PLASTICITY CHARACTERISTICS OBTAINED THROUGH INSTRUMENTAL INDENTATION

2007 ◽  
Vol 1049 ◽  
Author(s):  
Yuliy Milman ◽  
Sergey Dub ◽  
Alex Golubenko

AbstractThe nanohardness and microhardness testing of crystalline materials with different types of interatomic bonds and different crystal structures was performed with Berkovich indenter.The plasticity characteristics for crystalline materials with different types of interatomic bonds and different crystalline structures were determined by microindentation and by nanoindentation. The relation between these characteristics and parameters of material (Meyer hardness, Young's modulus and Poisson's ratio) was assigned. Plasticity characteristic may be used for characterization of mechanical behavior of materials which are brittle at standard mechanical tests and for coatings.

2019 ◽  
Vol 195 ◽  
pp. 218-229
Author(s):  
Sophie Samain ◽  
Mikel Leturia ◽  
Stéphane Mottelet ◽  
Mohammed Benali ◽  
Khashayar Saleh

Author(s):  
Anton V. Savchenkov ◽  
Viktor N. Serezhkin

A method for clear visualization of the variation of noncovalent interactions in crystal structures of conformational polymorphs is developed and introduced. The first stage of the method establishes the characteristics of all, without exception, noncovalent interactions in all crystal structures under discussion. This is possible using a strict and objective method of construction of Voronoi–Dirichlet polyhedra within the framework of the stereoatomic model of crystal structures. The second stage of the method then involves plotting of diagrams, showing the relation between parameters characterizing interatomic interactions and chosen geometric parameters of molecules. Application of the title method to highly polymorphic systems of ROY and flufenamic acid allows several imperceptible features of real crystal structures to be revealed and determines the value of different types of interactions in their conformational polymorphs. The method is universal as it can be readily adapted to any system of crystal structures in which noncovalent interactions change as a function of any parameters. Employment of the title method along with quantum chemical calculations offers opportunities for the correlation of potential energy of crystalline materials with noncovalent interactions in their structures, which is a giant step forward towards a more complete understanding of the relationship between the structure and properties of compounds.


2017 ◽  
Vol 3 (2) ◽  
pp. 39
Author(s):  
Enrique Gómez de la Peña ◽  
Alfonso Cobo Escamilla ◽  
Rafael Lozano Díez ◽  
Oscar López Zaldívar

ResumenEste trabajo realiza un estudio comparativo de caracterización de vigas de madera aserradas y su comparación con la normativa. Para ello se ha utilizado dos tipos de madera muy diferentes, una muy heterogenea, con gran número de defectos, y otra muy homogénea, para comprobar la influencia de los nudos en el comportamiento mecánico de la madera. Para ello se han ensayado un total de 18 vigas de madera y 5 probetas a compresión. Posteriormente se ha realizado una comparativa con la normativa de caracterización, para comprobar su grado de definición. Se ha podido comprobar que dicha norma, se encuentra en el lado de la seguridad en el ámbito de las resistencias, pero que su definición es escasa en cuanto al módulo de elasticidad de la madera.AbstractThis work makes a comparative study of the characterization of sawn timber and its comparison with the standard. For this purpose, two very different types of wood have been used, one very heterogeneous, with a large number of defects, and a very homogeneous one, to verify the influence of the knots on the mechanical behavior of the wood. To this end, a total of 18 wooden beams and 5 test specimens have been tested. Subsequently a comparison has been made with the standardization of characterization, to verify its degree of definition. It has been possible to verify that this norm, is in the side of the security in the field of the resistances, but that its definition is scarce as far as the modulus of elasticity of the wood.


Author(s):  
J.B. Posthill ◽  
R.P. Burns ◽  
R.A. Rudder ◽  
Y.H. Lee ◽  
R.J. Markunas ◽  
...  

Because of diamond’s wide band gap, high thermal conductivity, high breakdown voltage and high radiation resistance, there is a growing interest in developing diamond-based devices for several new and demanding electronic applications. In developing this technology, there are several new challenges to be overcome. Much of our effort has been directed at developing a diamond deposition process that will permit controlled, epitaxial growth. Also, because of cost and size considerations, it is mandatory that a non-native substrate be developed for heteroepitaxial nucleation and growth of diamond thin films. To this end, we are currently investigating the use of Ni single crystals on which different types of epitaxial metals are grown by molecular beam epitaxy (MBE) for lattice matching to diamond as well as surface chemistry modification. This contribution reports briefly on our microscopic observations that are integral to these endeavors.


2020 ◽  
Vol 70 (12) ◽  
pp. 4594-4600

The purpose of this study was to characterize some types of biomass wastes resulted from different activities such as: agriculture, forestry and food industry using thermogravimetric and ICP-MS analyses. Also, it was optimized an ICP-MS method for the determination of As, Cd and Pb from biomass ash samples. The ICP-MS analysis revealed that the highest concentration of metals (As, Cd, Pb) was recorded in the wood waste ash sample, also the thermogravimetric analysis indicated that the highest amount of ash was obtained for the same sample (26.82%). The biomass wastes mentioned in this study are alternative recyclable materials, reusable as pellets and briquettes. Keywords: ash, biomass, ICP-MS, minor elements, TG


2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Bruna B. Przybulinski ◽  
Rodrigo G. Garcia ◽  
Maria Fernanda de C. Burbarelli ◽  
Claudia M. Komiyama ◽  
Deivid Kelly Barbosa ◽  
...  
Keyword(s):  

Genetics ◽  
2000 ◽  
Vol 154 (1) ◽  
pp. 437-446 ◽  
Author(s):  
Lisa Girard ◽  
Michael Freeling

Abstract Insertions of Mutator transposons into maize genes can generate suppressible alleles. Mu suppression is when, in the absence of Mu activity, the phenotype of a mutant allele reverts to that of its progenitor. Here we present the characterization of five dominant Mu-suppressible alleles of the knox (knotted1-like homeobox) genes liguleless3 and rough sheath1, which exhibit neomorphic phenotypes in the leaves. RNA blot analysis suggests that Mu suppression affects only the neomorphic aspect of the allele, not the wild-type aspect. Additionally, Mu suppression appears to be exerting its effects at the level of transcription or transcript accumulation. We show that truncated transcripts are produced by three alleles, implying a mechanism for Mu suppression of 5′ untranslated region insertion alleles distinct from that which has been described previously. Additionally, it is found that Mu suppression can be caused by at least three different types of Mutator elements. Evidence presented here suggests that whether an allele is suppressible or not may depend upon the site of insertion. We cite previous work on the knox gene kn1, and discuss our results in the context of interactions between Mu-encoded products and the inherently negative regulation of neomorphic liguleless3 and rough sheath1 transcription.


2021 ◽  
Author(s):  
Zenita Adhireksan ◽  
Deepti Sharma ◽  
Phoi Leng Lee ◽  
Qiuye Bao ◽  
Sivaraman Padavattan ◽  
...  

Abstract Structural characterization of chromatin is challenging due to conformational and compositional heterogeneity in vivo and dynamic properties that limit achievable resolution in vitro. Although the maximum resolution for solving structures of large macromolecular assemblies by electron microscopy has recently undergone profound increases, X-ray crystallographic approaches may still offer advantages for certain systems. One such system is compact chromatin, wherein the crystalline state recapitulates the crowded molecular environment within the nucleus. Here we show that nucleosomal constructs with cohesive-ended DNA can be designed that assemble into different types of circular configurations or continuous fibers extending throughout crystals. We demonstrate the utility of the method for characterizing nucleosome compaction and linker histone binding at near-atomic resolution but also advance its application for tackling further problems in chromatin structural biology and for generating novel types of DNA nanostructures. We provide a library of cohesive-ended DNA fragment expression constructs and a strategy for engineering DNA-based nanomaterials with a seemingly vast potential variety of architectures and histone chemistries.


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