Processing Path and The Evolution of Crystallinity in Rapidly Solidified Glassy Alloys

1994 ◽  
Vol 362 ◽  
Author(s):  
M. A. Otooni
Keyword(s):  
Transition Temperature ◽  
Thermomechanical Properties ◽  
Relaxation Processes ◽  
Linear Temperature Dependence ◽  
Linear Temperature ◽  
Glassy Alloys ◽  
Atomic Transport ◽  
The Subject ◽  
Rapidly Solidified ◽  
Selection Of

AbstractAtomic transport properties in rapidly solidified glassy alloys are not fully understood in spite of much experimental data on the subject. Nevertheless, a thorough understanding of these properties is of fundamental importance when studying the practical limits of the application of rapidly solidified glassy alloys.Several attempts are made in this paper to explain our experimental results on the mechanical flow properties near the transition temperature, Tr. These results are interpreted in the context of possible operating mechanisms such as diffusion and/or relaxation processes. Some inferences have been made on the nature of viscosity and its fluctuation near the transition temperature. The linear temperature dependence of the viscosity near the transition temperature is explained by invoking the free-volume concept for the viscosity of the glassy alloys.These results are used to provide appropriate data for the selection of feasible processing paths which will produce alloys with advanced thermomechanical properties.

scholarly journals High-temperature effect on the material constants and elastic moduli for solid rocks

2021 ◽  
Vol 18 (4) ◽  
pp. 583-593
Author(s):  
Jian Yang ◽  
Li-Yun Fu ◽  
Bo-Ye Fu ◽  
Zhiwei Wang ◽  
Wanting Hou
Keyword(s):  
Temperature Dependence ◽  
High Temperatures ◽  
Elastic Moduli ◽  
Constitutive Relations ◽  
Thermomechanical Properties ◽  
Linear Temperature Dependence ◽  
Free Energy Function ◽  
Linear Temperature ◽  
Material Constants ◽  
Geologic Materials

Abstract Thermally coupled constitutive relations are generally used to determine material constants and elastic moduli (Young's modulus and shear modulus) of solid media. Conventional studies on this issue are mainly based on the linear temperature dependence of elastic moduli, whereas analytical difficulties are often encountered in theoretical studies on nonlinear temperature dependence, particularly at high temperatures. This study investigates the thermally coupled constitutive relations for elastic moduli and material constants using the assumption of axisymmetric fields, with applications to geologic materials (marble, limestone and granite). The Taylor power series of the Helmholtz free energy function within dimensionless temperatures could be used to develop the thermally coupled constitutive relations. The thermoelastic equivalent constitutive equations were formulated under the generalized Hooke's law. The material constants of solid rocks were determined by fitting experimental data using axisymmetric stress and strain fields at different temperatures, based on their thermomechanical properties. For these geologic materials, the resultant equivalent elastic moduli and deformations were in good agreement with those from the experimental measurements. Thermal stresses, internal moisture evaporation and internal rock compositions significantly affected the experimental results. This study provides a profound understanding of the thermally coupled constitutive relations that are associated with the thermomechanical properties of solid rocks exposed to high temperatures.

DOPING AND TEMPERATURE DEPENDENCE OF SUPERFLUID DENSITY IN KINETIC ENERGY DRIVEN CUPRATE SUPERCONDUCTORS

2010 ◽  
Vol 24 (29) ◽  
pp. 2845-2854
Author(s):  
ZHEYU HUANG ◽  
HUAISONG ZHAO ◽  
SHIPING FENG
Keyword(s):  
Transition Temperature ◽  
Kinetic Energy ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
Cuprate Superconductors ◽  
Superfluid Density ◽  
Linear Temperature Dependence ◽  
Superconducting Transition ◽  
Zero Temperature ◽  
Linear Temperature

Within the kinetic energy driven superconducting mechanism, the doping and temperature dependence of the superfluid density in cuprate superconductors is studied throughout the superconducting dome. It is shown that the superfluid density shows a crossover from the linear temperature dependence at low temperatures to a nonlinear one in the extremely low temperatures. In analogy to the dome-like shape of the doping dependent superconducting transition temperature, the maximal zero-temperature superfluid density occurs around the critical doping δ ≈ 0.195, and then decreases in both lower doped and higher doped regimes.

Elastic Properties of Cu-Based Bulk Metallic Glass around Glass Transition Temperature

2007 ◽  
Vol 539-543 ◽  
pp. 1932-1936 ◽  
Author(s):  
R. Tarumi ◽  
H. Ogi ◽  
M. Hirao ◽  
T. Ichitsubo ◽  
Eiichiro Matsubara ◽  
...  
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Acoustic Resonance ◽  
Supercooled Liquid ◽  
Elastic Behavior ◽  
Linear Temperature Dependence ◽  
Linear Temperature

Temperature dependent elastic constants Cij(T) of Cu60Hf30Ti10 bulk metallic glass (BMG) have been investigated in a MHz frequency range using electromagnetic acoustic resonance (EMAR) up to 823 K. At room temperature, the BMG showed high Poisson’s ratio ν arising from low shear modulus G compared with that of constitutive crystalline elements. With increasing temperature, G showed usual linear temperature dependence while it suddenly drops around glass transition temperature, Tg. Within a framework of quasiharmonic approximation, Grüneisen parameter γ around Tg is estimated to be 10. This extremely large γ indicates the high anhramonicity of long wavelength limit acoustic mode phonon in the supercooled liquid state. The unusual elastic behavior can be interpreted on the basis of heterogeneous microstructure.

Thomas More’s Correspondence in a Spanish Ambiance

Moreana ◽  
2002 ◽  
Vol 39 (Number 149) (1) ◽  
pp. 41-60 ◽  
Author(s):  
Eugenio M. Olivares Merino
Keyword(s):  
The Subject ◽  
Selection Of

The recent reprinting of Álvaro de Silva’s 1998 edition of a selection of More’s letters prompts the author to examine the subject of Spanish translations of More, and of de Silva’s general commentary on More’s correspondence and on his relationship to other humanists. The author reflects on aspects of More’s personality as exposed in his letters and uses what he finds as a corrective to several biographical misconceptions. He points out the strengths and weaknesses of de Silva’s work and compares it with that of other translators, particularly Elizabeth Rogers, and notes the particularly Spanish quality of de Silva’s edition.

Features of radiothermoluminescence of polypropylene and ethylene propylenediene elastomer SKEPT-4044 compositions with nanoscale metal-containing fillers

2020 ◽  
pp. 66-73
Author(s):  
A.M. Magerramov ◽  
◽  
N.I. Kurbanova ◽  
M.N. Bayramov ◽  
N.A. Alimirzoyeva ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Molecular Mobility ◽  
Fe3o4 Nanoparticles ◽  
Low Temperatures ◽  
Frost Resistance ◽  
Relaxation Processes ◽  
Ethylene Propylene ◽  
Temperature Range ◽  
Β Relaxation

Using radiothermoluminescence (RTL), the molecular mobility features in the temperature range of 77-300 K were studied for the polypropylene (PP)/ethylene propylene diene elastomer SKEPT-4044 with NiO, Cu2O and Fe3O4 nanoparticles (NPs) based on ABS-acrylonitrile butadiene or SCS-divinyl styrene matrices. It has been shown that the introduction of nanofillers in PP significantly affects the nature and temperature of γ- and β-relaxation processes, while the region of manifestation of the β-process noticeably shifts to the region of low temperatures. Composites with Cu2O NPs have a higher β-transition temperature Tβ than composites with other NPs. It was found that PP/SKEPT-4044 composites with Cu2O NPs with a dispersion of 11-15 nm and acrylonitrile butadiene thermoplastics have optimal frost resistance compared to other compositions.

Tanks in the Spa Town. The New Book about the Events of the Year 1968 in Czechoslovakia

2019 ◽  
Vol 14 (1-2) ◽  
pp. 278-282
Author(s):  
Kirill A. Popov
Keyword(s):  
Fiftieth Anniversary ◽  
Warsaw Pact ◽  
Scientific Event ◽  
The Social ◽  
Prague Spring ◽  
The Subject ◽  
Scientific Terms ◽  
Selection Of ◽  
Regional Perspective ◽  
The Way

This review is devoted to the monograph by Jan Nedvěd “We do not decline our heads. The events of the year 1968 in Karlovy Vary”. The Karlovy Vary municipal museum coincided its publishing with the fiftieth anniversary of the Prague spring which, considering the way of the presentation, turned the book not only to scientific event but also to the social one. The book describes sociopolitical trends in the region before the year 1968, the development of the reformist movement, the invasion and advance of the armies of the Warsaw Pact countries, and finally the decline of the reformist mood and the beginning of the normalization. Working on his writing, the author deeply studied the materials of the local archive and gathered the unique selection of the photographs depicting the passage of the soviet army through the spa town and the protest actions of its inhabitants. In the meantime, Nedvěd takes undue freedom with scientific terms, and his selection of historiography raises questions. The author bases his research on the Czech papers and scarcely uses the books of Russian origin. He also did not study the subject of the participating of the GDR’s army in the operation Danube, although these troops were concentrated on the borders of Karlovy Vary region as well. Because of this decision, there are no materials from German archives or historiography in the monograph. In general, the work lacks the width of studying its subject, but it definitively accomplishes the task of depicting the Prague spring from the regional perspective.

Determination of integral indicators characterizing the possibility of accommodating the evacuated population in the territory of the Republic of Kazakhstan

2020 ◽  
pp. 154851292097028
Author(s):  
Yernar Zh Akimbayev ◽  
Zhumabek Kh Akhmetov ◽  
Murat S Kuanyshbaev ◽  
Arman T Abdykalykov ◽  
Rashid V Ibrayev
Keyword(s):  
Statistical Data ◽  
Armed Conflicts ◽  
Security Issues ◽  
Inaccurate Information ◽  
The Subject ◽  
The Republic ◽  
The Impact ◽  
Integrated Indicators ◽  
Selection Of

Studying the historical facts of past wars and armed conflicts and natural and man-made emergencies, today in the Republic of Kazakhstan one of the most important security issues is the preparation and organization of the evacuation of the population from possible dangerous zones, taking into account the emergence of new threats to the country’s security. The paper presents an algorithm for constructing universal scales of the distribution function of opportunities by types of support and rebuilding them into subject scales using display functions. The purpose of the paper is to determine the integral indicators characterizing the possibility of accommodation of the evacuated population and the impact on resources during relocation. On the subject scales of cities and districts of the region, indicators of the possibility of relocation of a certain amount of the evacuated population by types of support and indicators characterizing the impact on the district’s resources during resettlement of a certain amount of the evacuated population are determined. It was concluded that the use of integrated indicators allows the selection of areas to accommodate the evacuated population without the use of statistical data, in conditions of incomplete and inaccurate information. The presented method does not replace traditional methods based on classical methods of territory assessment by the level of life sustenance, but also allows their reasonable combination with the experience of specialists in this field, taking into account the incompleteness, uncertainty, and inconsistency of the initial data of the study area, which does not allow the application of existing methods.

New Fe-Ni Based Metal-Metalloid Glassy Alloys Prepared by Mechanical Alloying and Rapid Solidification

1996 ◽  
Vol 455 ◽  
Author(s):  
J. J. Suñol ◽  
M. T. Clavaguera-Mora ◽  
N. Clavaguera ◽  
T. Pradell
Keyword(s):  
Mechanical Alloying ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Magnetic Interaction ◽  
Processing Route ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Glassy Alloys ◽  
Rapidly Solidified ◽  
Thermal Stability Of

ABSTRACTMechanical alloying and rapid solidification are two important routes to obtain glassy alloys. New Fe-Ni based metal-metalloid (P-Si) alloys prepared by these two different processing routes were studied by differential scanning calorimetry and transmission Mössbauer spectroscopy. Mechanical alloyed samples were prepared with elemental precursors, and different nominal compositions. Rapidly solidified alloys were obtained by melt-spinning. The structural analyses show that, independent of the composition, the materials obtained by mechanical alloying are not completely disordered whereas fully amorphous alloys were obtained by rapid solidification. Consequently, the thermal stability of mechanically alloyed samples is lower than that of the analogous material prepared by rapid solidification. The P/Si ratio controls the magnetic interaction of the glassy ribbons obtained by rapid solidification. The experimental results are discussed in terms of the degree of amorphization and crystallization versus processing route and P/Si ratio content.

Singular agreement in there-existentials

2012 ◽  
Vol 33 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Peter Collins
Keyword(s):  
Indirect Evidence ◽  
World Englishes ◽  
Relative Influence ◽  
Evolutionary Status ◽  
The Subject ◽  
Characteristic Style ◽  
Selection Of

The phenomenon of “singular agreement” (“SA”) in there-existentials — the combination of a plural post-verbal notional subject and a singular verb — has been the subject of a number of studies which have confirmed its covariation with a range of social, stylistic and grammatical factors. Whereas the focus of most such studies has been on the relative influence of these factors, that of the present study is on the nature and frequency of SA across (a selection of eight) World Englishes. Beginning with the assumption, for which there is indirect evidence in the literature, that SA is on the rise in contemporary English, an attempt is made to relate the degree of advancement of the eight varieties to their evolutionary status and characteristic style orientations.

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