A unified creep-plasticity model suitable for thermo-mechanical loading

An experimentally based unified creep-plasticity constitutive model was implemented for 1070 steel. Accurate rate and temperature effects were obtained for isothermal and thermo-mechanical loading by incorporating deformation mechanisms into the constitutive equations in a simple way

Morphological Productivity in the Lexicon

In this paper we outline a lexical organization for Turkish that makes use of lexical rules for inflections, derivations, and lexical category changes to control the proliferation of lexical entries. Lexical rules handle changes in grammatical roles, enforce type constraints, and control the mapping of subcategorization frames in valency-changing operations. A lexical inheritance hierarchy facilitates the enforcement of type constraints. Semantic compositions in inflections and derivations are constrained by the properties of the terms and predicates. The design has been tested as part of a HPSG grammar for Turkish. In terms of performance, run-time execution of the rules seems to be a far better alternative than pre-compilation. The latter causes exponential growth in the lexicon due to intensive use of inflections and derivations in Turkish.Comment: 10 pages LaTeX, {lingmacros,avm,psfig}.sty, 1 figure, 1 bibtex fil

Twin nucleation in Fe-based bcc alloys - Modeling and experiments

We develop an analytical expression for twin nucleation stress in bcc metal and alloys considering generalized planar fault energy and the dislocations bounding the twin nucleus. We minimize the total energy to predict the twinning stress relying only on parameters that are obtained through atomistic calculations, thus excluding the need for any empirical constants. We validate the present approach by means of precise measurements of the onset of twinning in bcc Fe-50at% Cr single crystals showing excellent agreement. The experimental observations of the three activated slip systems of symmetric configuration in relation to the twinning mechanism are demonstrated via transmission electron microscopy techniques along with digital image correlation. We then confirm the validity of the model for Fe, Fe-25at% Ni and Fe-3at% V alloys compared with experiments from the literature to show general applicability

Twin migration in Fe-based bcc crystals: Theory and experiments

We establish an overall energy expression to determine the twin migration stress in bcc metals. Twin migration succeeds twin nucleation often after a load drop, and a model to establish twin migration stress is of paramount importance. We compute the planar fault energy barriers and determine the elastic energies of twinning dislocations including the role of residual dislocations (br) and twin intersection types such as 1 1 0, 1 1 3 and 2 1 0. The energy expression derived provides the twin migration stress in relation to the twin nucleation stress with a ratio of 0.5-0.8 depending on the resultant residual burgers vector and the intersection types. Utilizing digital image correlation, it was possible to differentiate the twin nucleation and twin advancement events experimentally, and transmission electron microscopy observations provided further support to the modelling efforts. Overall, the methodology developed provides an enhanced understanding of twin progression in bcc metals, and most importantly the proposed model does not rely on empirical constants. We utilize Fe-50at.%Cr in our experiments, and subsequently predict the twin migration stress for pure Fe, and Fe-3at.%V from the literature showing excellent agreement with experiments. © 2014 Taylor & Francis

A Sign-Based Phrase Structure Grammar for Turkish

This study analyses Turkish syntax from an informational point of view. Sign based linguistic representation and principles of HPSG (Head-driven Phrase Structure Grammar) theory are adapted to Turkish. The basic informational elements are nested and inherently sorted feature structures called signs. In the implementation, logic programming tool ALE (Attribute Logic Engine) which is primarily designed for implementing HPSG grammars is used. A type and structure hierarchy of Turkish language is designed. Syntactic phenomena such a s subcategorization, relative clauses, constituent order variation, adjuncts, nomina l predicates and complement-modifier relations in Turkish are analyzed. A parser is designed and implemented in ALE.Comment: MS. Thesis, Dept. of Computer Engineering, Middle East Technical University, Ankara January, 1996, 97 pages. 5 eps figures, uses avm,psfig,lingmacros,tree-dvips,ulem,QobiTree,alltt ulem.sty,QobiTree.sty,alltt.sty and eps files included in ta

Mitochondrial carrier homolog 1 (Mtch1) antibodies in neuro-Behçet's disease

Cataloged from PDF version of article.Efforts for the identification of diagnostic autoantibodies for neuro-Behcet's disease (NBD) have failed. Screening of NBD patients' sera with protein macroarray identified mitochondrial carrier homolog 1 (Mtch1), an apoptosis-related protein, as a potential autoantigen. ELISA studies showed serum Mtch1 antibodies in 68 of 144 BD patients with or without neurological involvement and in 4 of 168 controls corresponding to a sensitivity of 47.2% and specificity of 97.6%. Mtch1 antibody positive NBD patients had more attacks, increased disability and lower serum nucleosome levels. Mtch1 antibody might be involved in pathogenic mechanisms of NBD rather than being a coincidental byproduct of autoinflammation. © 2013 Elsevier B.V

Computational modelling of full interaction between crystal plasticity and oxygen diffusion at a crack tip

Oxidation-promoted crack growth, one of the major concerns for nickel-based superalloys, is closely linked to the diffusion of oxygen into the crack tip. The phenomenon is still not well understood yet, especially the full interaction between oxygen diffusion and severe near-tip mechanical deformation. This work aimed at the development of a robust numerical strategy to model the full coupling of crystal plasticity and oxygen diffusion in a single crystal nickel-based superalloy. In order to accomplish this, finite element package ABAQUS is used as a platform to develop a series of user-defined subroutines to model the fully coupled process of deformation and diffusion. The formulation allowed easy incorporation of nonlinear material behaviour, various loading conditions and arbitrary model geometries. Using this method, finite element analyses of oxygen diffusion, coupled with crystal plastic deformation, were carried out to simulate oxygen penetration at a crack tip and associated change of near-tip stress field, which has significance in understanding crack growth acceleration in oxidation environment. Based on fully coupled diffusion-deformation analyses, a case study was carried out to predict crack growth rate in oxidation environment and under dwell-fatigue loading conditions, for which a two-parameter failure criterion, in terms of accumulated inelastic strain and oxygen concentration at the crack tip, has been utilized

Could tear endothelin-1 levels be associated with disability in multiple sclerosis?

Background: Endothelin-1 (ET-1) is a potent vasoconstrictor substance mainly secreted by endothelial cells. Increased ET-1 levels in plasma or cerebrospinal fluid (CSF) have been identified in multiple sclerosis (MS). We aimed to analyze tear ET-1 levels; visual evoked potential (VEP) and disability scores in patients with MS and in healthy controls. Methods: Adult patients (18-65 year-old) diagnosed with MS according to the McDonald criteria, and healthy controls were recruited for the study. Demographic features, VEP, and tear ET-1 levels were evaluated. Disability in the MS group was assessed and grouped by EDSS score (= 3). The EDSS score in healthy controls was zero. Results: Both in the total number of patients overall and in the patients with EDSS score = 3 than in those with EDSS score <3 (p<0.001). The tear ET-1 level was positively correlated with age and EDSS score in the MS group (p<0.001). Conclusion: To the best of our knowledge, there is no study in the literature that measures tear ET-1 levels in MS and examines their relationship with EDSS score and VEP. Higher tear ET-1 levels seem to be associated with disability and abnormal VEP in MS. Tear ET-1 measurement may be a simple new noninvasive marker indicating the disability in the patients with MS in the future

Organizational Sacralization: Scale Development and Validation

This study aims to develop the Organizational Sacralization Scale, organizational sacralization involving how the concept of the sacred, the existence of which dates back to the earliest periods of humanity, is currently re-flected in organizations. This study first tests the content validity of the Organizational Sacralization Scale. The next stage is the pilot study phase, in which validity and reliability tests are conducted for the scale using data obtained from 116 white-collar employees. The next stage tests the construct validity of the scale within the scope of data obtained from 215 white-collar employees. The research results show the concept of organizational sacralization to be a scientifically measurable and psychometrically valid and reliable concept consisting of 13 items in three subdi-mensions: seeking meaning, providing meaning, and legitimating meanin