Enhanced hydrothermal resistance of Y-TZP ceramics through colloidal processing

Two commercial zirconia powders with 3mol% of yttria (TZ3YE and TZ3YS, labeled as ZE and ZS, respectively) supplied by Tosoh (Japan) were used for this study. Maximum colloidal stability for ZE was achieved by dispersing the powders in a mixture of water/ethanol of 90:10 (wt/wt) using a sonication probe. The rheological behavior of the suspensions was optimized in terms of solids content ranging from 20 to 33vol% and sonication time (06min), the best results being obtained after 2min. ZS samples were prepared to a solids loading of 30vol% in water dispersing with 2min-sonication. Samples obtained by slip casting in plaster molds were used for dynamic sintering studies, and fully dense and nanostructured specimens were obtained at temperatures of 1300 degrees C1350 degrees C (ZE samples) and 1400 degrees C per 2h (ZS samples). The Hardness (H) and Young's Modulus (E) properties of the specimens were studied by nanoindentation technique giving 17 and 250GPa mean values for H and E, respectively. The specimens were then forced to a low-temperature degradation (LTD) treatment at 130 degrees C for 240h in steps of 60h. Raman spectroscopy and nanoindentation results of hydrothermally treated samples showed the absence of transformation from tetragonal to monoclinic phase until 180h whereas the mechanical properties maintained constant even at the sample surface. After 240h of LTD, the monoclinic phase was detected on all specimens by Raman peaks centered at 180, 191, and 383cm1. The nanoindentation study revealed an important loss of mechanical features reaching 10 and 175GPa for H and E, respectively. In the case of the ZS specimens, no monoclinic phase is detected after 240h of LTD treatment and no decay of E or H is detected. The free defect microstructure reached for the ZS specimen revealed a higher hydrothermal resistance so that it is concluded that the excellent behavior against thermal degradation is possible due to the large uniformity obtained by colloidal processing rather than the particle size of the starting powders.This work has been supported by Spanish Ministry of Science and Innovation (Projects MAT2009-14144-C03-02, MAT2009-14369-C02-01, and MAT2008-03398). Authors thank Prof. M. Anglada for helpful comments and discussion. R Moreno thanks the Universidad Politecnica de Valencia for the concession of a grant in the frame of its Program of Support to R+D (PAID-02-11, R-1752). We also wish to acknowledge Rut Benavente for her excellent technical support.Rayón Encinas, E.; Moreno, R.; Alcazar, C.; Salvador Moya, MD.; Manjón Herrera, FJ.; Jimenez-Pique, E.; Llanes, L. (2013). Enhanced hydrothermal resistance of Y-TZP ceramics through colloidal processing. 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Risk governance in organizations

Dieses Buch dokumentiert 10 Jahre Risk-Governance-Forschung an der Universität Siegen. In 50 Beiträgen reflektieren Forscher und Praktiker Risk Governance vor dem Hintergrund ihrer eigenen Forschungen und/oder Erfahrungen und geben jeweils einen Entwicklungsimpuls für die Zukunft der Risk Governance. Das Buch zeigt die große Bandbreite und Tiefe des Forschungsgebietes auf und diskutiert Grundannahmen, Implementierungsfragen, die Rolle der Risk Governance als Transformationsmotor, ihre Wirkung in den verschiedenen betrieblichen Funktionen, Entwicklungsperspektiven und den Beitrag der Risk Governance zu einer nachhaltigen Ausrichtung von Unternehmen.This book documents 10 years of risk governance research at the University of Siegen. In 50 contributions, researchers and practitioners reflect on risk governance against the background of their own research and/or experience and provide a development impetus for the future of risk governance. The book shows the wide range and depth of the research field and discusses basic assumptions, implementation issues, the role of risk governance as transformation engine, its impact in the various operational functions, development perspectives, and the contribution of risk governance to a sustainable orientation of companies

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

Endophytes vs tree pathogens and pests: can they be used as biological control agents to improve tree health?

Like all other plants, trees are vulnerable to attack by a multitude of pests and pathogens. Current control measures for many of these diseases are limited and relatively ineffective. Several methods, including the use of conventional synthetic agro-chemicals, are employed to reduce the impact of pests and diseases. However, because of mounting concerns about adverse effects on the environment and a variety of economic reasons, this limited management of tree diseases by chemical methods is losing ground. The use of biological control, as a more environmentally friendly alternative, is becoming increasingly popular in plant protection. This can include the deployment of soil inoculants and foliar sprays, but the increased knowledge of microbial ecology in the phytosphere, in particular phylloplane microbes and endophytes, has stimulated new thinking for biocontrol approaches. Endophytes are microbes that live within plant tissues. As such, they hold potential as biocontrol agents against plant diseases because they are able to colonize the same ecological niche favoured by many invading pathogens. However, the development and exploitation of endophytes as biocontrol agents will have to overcome numerous challenges. The optimization and improvement of strategies employed in endophyte research can contribute towards discovering effective and competent biocontrol agents. The impact of environment and plant genotype on selecting potentially beneficial and exploitable endophytes for biocontrol is poorly understood. How endophytes synergise or antagonise one another is also an important factor. This review focusses on recent research addressing the biocontrol of plant diseases and pests using endophytic fungi and bacteria, alongside the challenges and limitations encountered and how these can be overcome. We frame this review in the context of tree pests and diseases, since trees are arguably the most difficult plant species to study, work on and manage, yet they represent one of the most important organisms on Earth

Practical Issues Relating to Tank Volume Determination

Issues relating to each element in the determination of a tank¿s contents are examined: level/density measurement, calibration, and its reverification. Systematic errors associated with dip tube pressures that are measured to derive level/density are investigated, experimentally. The conversion from these pressures to level/density is then addressed, and the simplest form is found to be adequate. A revised regression model is proposed to obtain a calibration from biased calibration data from one or more calibration runs. Severely biased calibration data can be eliminated, reducing the calibration error due to biases to a minimum. It is shown that a more accurate representation can be obtained using cubic splines. Finally, reverification issues are addressed by proposing a new continuous fill approach.JRC.H.2-Climate chang

The effectiveness of sampling plans based on both item-by-item tests and the stratum D-statistic

Nuclear fuel cycle facility declarations on nuclear material inventories and transfers are independently verified by the IAEA. These verification activities usually rely on a sampling plan that is designed to achieve a specified probability to detect falsification of operator reports. Currently, the IAEA’s sampling plans assume item-by-item tests in which the difference between the reported and the measured value of each item selected for verification is compared to a threshold. If a difference exceeds this threshold, then an “alarm” occurs, and the cause for the difference is further investigated. In the present paper we analyse sampling plans in which in addition to the usual item-by-item tests, a stratum difference statistic of the verified items is applied as a test statistic. The reason for considering the stratum difference statistic in addition to the item-by-item tests is that it is “better” at detecting bias defect falsifications than the item-by-item tests. Therefore, we investigate the effectiveness in terms of the achieved detection probability of sampling plans in which both tests are applied and analyse whether sample sizes could be reduced while still achieving the required detection probability

Evolving Statistical Methodologies for Safeguards

Statistical methodologies for safeguards were developed at an early stage of safeguards’ history and are rooted in the criteria-driven, facility-based approach which has long underpinned the International Atomic Energy Agency’s (IAEA) conclusions. While their principles and approaches remain generally valid in the framework of a State-level evaluation, their scope, previously restricted to material balance areas (MBA) within facilities, needs to be expanded to include the analysis of nuclear material flows, inventories and balances for a whole State, taking into account the increasing use of random inspection schemes in State-level approaches (SLA) and the implications for the statistical analysis of data collected according to these patterns. In addition to this undertaking, which poses a number of methodological challenges, new approaches are needed to address increasingly large and diversified data flows, to optimize the distribution of limited statistical analysis resources, to align them with the State-level technical objectives (TO) identified through the acquisition path analysis (APA) performed by the State evaluation groups (SEGs) and to develop probabilistic methods for the quantification of their targeted and achieved attainment. In addition, statistical evaluation results of State declared and verification data need to be consolidated and compared to information from other sources. Last but not least, considerable progress was made in the field of information technology (IT) and statistical methodologies since they were first applied to safeguards several decades ago. The current migration of the IAEA safeguards IT platform under the Modernization of Safeguards Information technology (MOSAIC) project has provided a unique opportunity to adapt and evolve methodologies and to integrate them into new software tools. This paper reviews the efforts undertaken in recent years by the Nuclear Fuel Cycle Information Analysis Section within the Safeguards Department Division of Information Management to review, upgrade, consolidate, and evolve safeguards statistical methodologies and describes the progress accomplished to date

Development Of An Enzymatic Assay For The Determination Of Cellulose Bioavailability In Municipal Solid Waste

As there is a constant need to assess the biodegradation potential of refuse disposed of in landfills, we have developed a method to evaluate the biodegradability of cellulosic compounds (cellulose and hemicellulose) in municipal solid waste. This test is based on the quantification of monosaccharids released after the hydrolysis of solid waste samples with an optimised enzyme preparation containing commercially available cellulases and hemicellulases. We show that the amounts of monosaccharids could be related to the biodegradability of the cellulosic material contained in the samples. This enzymatic cellulose degradation test was assayed on 26 samples originating from two Belgian landfills and collected at different depths. As results correlated well with those obtained with a classical biochemical methane potential assay, this new and rapid test is sufficiently reliable to evaluate cellulose bioavailability in waste samples.Confinement de centres d'enfouissement technique à l'aide de barrières argileuse