641 research outputs found

    A Holistic Approach to Log Data Analysis in High-Performance Computing Systems: The Case of IBM Blue Gene/Q

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    The complexity and cost of managing high-performance computing infrastructures are on the rise. Automating management and repair through predictive models to minimize human interventions is an attempt to increase system availability and contain these costs. Building predictive models that are accurate enough to be useful in automatic management cannot be based on restricted log data from subsystems but requires a holistic approach to data analysis from disparate sources. Here we provide a detailed multi-scale characterization study based on four datasets reporting power consumption, temperature, workload, and hardware/software events for an IBM Blue Gene/Q installation. We show that the system runs a rich parallel workload, with low correlation among its components in terms of temperature and power, but higher correlation in terms of events. As expected, power and temperature correlate strongly, while events display negative correlations with load and power. Power and workload show moderate correlations, and only at the scale of components. The aim of the study is a systematic, integrated characterization of the computing infrastructure and discovery of correlation sources and levels to serve as basis for future predictive modeling efforts.Comment: 12 pages, 7 Figure

    Joints of composite construction in marine structures

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    Imperial Users onl

    Radiation exposure from diagnostic nuclear medicine examinations in golestan province

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    Introduction: The aim of present study was to estimate effective dose from most common procedures performed in nuclear medicine departments of Golestan province. Methods: Data of nuclear medicine procedures performed in 2 nuclear medicine departments in Golestan province were collected during 4 years. Effective dose, collective effective dose and effective dose per examination were calculated using standard dosimetry tables. Results: Based on the data of this study, results of 10437 nuclear medicine procedures performed during 4 years have lead to 3.97 mSv as average effective dose per examination and 10.37 human-Sv as mean collective effective dose. It was also revealed that Tc-99m was the main source of effective dose (98.3%), bone scan was the most common procedure (25.9%) and cardiac scan (MIBI-rest) has the highest collective effective dose (33.5%) during 4 years. Conclusion: Beside the cardiac scan which was the most common nuclear medicine procedure and the main contributor of effective dose in patients, due to geographical condition of the northeast of Iran, bone scan was the highest performed nuclear medicine examination in the Golestan province

    Effect of thermal history on the properties of bentonite

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    PublishedJournal ArticleThis is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.© 2016, Springer-Verlag Berlin Heidelberg.The effect of thermal history on the properties of bentonite was studied through a number of experimental tests. The desired thermal history was created on samples of bentonite by keeping them at a fixed temperature (50, 100, 150, 200 and 250 °C) for a specific duration (3, 7, 14 and 30 days). Standard compaction, Atterberg limits, free swelling and swelling pressure tests were carried out on the samples on the dry side of optimum, optimum and wet side of optimum of the compaction curve with desired thermal history. In addition chemical tests were carried out on the flooding water at the end of the swelling test. The results showed that the changes in compaction characteristics were not considerable but the Atterberg limits, free swelling and swelling pressure of the soil were changed due to the thermal history in comparison with the soil without any thermal history. The magnitudes of free swelling and swelling pressure were dependent on the location of prepared sample on the compaction curve. In addition, the changes in Atteberg limits and swelling parameters (amount of free swelling and swelling pressure) were functions of magnitude of temperature and duration of time that the sample experienced the temperature in its temperature history. The effects of temperature and also duration of exposure of the soil to temperature was discussed with the aid of the Diffuse Double Layer (DDL) theory. It was found that the temperature may change the gradation of soil due to cementation of particles as a result of formation of some salts and oxides that help to paste the particles together and change the properties of the soil

    Nonunitary Gate Operations by Dissipation Engineering

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    Irreversible logic is at odds with unitary quantum evolution. Emulating such operations by classical measurements can result in disturbances and high resource demands. To overcome these limitations, we propose protocols that harness dissipation to realize the nonunitary evolution required for irreversible gate operations. Using additional excited states subject to decay, we engineer effective decay processes that perform the desired gate operations on the smallest stable Hilbert space. These operate deterministically and in an autonomous fashion, without the need for measurements. We exemplify our approach considering several classical logic operations, such as the OR, NOR, and XOR gates. Towards experimental realization, we discuss a possible implementation in quantum dots. Our study shows that irreversible logic operations can be efficiently performed on realistic quantum systems and that dissipation engineering is an essential tool for obtaining nonunitary evolutions. The proposed operations expand the quantum engineers' toolbox and have promising applications in NISQ algorithms and quantum machine learning

    Study on antibiotic residues in Rainbow trout (Oncorhynchus mykiss) in Tabriz market

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    Vast application of the antibiotic drugs in animals without due attention to withdrawal times necessitates quality control of food stuff in terms of antibiotics' residues. Antibiotic residues in food stuff cause bacterial resistance, allergic reactions, toxicity, carcinogenic effects and change of natural micro flora of intestine in consumers. So, the aim of the present study is detection of antibiotic residues and its contamination rate in cultured rainbow trout. Four-plate test is one of the microbiological methods of detecting antibiotic residues in food stuff, which is based on inhibition zone formation around the sample in four culture media with different pH and test bacteria. For this purpose, 45 samples from skin and meat of rainbow trout fish were obtained randomly from fish market of Tabriz city. After different phases of four-plate test, from a total of 180 skin samples, 13 cases (7.22%) and from a total of 180 meat samples, 18 cases (10%) were diagnosed to be contaminated to antibiotic residues. The results showed that contamination rate of two tissues, (meat and skin), have no significant difference (P>0.05), and the highest contamination to antibiotic residues were related to penicillin and macrolides groups (P<0.05)

    Residual stress measurement round robin on an electron beam welded joint between austenitic stainless steel 316L(N) and ferritic steel P91

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    This paper is a research output of DMW-Creep project which is part of a national UK programme through the RCUK Energy programme and India's Department of Atomic Energy. The research is focussed on understanding the characteristics of welded joints between austenitic stainless steel and ferritic steel that are widely used in many nuclear power generating plants and petrochemical industries as well as conventional coal and gas-fired power systems. The members of the DMW-Creep project have under- taken parallel round robin activities measuring the residual stresses generated by a dissimilar metal weld (DMW) between AISI 316L(N) austenitic stainless steel and P91 ferritic-martensitic steel. Electron beam (EB) welding was employed to produce a single bead weld on a plate specimen and an additional smoothing pass (known cosmetic pass) was then introduced using a defocused beam. The welding re- sidual stresses have been measured by five experimental methods including (I) neutron diffraction (ND), (II) X-Ray diffraction (XRD), (III) contour method (CM), (IV) incremental deep hole drilling (iDHD) and (V) incremental centre hole drilling (iCHD). The round robin measurements of weld residual stresses are compared in order to characterise surface and sub-surface residual stresses comprehensively

    Stabilization and Solidification of a Clay Soil Contaminated with MTBE

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    This is the author accepted manuscript. The final version is available from the American Society of Civil Engineers via the DOI in this record.This paper presents an investigation into stabilization and solidification of a clay soil contaminated with methyl butyl ether (MTBE) using two different agents (cement and a mixture of bentonite and cement) through a program of laboratory experiments. The samples were prepared in two stages. In the first stage, they were prepared with 20 and 30% cement, but in the second stage they were prepared with 20 and 30% mixtures of bentonite and cement (with ratios of bentonite to cement equal to 1∶11∶1 and 3∶13∶1). Unconfined compression tests (UCT) and leaching tests using a gas chromatography (GC) apparatus were conducted on the samples prepared in the described two stages at different curing times. The results show that by using cement, the strength of the soil is increased. The results of the leaching tests on contaminated soil show a major reduction in the concentration of MTBE. Adding cement to contaminated soil causes a reduction in the concentration of MTBE, but by increasing the curing time, the concentration of MTBE is increased. It is also indicated that using a combination of bentonite and cement leads to reductions in MTBE concentration, and the amount of reduction is decreased by increasing the curing time. A bentonite to cement ratio of 3∶13∶1 is more effective than 1∶11∶1 in reducing the concentration of MTBE

    An effective constitutive model for lime treated soils

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    This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this record.The effect of lime on the yield stress, and more generally the presence of structure in the soil, is usually not accounted for in the design of geotechnical structures. As a result the potential of lime treatment or of a structured soil has not been fully exploited. This paper presents a new formulation to account for the effect of structure on the mechanical behaviour for structured soils. A constitutive model is proposed in the framework of the Modified Cam Clay model to describe the behaviour of lime treated soils. The new formulation introduces a limited number of additional parameters, all of which have a physical meaning and can be obtained from an isotropic compression test. Due to similarity in behaviour of lime treated soils and naturally structured soils, the formulation can be applied to both types of soil. It is shown that the proposed model can successfully reproduce the main features of both structured soils such as maximum rate of dilation at softening and degradation at yield. The model can be applied for any structured material regardless of the origin of cementation

    Electrokinetic Remediation of a Soil Contaminated with Anthracene Using Different Surfactants

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    This is the author accepted manuscript. The final version is available from Mary Ann Liebert via the DOI in this recordElectrokinetic technique is one of the common methods that can be used for removal of organic contaminants in soil. There are some organic contaminants with low solubility in water. To improve the efficiency of remediation it is possible to use appropriate surfactants as flushing solution. In this work nonionic (Poloxamer 407 and Tween 80), anionic (sodium dodecyl sulfate [SDS]), and humic acid (HA) with solution of 0.1 M NaOH were selected for improving the remediation of a soil contaminated with anthracene. A solution of NaOH and surfactants were used as anolyte, but HA was mixed with contaminated soil. At the end of each test a number of soil samples were extracted from the middle of the soil at different distances from the anode, and removal of contaminant was measured by a high performance liquid chromatography apparatus. Results show the effectiveness of solution surfactants and NaOH in removal of anthracene was SDS > Tween 80 > Poloxamer 407. In addition, results indicate that effect of HA on remediation is less than SDS and more than nonionic surfactants
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