APEnet+: high bandwidth 3D torus direct network for petaflops scale commodity clusters

We describe herein the APElink+ board, a PCIe interconnect adapter featuring the latest advances in wire speed and interface technology plus hardware support for a RDMA programming model and experimental acceleration of GPU networking; this design allows us to build a low latency, high bandwidth PC cluster, the APEnet+ network, the new generation of our cost-effective, tens-of-thousands-scalable cluster network architecture. Some test results and characterization of data transmission of a complete testbench, based on a commercial development card mounting an Altera FPGA, are provided.Comment: 6 pages, 7 figures, proceeding of CHEP 2010, Taiwan, October 18-2

High-speed data transfer with FPGAs and QSFP+ modules

We present test results and characterization of a data transmission system based on a last generation FPGA and a commercial QSFP+ (Quad Small Form Pluggable +) module. QSFP+ standard defines a hot-pluggable transceiver available in copper or optical cable assemblies for an aggregated bandwidth of up to 40 Gbps. We implemented a complete testbench based on a commercial development card mounting an Altera Stratix IV FPGA with 24 serial transceivers at 8.5 Gbps, together with a custom mezzanine hosting three QSFP+ modules. We present test results and signal integrity measurements up to an aggregated bandwidth of 12 Gbps.Comment: 5 pages, 3 figures, Published on JINST Journal of Instrumentation proceedings of Topical Workshop on Electronics for Particle Physics 2010, 20-24 September 2010, Aachen, Germany(R Ammendola et al 2010 JINST 5 C12019

AERATION AND MIXING BEHAVIOURS OF BINARY MIXTURES OF NANO-SIZED POWDERS UNDER SOUND VIBRATION

The aeration behaviour of three different nano-sized powders, Al2O3, Fe2O3 and CuO, fluidized under the application of acoustic fields of different intensities (125-150 dB) and frequencies (50-300 Hz) has been characterized. The characterization of the fluidization of binary mixtures of Al2O3 and Fe2O3 has been also investigated under the application of acoustic fields of 120 Hz and of two different intensities, 130 and 135 dB, and varying the relative amount of two powders from 17 to 50 %wt of Fe2O3. The addition of Fe2O3 has a beneficial effect on fluidization quality of Al2O3 even for the lowest amount of Fe2O3. Under the effect of sound, mixing between Al2O3 and CuO nanopowders has been also quantitatively characterized by the Scanning Electron Microscopy with X-ray microanalysis (SEM/EDS) analysis of captured samples. Mixing between aggregates of the two powders takes only few minutes. However, mixing also occurs inside aggregates but this process requires times of the order of 80-150 minutes, depending on the feeding order of two powders

APENet: LQCD clusters a la APE

Developed by the APE group, APENet is a new high speed, low latency, 3-dimensional interconnect architecture optimized for PC clusters running LQCD-like numerical applications. The hardware implementation is based on a single PCI-X 133MHz network interface card hosting six indipendent bi-directional channels with a peak bandwidth of 676 MB/s each direction. We discuss preliminary benchmark results showing exciting performances similar or better than those found in high-end commercial network systems.Comment: Lattice2004(machines), 3 pages, 4 figure

ATTRITION OF BED MATERIALS AND FUEL PELLETS FOR FLUIDIZED BED GASIFICATION APPLICATION

This paper reports on a study of the attrition/fragmentation behavior of different bed materials and fuel pellets for application in fluidized bed gasification. Three different bed materials displaying catalytic activity, namely fresh and sintered dolomite and a Ni-alumina catalyst, were tested for their resistance to fragmentation and attrition in fluidized bed. The fresh dolomite displayed extensive particle breakage upon calcination and a large production of attrited fines during fluidized bed operation. The other two materials were much more resistant to attrition and appeared to be suitable for further long-term operation testing. The attrition/fragmentation resistance of three pelletized fuels, one based on wood and the other two on a mixture of wood and coal, was also characterized under both inert and gasification conditions. Pellet breakage by primary fragmentation upon devolatilization appeared to be rather limited for all fuels. On the contrary, attrition of carbon fines from the char particles during gasification was extensive, due to a gasification-assisted attrition mechanism

Status of the APENet project

Comment: 6 pages, 5 figures, poster presented at Lattice 2005 (Algorithms and Machines), Dublin, July 25-3

A comparison between interparticle forces estimated with direct powder shear testing and with sound assisted fluidization

Understanding the role of the interparticle forces in fluidization of cohesive powders is crucial for a proper application of fluidization to these type of powders. However, a direct measure of the interparticle interactions (IPFs) is challenging, mainly because cohesive particles cannot be fluidized under ordinary conditions. That is the reason why IPFs are typically measured using a rheological approach. The aim of this study is, therefore, to evaluate the IPFs of cohesive powders under actual fluidization conditions, by using an experimental and theoretical approach. In particular, a sound assisted fluidized bed apparatus was used to achieve a fluidization regime of the particles. Then, the cluster/subcluster model was applied to calculate IPFs, starting from the experimental data. The obtained IPFs were then compared to those evaluated by using a shear testing approach

Development of a Novel Concept of Solar Receiver/Thermal Energy Storage System Based on Compartmented Dense Gas Fluidized Beds

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Correction: Zinc is required to ensure the expression of flagella and the ability to form biofilms in Salmonella enterica sv Typhimurium

: Correction for 'Zinc is required to ensure the expression of flagella and the ability to form biofilms in Salmonella enterica sv Typhimurium' by Serena Ammendola et al., Metallomics, 2016, DOI: 10.1039/c6mt00108d