384 research outputs found

    Nanoscale austenite reversion through partitioning, segregation, and kinetic freezing: Example of a ductile 2 GPa Fe-Cr-C steel

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    Austenite reversion during tempering of a Fe-13.6Cr-0.44C (wt.%) martensite results in an ultrahigh strength ferritic stainless steel with excellent ductility. The austenite reversion mechanism is coupled to the kinetic freezing of carbon during low-temperature partitioning at the interfaces between martensite and retained austenite and to carbon segregation at martensite-martensite grain boundaries. An advantage of austenite reversion is its scalability, i.e., changing tempering time and temperature tailors the desired strength-ductility profiles (e.g. tempering at 400{\deg}C for 1 min. produces a 2 GPa ultimate tensile strength (UTS) and 14% elongation while 30 min. at 400{\deg}C results in a UTS of ~ 1.75 GPa with an elongation of 23%). The austenite reversion process, carbide precipitation, and carbon segregation have been characterized by XRD, EBSD, TEM, and atom probe tomography (APT) in order to develop the structure-property relationships that control the material's strength and ductility.Comment: in press Acta Materialia 201

    Soil quality and fertility in sustainable agriculture, with a contribution to the biological classification of agricultural soils

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    Soils and crops are particularly vulnerable to climate change and environmental stresses. In many agrosystems, soil biodiversity and ecosystem services provided by soils are under threat from a range of natural and human drivers. Agricultural soils are often subject to agronomic practices that disrupt soil trophic networks and make soils less productive in the long term. In this scenario, sustainable soil use aimed at improving plant/root status, growth and development plays a crucial role for enhancing the biological capacity of agricultural soils. This commentary paper is divided into the following four main sections: (i) the contentious nature of soil organic matter; (ii) soil biological quality/fertility; (iii) soil classification; and, (iv) which agricultural practices can be defined as sustainable? The published literature was analyzed within a holistic framework, with agrosystems considered as living systems where soil, vegetation, fauna and microorganisms co-evolve and are reciprocally influenced. Ultimately, this article will suggest a better stewardship of agricultural soils as a natural capital

    Hubungan Kepribadian Tipe-d Dengan Koping Klien Akne Vulgaris Di Jurusan Keperawatan Politeknik Kesehatan Kemenkes Manado

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    ; This study aims to identify the relationship of type-D personality with clients coping acne vulgaris. The research method using descriptive analytic cross sectional design, the 120 respondents polytechnic nursing students of Department of Health MoH Manado, period study from April to July 2014. The instrument used was a questionnaire-type-D personality and coping questionnaire. Univariad analysis using frequency distributions are presented in tables and bivariate analysis using Chi-Square. The results of Chi-square analysis with significance level of 95% at α 5% (α = 0.05), obtained by X ² = 13.308 with p (asypm.sig) = 0.000, <0.005, means that there is a significant association between type-D personality in coping clients of acne vulgaris. Conclusion: Type-D personality proved significantly associated with clients coping acne vulgaris, and individuals with a type-D personality tend to have maladaptive coping. Suggestion: the need for student research development of type-D personality and motivation in facing the problem of acne vulgaris

    Vertical distribution of Collembola (Hexapoda) and their food resources in organic horizons of beech forests

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    Wodzicki Residue for Operators on Manifolds with Cylindrical Ends

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    We define the Wodzicki Residue TR(A) for A in a space of operators with double order (m_1,m_2). Such operators are globally defined initially on R^n and then, more generally, on a class of non-compact manifolds, namely, the manifolds with cylindrical ends. The definition is based on the analysis of the associate zeta function. Using this approach, under suitable ellipticity assumptions, we also compute a two terms leading part of the Weyl formula for a positive selfadjoint operator belonging the mentioned class in the case m_1=m_2.Comment: 24 pages, picture changed, added references, corrected typo

    Sound Multi-Party Business Protocols for Service Networks

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    Service networks comprise large numbers of long-running, highly dynamic complex end-to-end service interactions reflecting asynchronous message flows that typically transcend several organizations and span several geographical locations. At the communication level, service network business protocols can be flexible ranging from conventional inter-organizational point-to-point service interactions to fully blown dynamic multi-party interactions of global reach within which each participant may contribute its activities and services. In this paper we introduce a formal framework enriched with temporal constraints to describe multiparty business protocols for service networks. We extend this framework with the notion of multi-party business protocol soundness and show how it is possible to execute a multi-party protocol consistently in a completely distributed manner while guaranteeing eventual termination

    Ultrastrong lightweight compositionally complex steels via dual-nanoprecipitation

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