1,724,091 research outputs found
Development of a Microstructure-Based Finite Element Model of Thermomechanical Response of a Fully Metallic Composite Phase Change Material
No full textREGIONAL PECULIARITIES OF THE WORKS BY I. NAUMENKO
No full textУ артыкуле разглядаюцца асаблівасці ўжывання анамастычных адзінак у творах Івана Навуменкі. = This article deals with the usage of named units in the works by I. Naumenko. They play a significant part in the reflection of autobiographical units his works and of regional colour of Polessie, its originality and uniqueness
Experimental analysis and constitutive modeling of anisotropic creep damage in a wrought age-hardenable Al alloy
No full textMany components of aerospace and automotive engineering manufactured from forged age-hardening aluminum alloys operate at high temperature in the range 0.3Tm–0.5Tm, where Tm is the melting temperature. Experimental data for uni-axial creep on specimens sampled from a forged AA2014 alloy component show that inelastic strain rates depend significantly on the orientation of loading with respect to the material flow direction during the manufacturing stage. Based on the recently developed constitutive model of anisotropic creep, hardening/recovery, softening and overageing processes, this paper addresses experimental analysis and modeling tertiary creep regime up to the final stage of creep rupture. The emphasis is placed on the damage evolution equation in order to account for different damage mechanisms depending on the loading mode and loading direction relative to grain axis: cavitation on elongated grain boundaries as well as decohesions and microcracks around and inside coarse grain particles. Experimental data of creep strain rates for longitudinal and transverse loading directions at 130, 150 and 170 °C have been used to calibrate the model. The validation of the model was carried out by comparing experimental and modeled creep curves in the case of a 30°angle between the loading and the material flow direction during forging. The results show that the assumed damage mechanisms and the developed damage evolution equation are able to reflect both the anisotropic accelerated creep and the time to creep rupture for different stress levels and loading directions
A phase mixture model for anisotropic creep of forged Al-Cu-Mg-Si alloy
No full textAluminium wrought alloys are frequently applied to manufacture structural components of complex
shape and used in a temperature range where creep phenomena take place.The aim of this paper is to
analyze creep behavior of forged AA2014 alloy and to develop a constitutive model to describe inelastic
response undermulti-axial stress state. Experimental data show that creep rates depend essentially on
the loading direction within the power law creep regime,while in the power law breakdown range creep
anisotropy is not essential and can be neglected.Microstructural observation suggest that the
anisotropy of creep is primarily caused by elongated grains and grain boundaries as are suit of material
processing. Assuming the inhomogeneous deformation indifferent microstructural zones including
interiors of elongated grains and grain boundary regions,a phase mixture model of inelastic deformation
is developed.The model include constitutive equations for individual phases and an interaction rule to
capture the direction dependent creep.Additional state variables including the normalized dislocation
density and the normalized particle size as well as corresponding evolution equations are introduced to
describe hardening/recovery and over aging processes.Through a change of variables the modelis
reduced to a set of kinetic equations such that the material parameters can be identified from families of
creep curves for two loading directions.Results of identification are presented for the temperature of
1501C and several stress levels
INA complex links assembly of the nuclear- and mitochondrial-encoded modules of ATP synthase.
No full textV.P. Naumenko cultural and educational activity (second half of XIX century - 1917 year)
No full textУ статті досліджується культурно-освітня діяльність В.П. Науменка (1852-1919) у період з кінця ХІХ ст. до революційних подій 1917 р. В.П. Науменко - видатний представник української інтелігенції кінця XIX -
початку ХХ ст., політик, філолог, видавець, педагог. Культурницька і просвітницька діяльність вченого розгорталася під впливом визвольних ідей в зазначений період, про що свідчать численні праці видатних істориків, які були сучасниками В.П. Науменка, а також дослідників кінця ХХ - початку XXI ст.В статье исследуется культурно-образовательная деятельность В.П. Науменко (1852-1919) в период с конца XIX в. до революционных событий 1917г. В.П. Науменко - выдающийся представитель украинской интеллигенции конца XIX - начала ХХ в., политик, филолог, издатель, педагог. Культурная и просветительская деятельность ученого разворачивалась под влиянием освободительных идей в указанный период, о чем свидетельствуют многочисленные труды выдающихся историков, современников В.П. Науменко, а также исследователей конца ХХ - начала XXI в.The article cultural and educational activity V.P. Naumenko (1852-1919) - an
outstanding representative of Ukrainian intelligentsia of the late XIX-early XX century,
politician, philologist, publisher, teacher. Activity scientist unfolded under the influence of
liberating ideas in this period. This is evidenced by the numerous works of eminent historians
who were contemporaries V.P. Naumenko, as well as researchers of the late XX-early XXI
century.Analysis of documentary material proved that the impetus for an active outreach
Vladimir Naumenko was the family education, where the service of the people attached great
importance. Significant influence on the formation of personality V.P. Naumenko had a Second
gymnasium of Kiev and Kiev University of St. Vladimir.
An important role in the life of a scientist was his work in the Kiev sodality, where he
has soon established himself as an excellent orator. Sometimes V.P. Naumenko served as
treasurer, and then partially Acting Head sodality.
A separate page of cultural and educational activities of V.P. Naumenko - his relationship
with M.P. Drahomanov. Because of the Ems Edict 1876 M.P. Drahomanov was forced to leave
the country and emigrate. Vladimir Pavlovich always maintained his mentor and helped him
publish a book «Hromada».
Almost all his life Vladimir Pavlovich dedicated educational activities of the future
generation. After graduation, he returned to his native school as a teacher and worked there
for about 30 years. In addition, the scientist has taught in a number of other prestigious
educational institutions in Kiev. V.P. Naumenko has gained wide acceptance among the
population and has been awarded many prizes. Since 1905 teacher realizes himself as the
director of the Kiev private school. This school was founded in 1905 as an initiative group of
parents who had school-age children. Here Vladimir Pavlovich showed his professionalism in
the conduct of school affairs, as evidenced by the memories of his students. One of his pupils
was the famous M.T. Rylsky, which in 1908 began studying at the school.
V.P. Naumenko did a lot for the enlightenment of the Ukrainian people. For example of
such vigorous activity may serve as his work in the Kiev society literacy. In 1897 the teacher
began to occupy the post of the first chapter of this organization and has always said that his
main job, he sees «serve the cause of education of the people ....».
Thus, the article analyzes the cultural and educational activities V.P. Naumenko and
his role in the process of enlightenment Ukrainians in the period from the middle of the XIX
century before the start of the 1917 revolution
Memoirs of contemporaries of Volodymyr Naumenko as a source of research of his biography
No full textУ тезах розглянуто cпогади сучасників Володимира Науменка як джерело дослідження його біографії.The abstract consider the memoirs of contemporaries of Volodymyr Naumenko as a source of research of his biography
INA complex links assembly of the nuclear- and mitochondrial-encoded modules of ATP synthase.
No full textNew species of the genus Juno Tratt. (Iridaceae) from Kyrgyzstan
No full textA new species Juno rodionenkoi Lazkov et Naumenko from Kyrgyzstan is described. Morphological description and differences from related species Juno narbutii (O. Fedtsch.) Vved. are given
Wave dispersion relations in peridynamics: Influence of kernels and similarities to nonlocal elasticity theories
No full textWe investigate the wave dispersion relations of an infinite elastic bar within the framework of linear bond-based peridynamics. This nonlocal integral-type model accounts for long-range interactions, which become significant at small scales and in cases of damage and fracture. Since a key element of this material model is the kernel function, we derive dispersion curves for several kernel choices. Notably, for non-singular kernels, we observe negative group velocities, indicating that peridynamics can describe materials with anomalous dispersion. By comparing one-dimensional (1D) peridynamics with the 1D nonlocal elasticity of Eringen's type, we highlight similarities between the two models in terms of dispersion behavior
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