold(0) particles with a narrow size distribution and a band gap of 1.45 eV. The synthetic method is based on the reduction of AuBr3 with t-BuOLi activated LiH in dioxane. The single-phase process developed allows the production of large quantities of stable thiol-uncapped gold(0) nanoparticles. These clusters were further used for the production of monodisperse Au nanoparticles with controlled surface properties through ligand exchange with 1-dodecanethiol or 1-decylamine.     

Development of finite element computer code for thermal analysis of roller compacted concrete dams

Thermal analysis of roller compacted concrete (RCC) dams plays an important role in their design and construction. This paper deals with the development of a finite element based computer code for the determination of temperatures within the dam body. The finite element code is then applied to the real full-scale problem to determine the impact of the placement schedule on the thermal response of roller compacted concrete dam. Based on the results obtained, it could be concluded that for a given roller compacted concrete dam, changing the placing schedule can optimize the locations of maximum temperature zones.     

Optimal and quasi‐optimal energy‐efficient storage sharing for opportunistic sensor networks

This paper investigates optimum distributed storage techniques for data preservation, and eventual dissemination, in opportunistic heterogeneous wireless sensor networks where data collection is intermittent and exhibits spatio‐temporal randomness. The proposed techniques involve optimally sharing the sensor nodes' storage and properly handling the storage traffic such that the buffering capacity of the network approaches its total storage capacity with minimum energy. The paper develops an integer linear programming (ILP) model, analyses the emergence of storage traffic in the network, provides performance bounds, assesses performance sensitivities and develops quasi‐optimal decentralized heuristics that can reasonably handle the problem in a practical implementation. These include the Closest Availability (CA) and Storage Gradient (SG) heuristics whose performance is shown to be within only 10% and 6% of the dynamic optimum allocation, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

RHO1 (YlRHO1) is a non-essential gene in Yarrowia lipolytica and complements rho1Delta lethality in Saccharomyces cerevisiae

The synthesis of beta-1,3-glucan, the structural component of the yeast cell wall that gives shape to the cell, occurs at the plasma membrane and is the result of the activity of at least a two-component complex. Fks1p is the catalytic subunit directly responsible for the synthesis of beta-1,3-glucan, whilst the second subunit, Rho1p, has a GTP-dependent regulatory role (Yamochi et al., 1994). RHO1 has been characterized in Saccharomyces cerevisiae (Yamochi et al., 1994), and in several other fungal species. In this work, we have used degenerate oligonucleotides derived from the conserved regions of Rho1ps to isolate the RHO1 gene of Yarrowia lipolytica. The gene isolated in this way, which we have named YlRHO1, encodes a 204 amino acid protein that shows a high degree of homology with other Rho1ps. However, unlike S. cerevisiae, the ylrho1Delta disruptant strain in Y. lipolytica is viable, although it exhibits an increased sensitivity to Calcofluor white and Congo red. Also, YlRHO1 complements rho1 lethality in S. cerevisiae at both 28 degrees C and 37 degrees C. The complete sequence of YlRHO1 can be obtained from GenBank under Accession No. AF279915.     

Characterization of a disulphide-bound Pir-cell wall protein (Pir-CWP) of Yarrowia lipolytica

In this work we have studied the disulphide-bound group of cell wall mannoproteins of Yarrowia lipolytica and Candida albicans. In the case of Y. lipolytica, SDS-PAGE analysis of the beta-mercaptoethanol-extracted material from the purified cell walls of the yeast form, showed the presence of a main polypeptide of 45 kDa and some minor bands in the 100-200 kDa range. This pattern of bands is similar to that obtained in identical extracts in Saccharomyces cerevisiae (Moukadiri et al., 1999), and besides, all these bands cross-react with an antibody raised against beta-mercaptoethanol-extracted material from the purified cell walls of S. cerevisiae, suggesting that the 45 kDa band could be the homologue of Pir4 of S. cerevisiae in Y. lipolytica. To confirm this possibility, the amino-terminal sequences of two internal regions of the 45 kDa protein were determined, and degenerate oligonucleotides were used to clone the gene. The gene isolated in this way codes a 286 amino acid polypeptide that shows homology with the Pir family of proteins of S. cerevisiae (Russo et al., 1992; Toh-e et al., 1993), accordingly we have named this gene YlPIR1. Disruption of YlPIR1 led to a slight increase in the resistance of the cells to calcofluor white, Congo red and zymolyase, but did not cause changes in cell morphology, growth rate or morphological transition.     

On the performance of multi‐hop wireless relay networks

User cooperation has evolved as a popular coding technique in wireless relay networks (WRNs). Using the neighboring nodes as relays to establish a communication between a source and a destination achieves an increase of the diversity order. The relay nodes can be seen as a distributed multi‐antenna system, which can be exploited for transmit diversity by using distributed space–time block coding (STBC). In this paper, we investigate the bit error rate (BER) of multi‐hop WRNs employing distributed STBC at the relay nodes. We develop the general model of WRNs using distributed STBC, and we derive the pairwise error probability and an approximation of the BER. We examine the impact of several parameters, such as distributed STBC at the relays, the number of relays, the distances between the nodes, and the channel state information available at the receivers, on the BER performance of the multi‐hop WRN. The obtained results provide guidelines about the expected error performance and the design of channel estimation for these networks. Copyright © 2011 John Wiley & Sons, Ltd.