Ultrasonic study of liquid-quenched sulfur from room temperature to 200 °C

1994 ◽  
Vol 9 (12) ◽  
pp. 3170-3173 ◽  
Author(s):  
Akira Doi ◽  
Satoru Kariya ◽  
Hiroaki Kamioka
Keyword(s):  
Thermal Analysis ◽  
Room Temperature ◽  
Polymerization Process ◽  
Structural Units ◽  
Ultrasonic Study ◽  
Temperature Range ◽  
The Difference ◽  
Increasing Temperature

When liquid S is heated above 159 °C, the S8 rings (which are the dominant structural units below this temperature) break open and polymerize into helical chains (S∞). Therefore, samples quenched from liquids at temperatures above or below 159 °C would be different in various properties by the difference in the amount of S∞. The present ultrasonic study of liquid-quenched S in the temperature range from room temperature to 200 °C has revealed this difference. It has been demonstrated that ultrasonics is as powerful as a conventional thermal analysis in dealing with the variation of a material with increasing temperature, even though both techniques were found to be relatively insensitive to the polymerization process.

Plastic Deformation of Mo(Si,Al)2 Single Crystals with the C40 Structure

1996 ◽  
Vol 460 ◽  
Author(s):  
M. Moriwaki ◽  
K. Ito ◽  
H. Inui ◽  
M. Yamaguchi
Keyword(s):  
Single Crystals ◽  
Deformation Behavior ◽  
Basal Slip ◽  
Room Temperature ◽  
Slip Systems ◽  
Temperature Range ◽  
Al Content ◽  
Partial Dislocations ◽  
Increasing Temperature ◽  
Critical Resolved Shear Stress

ABSTRACTThe deformation behavior of single crystals of Mo(Si,Al)2 with the C40 structure has been studied as a function of crystal orientation and Al content in the temperature range from room temperature to 1500°C in compression. Plastic flow is possible only above 1100°C for orientations where slip along <1120> on (0001) is operative and no other slip systems are observed over whole temperature range investigated. The critical resolved shear stress for basal slip decreases rapidly with increasing temperature and the Schmid law is valid. Basal slip appears to occur through a synchroshear mechanism, in which a-dislocations (b=1/3<1120>) dissociate into two synchro-partial dislocations with the identical Burgers vector(b*1/6<1120>) and each synchro-partial further dissociates into two partials on two adjacent planes.

scholarly journals Experimental Study on Wet Skid Resistance of Asphalt Pavements in Icy Conditions

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1201 ◽  
Author(s):  
Yan ◽  
Mao ◽  
Zhong ◽  
Zhang ◽  
Zhang
Keyword(s):  
Surface Friction ◽  
Melting Process ◽  
Asphalt Pavements ◽  
Skid Resistance ◽  
Ice Melting ◽  
Temperature Range ◽  
Bitumen Emulsion ◽  
Image Measure ◽  
The Difference ◽  
Increasing Temperature

In this research, the durability of skid resistance during the ice melting process with temperature increasing from −5 °C to 10 °C was characterized by means of a British Pendulum Skid Tester. Four types of pavement surfaces were prepared and tested. The difference between two antiskid layers prepared with bitumen emulsion was the aggregate. The detailed angularity and form 2D index of fine aggregates used for antiskid surfaces, characterized by means of the Aggregate Image Measure System (AIMS) with micro image analysis methods, were then correlated with British Pendulum Number (BPN) values. Results indicate that skid resistance has the lowest value during the ice-melting process. The investigated antiskid layers can increase the surface friction during icy seasons. In icy conditions, the skid resistance behavior first worsens until reaches the lowest value, and then increases gradually with increasing temperature. Results from ice-melting conditions on four investigated pavement surfaces give the same temperature range where there will be lowest skid resistance. That temperature range is from 3 °C to 5 °C. A thicker ice layer will result in a lower skid resistance property and smaller “lowest BPN”.

Temperature Dependence of Fracture Toughness of the Cubic (L12) Titanium Trialuminides

1996 ◽  
Vol 460 ◽  
Author(s):  
R. A. Varin ◽  
L. Zbroniec
Keyword(s):  
Fracture Toughness ◽  
Stress Intensity Factor ◽  
Room Temperature ◽  
Maximum Load ◽  
Gradual Transition ◽  
Transgranular Cleavage ◽  
Temperature Range ◽  
Temperature Fracture ◽  
Increasing Temperature ◽  
Work Of Fracture

ABSTRACTFracture toughness vs. temperature of the cubic (L12), Mn- modified titanium trialuminide (based on Al3Ti) was investigated in air at the temperature range up to 1000°C. Toughness calculated from the maximum load exhibits a broad peak (KQ≈7–10 MPara0,5) at the 200- 500°C temperature range and then decreases with increasing temperature, reaching a room temperature value of ∼4.5 MPam0.5 at 1000°C. However, the work of fracture (γWOF, J/m2) and the stress intensity factor calculated from it (KIWOF) increases continuously with increasing temperature. Fracture modes exhibit a gradual transition from transgranular cleavage at room temperature to predominantly intergranular failure at the 800- 1000°C range.

Thermal Diffusivity and Phase Transition of Rare Earth Manganites

2006 ◽  
Vol 321-323 ◽  
pp. 1695-1698 ◽  
Author(s):  
Migaku Kobayashi ◽  
Hirohisa Sato ◽  
Yoshihiko Hiyoshi ◽  
Naoki Kamegashira ◽  
Doh Jae Lee ◽  
...  
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Transition Temperature ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Laser Flash ◽  
Oxygen Nonstoichiometry ◽  
Flash Method ◽  
X Ray ◽  
Increasing Temperature

Thermal diffusivity of nonstoichiometric PrMnO3 and NdMnO3 phases were measured by laser flash method from room temperature to 1100 K, in addition to the data of electrical conductivity, thermal analysis and high temperature X-ray diffractometry to detect the phase transition. The thermal diffusivity curve varied with increasing temperature and showed a clear anomaly with a sudden dip at the phase transition temperature. The transition temperature decreases with oxygen nonstoichiometry in each phase.

Thermophysical Properties of Germanium for Thermal Analysis of Growth from the Melt

1981 ◽  
Vol 9 ◽  
Author(s):  
Roger K. Crouch ◽  
A. L. Fripp ◽  
W. J. Debnam ◽  
R. E. Taylor ◽  
H. Groot
Keyword(s):  
Thermal Conductivity ◽  
Thermal Analysis ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Thermophysical Properties ◽  
Room Temperature ◽  
Bridgman Method ◽  
The Other ◽  
Temperature Range ◽  
Diffusivity Measurements

ABSTRACTThe thermal diffusivity of Ge has been measured over a temperature range from 300° C to 1010° C which includes values for the melt. Specific heat has been measured from room temperature to 727° C. Thermal conductivity has been calculated over the same temperature range as the diffusivity measurements. These data are reported along with the best values from the literature for the other parameters which are required to calculate the temperature and convective fields for the growth of germanium by the Bridgman method. These parameters include the specific heat, the viscosity, the emissivity, and the density as a function of temperature.

Thermodynamic Properties of Wurtzite and Zinc-Blende AlN

2013 ◽  
Vol 455 ◽  
pp. 127-130
Author(s):  
Xue Mei Cai ◽  
Jing Mei Wang ◽  
Qian Neng Zhou
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Room Temperature ◽  
Potential Method ◽  
Zinc Blende ◽  
Phonon Spectra ◽  
The Difference ◽  
Increasing Temperature ◽  
Pseudo Potential ◽  
Good Agreement

In this paper, we carry out linear response calculation to determine the phonon density of states and the thermodynamic properties of the wurtzite and zinc-blende AlN by using the norm-conserving pseudo-potential method. The optimized lattice constant is in good agreement with the available experimental data. The internal energies increase almost linearly with temperature and the phonon free energy curves move down with increasing temperature in both structures. The zero value of the lattice vibration free energy appears at temperature 707K in wurtzite and 728K in zinc-blende AlN respectively. The specific heat capacity of the wurtzite AlN is higher than that of the zinc-blende AlN at room temperature owing to the difference of the phonon spectra.

scholarly journals Особенности доменной структуры гексаферрита BaFe-=SUB=-12-=/SUB=-O-=SUB=-19-=/SUB=- вблизи температуры Кюри

2020 ◽  
Vol 62 (7) ◽  
pp. 1050
Author(s):  
А.А. Безлепкин ◽  
С.П. Кунцевич
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Domain Walls ◽  
Physical Mechanism ◽  
Structural Features ◽  
Temperature Range ◽  
The Difference ◽  
Increasing Temperature ◽  
Curie Temperature Tc ◽  
Ordered State

The structural features of the domain walls of the BaFe12O19 hexaferrite near the Curie temperature TC = 724 K were studied. The studies were performed on single-crystal samples in an alternating magnetic field with a frequency of 73 MHz and 71 MHz with a constant magnetic field in the range 0–0.25 kOe. In BaFe12O19 at a temperature of T1 = 716 K, the magnetic structure of the domain walls changes – the Bloch walls transform into linear walls with increasing temperature. The value ΔТ = Tc – T1≈8 K. The physical mechanism considered in the work, which determines the difference between the temperature range of the existence of the magnetically ordered state and the temperature range of the existence of the Bloch domain walls, is consistent with experimental results. The estimated calculation of the criterion for the transition of the Bloch domain wall to a linear wall at T1 = 716 K corresponds to the obtained experimental data.

Ultrasonic Study of Machinable Ceramic over Temperature Range from Room Temperature to 1000°C

2005 ◽  
Vol 44 (6B) ◽  
pp. 4339-4341 ◽  
Author(s):  
Nobuo Kashiwagura ◽  
Masayuki Akita ◽  
Hiroaki Kamioka
Keyword(s):  
Room Temperature ◽  
Ultrasonic Study ◽  
Temperature Range ◽  
Machinable Ceramic

scholarly journals Influence of Aging on Mechanical Properties of Yttria-Doped Zirconia

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 287-303 ◽  
Author(s):  
Yuta Kimura ◽  
Takuto Kushi ◽  
Atsushi Unemoto ◽  
Koji Amezawa ◽  
Tatsuya Kawada
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Oxygen Vacancies ◽  
Aging Treatment ◽  
Resonance Method ◽  
The Other ◽  
Shear Moduli ◽  
Local Ordering ◽  
The Difference ◽  
Increasing Temperature

We evaluated the influence of aging on mechanical properties of 8% yttria-doped zirconia (8YSZ) from room temperature to 1200 K. The temperature dependence of the dynamic Young’s and shear moduli of 8YSZ with and without the aging treatment was investigated by using a resonance method. The dynamic Young’s and shear moduli of 8YSZ without the aging treatment decreased by 33% below 700 K and gradually increased at higher temperatures with increasing temperature. On the other hand, those with the aging treatments decreased by around 20% below 600 K while did not significantly change above 600 K with increasing temperature. These demonstrated the effect of aging on the dynamic Young’s and shear moduli of 8YSZ was most remarkable at intermediate temperatures (600~1000 K). Although it was suggested that the existence ratio of the metastable tetragonal phase was increased during the aging treatment, it is likely that the influence of this phase transition on the dynamic Young’s and shear moduli was not significant. It seemed that the difference in the dynamic Young’s and shear moduli of 8YSZ with and without the aging treatment at intermediate temperatures was due to the local ordering of the oxygen vacancies.

Characteristics of Helium Diffusion Trajectory: A Molecular Dynamics Study

2013 ◽  
Author(s):  
Min Chen
Keyword(s):  
Molecular Dynamics ◽  
Helium Atom ◽  
Layered Structure ◽  
Room Temperature ◽  
The Difference ◽  
Increasing Temperature ◽  
He Atom ◽  
Helium Diffusion

Molecular dynamics (MD) are employed to explore the features of Helium atom and He clusters diffusion in titanium at the temperatures between room temperature and 667k. The results demonstrate that the frequency for Helium atom jumping from site to site increases with the increasing temperature. Another important feature is that the diffusion of a He atom and a He trimer is a layered structure. The difference is that the trajectory of a He atom is between two Ti atom layers of (001) planes, and the trajectory of a He trimer is overlapped with the Ti atom layers of (001) plane. Meanwhile, it is observed that the layered structured diffusion becomes ambiguous for a He atom and a He trimer when the temperature is increased. The conclusion emphasizes different migration features for He clusters of various sizes.

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