Mechanical and Tribological Properties of TiN Coatings Produced by PIII&D Technique

The structure, mechanical and tribological properties TiN coatings рroduced with PIII&D by using rectilinear filtered vacuum arc plasma system are present. The results of scratch testing and wear reciprocating testing clearly revealed the positive effect of pulse bias (0.5÷2.5 kV) application on tribological behavior of the TiN coatings in comparison the coatings deposited with DC bias (150 V). Application of pulsed bias potential leads to a significant reduction in the friction coefficient and increasing of coatings wear resistance due to a change in their structure. The orientation of crystal planes parallel to the surface changes from (111) to (220) with the application of pulse bias, which is accompanied by a transition from fibrous grains structure to denser columnar grains. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3518

Mechanical and Tribological Properties of TiN Coatings Produced by PIII&D Technique

The structure, mechanical and tribological properties TiN coatings рroduced with PIII&D by using rectilinear filtered vacuum arc plasma system are present. The results of scratch testing and wear reciprocating testing clearly revealed the positive effect of pulse bias (0.5÷2.5 kV) application on tribological behavior of the TiN coatings in comparison the coatings deposited with DC bias (150 V). Application of pulsed bias potential leads to a significant reduction in the friction coefficient and increasing of coatings wear resistance due to a change in their structure. The orientation of crystal planes parallel to the surface changes from (111) to (220) with the application of pulse bias, which is accompanied by a transition from fibrous grains structure to denser columnar grains. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3518

Task-dependent warping of semantic representations during search for visual action categories

Object and action perception in cluttered dynamic natural scenes relies on efficient allocation of limited brain resources to prioritize the attended targets over distractors. It has been suggested that during visual search for objects, distributed semantic representation of hundreds of object categories is warped to expand the representation of targets. Yet, little is known about whether and where in the brain visual search for action categories modulates semantic representations. To address this fundamental question, we studied brain activity recorded from five subjects (1 female) via functional magnetic resonance imaging while they viewed natural movies and searched for either <i>communication</i> or <i>locomotion</i> actions. We find that attention directed to action categories elicits tuning shifts that warp semantic representations broadly across neocortex, and that these shifts interact with intrinsic selectivity of cortical voxels for target actions. These results suggest that attention serves to facilitate task performance during social interactions by dynamically shifting semantic selectivity towards target actions, and that tuning shifts are a general feature of conceptual representations in the brain.<b>SIGNIFICANCE STATEMENT</b>The ability to swiftly perceive the actions and intentions of others is a crucial skill for humans, which relies on efficient allocation of limited brain resources to prioritise the attended targets over distractors. However, little is known about the nature of high-level semantic representations during natural visual search for action categories. Here we provide the first evidence showing that attention significantly warps semantic representations by inducing tuning shifts in single cortical voxels, broadly spread across occipitotemporal, parietal, prefrontal, and cingulate cortices. This dynamic attentional mechanism can facilitate action perception by efficiently allocating neural resources to accentuate the representation of task-relevant action categories

WTC2005-64056 COMPARATIVE TRIBOLOGICAL BEHAVIOR OF TiN-, CrN-, ZrN-, AND MoN -Cu BASED NANOCOMPOSITE COATINGS

ABSTRACT Nanocomposite structures composed of hard and soft phases are very promising candidates for tribological applications involving both dry and lubricated sliding. This study aims to compare the wear behavior of copper doped hard nanocomposite nitride coatings under dry and lubricated sliding conditions. These nanocomposite coatings are produced in a cathodic arc-based hybrid PVD coating system and their mechanical and structural properties are fully characterized using electron microscopy and other relevant techniques. Tribological tests were performed in pin on disc and reciprocating wear test machines under dry and lubricated sliding conditions. The differences observed in the tribological behavior of nanocomposite coatings are discussed by taking into consideration the structure and mechanical properties of the coatings and the chemical character of the tribo films formed on sliding surfaces during wear testing INTRODUCTION Nanocomposite structures composed of immiscible metal nitrides and soft metals such as copper and silver are first introduced by Musil and co-workers [1]. After then numerous studies are conducted on the structure and production methods of these coatings Previous studie

Genetic characterization of Toxoplasma gondii isolates and toxoplasmosis seroprevalence in stray cats of Izmir, Turkey

PubMed ID: 25127360Currently, some Toxoplasma gondii genotypes are being associated with serious clinical presentations. A recent report showing the Africa 1 genotype in two local congenital toxoplasmosis cases acquired in Turkey formed the basis of this study because atypical Africa 1 genotype is most frequently detected in animals and patients from sub-Saharan Africa. Since stray cats are considered as the linkage between wild life and urban life in T. gondii transmission, the present study aimed to isolate and characterize T. gondii strains circulating in stray cats of İzmir (Western Turkey). A secondary objective was to determine toxoplasmosis seroprevalence in this cat population. Tissues obtained from 100 deceased stray cats were bioassayed and isolated strains were genotyped using 15 microsatellite markers. In addition, toxoplasmosis seroprevalence was analyzed in 1121 cat sera collected from several large veterinary clinics in İzmir. Among the 22 isolates, 19 were Type II (86.3%), two were Type III (9%) and one was Africa 1 genotype (4.5%). The overall seropositivity rates in cats were 42-48% and 33.4-34.4% according to IFA and ELISA, respectively. Seroprevalence in deceased cats was significantly higher than in healthy cats (P = 0.0033). Finding both the major clonal Type II lineage together with the Type III lineage also found in Middle East, and an atypical genotype, Africa 1 appears consistent with the specific geographic location of Turkey between three continents and raises the possibility of transportation of these strains between continents through trade routes or long distance migratory birds. In addition, the first large study of toxoplasma seroprevalence in a stray cat population was also reported. The relatively high seropositivity rates and the variety of T. gondii genotypes confirm the local stray cat population as a risk factor for human toxoplasmosis in İzmir. © 2014 Can et al