1,348 research outputs found
Transport on exploding percolation clusters
We propose a simple generalization of the explosive percolation process
[Achlioptas et al., Science 323, 1453 (2009)], and investigate its structural
and transport properties. In this model, at each step, a set of q unoccupied
bonds is randomly chosen. Each of these bonds is then associated with a weight
given by the product of the cluster sizes that they would potentially connect,
and only that bond among the q-set which has the smallest weight becomes
occupied. Our results indicate that, at criticality, all finite-size scaling
exponents for the spanning cluster, the conducting backbone, the cutting bonds,
and the global conductance of the system, change continuously and significantly
with q. Surprisingly, we also observe that systems with intermediate values of
q display the worst conductive performance. This is explained by the strong
inhibition of loops in the spanning cluster, resulting in a substantially
smaller associated conducting backbone.Comment: 4 pages, 4 figure
REDUCTION OF NITRIC OXIDE WITH CARBONACEOUS MATERIALS FROM PEAT
The direct NO reduction to produce N2 and CO2 using carbonaceous materials, chars and
activated carbons, was studied. Chars were prepared from peat by pyrolysis, at temperatures
ranging from 873 K to 1073 K. Activated carbons were prepared by the physical activation
of chars with steam, in a steel reactor, at 1073 K for 12 minutes, 25 minutes and 45
minutes. The kinetics of NO reduction using chars and activated carbons produced at
different experimental conditions were evaluated at different temperatures in the range
623-723 K. The gaseous products were essentially CO2 and N2 and the amount of CO
produced was negligible. The effect of the temperature on the kinetics of reduction was
also evaluated and the relationship between the rate constant and the temperature showed
an Arrhenius dependence. Activation energies of the NO reduction were in the range 6.75
to 7.97 kcal.mol-1 for the chars and in the range 8.14 to 9.52 kcal.mol-1 for the activated
carbons
Introduction of the Circular Economy to Expanded Polystyrene Household Waste: A Case Study From an Ecuadorian Plastic Manufacturer
[Abstract] Transition towards a more sustainable society is a complex task. The depletion of natural resources and waste generation cannot be sustained indefinitely, i.e. as waste increases, local landfills keep growing and land availability reduces. The introduction of circular economy in effective household solid waste management practices should be considered especially for third world countries, such as Ecuador. In this context, plastic recycling is an important step, particularly the case of expanded polystyrene containers that currently are single-use only and later end up in local landfills. This paper presents a methodology for recycling Expanded Polystyrene by means of a case study from an Ecuadorian Plastic Manufacturer. First, the manufacture of resin from post-consume EPS containers was demonstrated possible by the manufacturer. Second, results show that using 30% of post-consume resin in the mix produce satisfactory laboratory results and operational recycled containers.The authors would like to thank Marco Roche, Eng.; Technical Manager of Plásticos del Litoral S.A. (PLASTLIT) for its involvement and compromise in this project. This paper is supported by the National Secretary of Superior Education, Science, Technology and Innovation (SENESCYT) – INEDITA program, project “Characterization of urban household waste in Guayaquil for the classification of plastic and organic waste and reuse in local industry
Programa para a estimativa do custo e produção de energia eléctrica para uma residência
Este trabalho apresenta um programa de computador que permite determinar o custo e a produção de energia proporcionada por abastecimento pela empresa fornecedora de energia eléctrica e por instalações fotovoltaicas, eólicas e híbridas (fotovoltaicas e eólicas), em função da localização da instalação em território lusitano. Este programa leva em consideração a economia efectuada e o prazo de amortização do investimento. O programa foi realizado com a utilização das seguintes linguagens de programação: HTML, JavaScript e PHP. Pretende-se disponibilizar o uso deste programa através da Internet, para que a sua utilização possa ser alargada ao máximo número de pessoas possível.Fundação para a Ciência e a Tecnologia (FCT), financiadora com fundos FEDER e OE do Projecto POCTI/ESE/48242/2002
The role of environmental stressors and genetic information on the antimicrobial tolerance of Ralstonia pickettii
info:eu-repo/semantics/draf
STUDIES OF SIMULATIONS OF TWO-PHASE WATER-AIR FLOWS USING ANSYS CFX.
Normally in all simulations of flows in computational fluid dynamics, CFD, it is common to use characteristic planes to visualize the profiles of the parameters of interest, mainly in 3D simulations.
The present work proposes a standard form of visualization that shows, mainly in two-phase flows, in a more realistic way, the dynamics of the development of the phase flow. This visualization is present within the CFX program in the post-processing module, in the option of representing volumes using sub option, isovolumes. Through this representation, the program highlights the volumes of the finite element mesh corresponding to the selected values of the parameter to be analyzed such as pressure, velocity, volumetric fraction, etc.
By means of the volume-isovolume representation, a well representative effect of the current flow pattern is obtained, especially when the volumetric fraction of the air or the gas phase of the flow is emphasized.
This form of visualization is being applied to the study of inclined two-phase flows, which will be tested in a new experiment currently under construction at the Laboratory of Experimental Thermal-Hydraulics – LTE of the Institute of Nuclear Engineering - IEN in Rio de Janeiro
Fast Matrix Multiplication via Compiler-only Layered Data Reorganization and Intrinsic Lowering
The resurgence of machine learning has increased the demand for
high-performance basic linear algebra subroutines (BLAS), which have long
depended on libraries to achieve peak performance on commodity hardware.
High-performance BLAS implementations rely on a layered approach that consists
of tiling and packing layers, for data (re)organization, and micro kernels that
perform the actual computations. The creation of high-performance micro kernels
requires significant development effort to write tailored assembly code for
each architecture. This hand optimization task is complicated by the recent
introduction of matrix engines by IBM's POWER10 MMA, Intel AMX, and Arm ME to
deliver high-performance matrix operations. This paper presents a compiler-only
alternative to the use of high-performance libraries by incorporating, to the
best of our knowledge and for the first time, the automatic generation of the
layered approach into LLVM, a production compiler. Modular design of the
algorithm, such as the use of LLVM's matrix-multiply intrinsic for a clear
interface between the tiling and packing layers and the micro kernel, makes it
easy to retarget the code generation to multiple accelerators. The use of
intrinsics enables a comprehensive performance study. In processors without
hardware matrix engines, the tiling and packing delivers performance up to 22x
(Intel), for small matrices, and more than 6x (POWER9), for large matrices,
faster than PLuTo, a widely used polyhedral optimizer. The performance also
approaches high-performance libraries and is only 34% slower than OpenBLAS and
on-par with Eigen for large matrices. With MMA in POWER10 this solution is, for
large matrices, over 2.6x faster than the vector-extension solution, matches
Eigen performance, and achieves up to 96% of BLAS peak performance
Circular Economy of Expanded Polystyrene Container Production: Environmental Benefits of Household Waste Recycling Considering Renewable Energies
[Abstract] Plastic industry is ubiquitous worldwide, and the generation of “plastic waste” has been steadily increasing to the point of being considered a high impact pollutant. The expanded polystyrene (EPS) plastic industry aware of the issue is interested on trying recycling post-consumer material. Through a recent study made in an alliance between the private sector and the academy, the feasibility of the EPS “mechanical” recycling was proven; therefore, a possible solution through a circular economy model. The aim of the present paper was to investigate the potential environmental impacts avoided by the circular economy scenario previously developed, through a life cycle assessment (LCA) performed for the city of Guayaquil, where 64% of all the plastic manufacturing industries in the country are located. The entire life cycle of 1.00 kg of 5 × 5 inch. food containers were assessed from the production stage until its end-of-life stage: focusing on three different valorization paths, circular economy closed-loop (container-to-container) proposal with electricity share of 2019 and another with the 2027 future one, and traditional linear economy (container-to-landfill). Results showed that the scenario C that considers the recycling of post-consumer EPS waste and the electricity share proposed for 2027 have lower impacts in 14 out of 16 categories, in specific for the Land use (−31%), Ozone Depletion (−28%), Acidification (−24%) and Terrestrial and Marine Eutrophication (−21%). These results strongly suggest that the recycling of these kind of plastic waste could benefit the environment greatly
Evolutionary plasticity determination by orthologous groups distribution
<p>Abstract</p> <p>Background</p> <p>Genetic plasticity may be understood as the ability of a functional gene network to tolerate alterations in its components or structure. Usually, the studies involving gene modifications in the course of the evolution are concerned to nucleotide sequence alterations in closely related species. However, the analysis of large scale data about the distribution of gene families in non-exclusively closely related species can provide insights on how plastic or how conserved a given gene family is. Here, we analyze the abundance and diversity of all Eukaryotic Clusters of Orthologous Groups (KOG) present in STRING database, resulting in a total of 4,850 KOGs. This dataset comprises 481,421 proteins distributed among 55 eukaryotes.</p> <p>Results</p> <p>We propose an index to evaluate the evolutionary plasticity and conservation of an orthologous group based on its abundance and diversity across eukaryotes. To further KOG plasticity analysis, we estimate the evolutionary distance average among all proteins which take part in the same orthologous group. As a result, we found a strong correlation between the evolutionary distance average and the proposed evolutionary plasticity index. Additionally, we found low evolutionary plasticity in <it>Saccharomyces cerevisiae </it>genes associated with inviability and <it>Mus musculus </it>genes associated with early lethality. At last, we plot the evolutionary plasticity value in different gene networks from yeast and humans. As a result, it was possible to discriminate among higher and lower plastic areas of the gene networks analyzed.</p> <p>Conclusions</p> <p>The distribution of gene families brings valuable information on evolutionary plasticity which might be related with genetic plasticity. Accordingly, it is possible to discriminate among conserved and plastic orthologous groups by evaluating their abundance and diversity across eukaryotes.</p> <p>Reviewers</p> <p>This article was reviewed by Prof Manyuan Long, Hiroyuki Toh, and Sebastien Halary.</p
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