scholarly journals Setup of high resolution thermal expansion measurements in closed cycle cryostats using capacitive dilatometers

2021 ◽  
Author(s):  
Neeraj Kumar Rajak ◽  
Neha Kondedan ◽  
Husna Jan ◽  
Muhammed Dilshah U ◽  
Navya S. D. ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Resolution ◽  
High Temperature Superconductors ◽  
Linear Thermal Expansion ◽  
Measurement Data ◽  
Relative Sensitivity ◽  
Published Data ◽  
Closed Cycle ◽  
Noise Mitigation ◽  
Thermal Expansion Data

Abstract We present high resolution thermal expansion measurement data obtained with high relative sensitivity of ΔL/L = 10-9 and accuracy of ±2% using closed cycle refrigerators employing two different dilatometers. Experimental details of the set-up utilizing the multi-function probe integrated with the cold head of two kinds of closed cycle refrigerators, namely, pulse tube and Gifford-McMahon cryocoolers, has been described in detail. The design consists of decoupling the bottom sample puck and taking connections from the top of the multi-function probe to mitigate the vibrational noise arising from the cold heads, using which smooth and high quality thermal expansion data could be obtained. It was found that dilatometer #2 performs a better noise mitigation than dilatometer #1 due to the constrained movement of the spring in dilatometer #2. This was confirmed by finite element method simulations that were performed for understanding the spring movement in each dilatometer using which the effect of different forces/pressures and vibrations on the displacement of the spring was studied. Linear thermal expansion coefficient α obtained using both dilatometers was evaluated using derivative of a polynomial fit. The resultant α obtained using dilatometer #2 and either of the closed cycle cryostats on standard metals silver and aluminium showed excellent match with published values obtained using wet cryostats. Finally, thermal expansion measurements is reported on single crystals of two high temperature superconductors YBa2Cu3-xAlxO6+δ and Bi2Sr2CaCu2O8+x along the c-axis with very good match found with published data obtained earlier using wet liquid helium based cryostats.

Calculation of Defect Formation Energy from the Thermal Expansion Data for Lead Fluoride

1994 ◽  
Vol 369 ◽  
Author(s):  
Brenda J. Schuler ◽  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Formation Energy ◽  
Defect Formation ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Lead Fluoride ◽  
Defect Formation Energy ◽  
Thermal Expansion Data

AbstractLead fluoride is a superionic conductor with the fluorite structure. Results of the measurement of linear thermal expansion of lead fluoride (reported earlier in literature) showed a large increase in the thermal expansion coefficient near 700 K where the ionic conductivity has been shown to exhibit a sharp increase. It is believed that thermally-generated defects in a crystal lattice affect the thermal expansion coefficient. This idea was applied in the present analysis to calculate the defect formation energy (Ef) by using the literature values of the coefficient of thermal expansion. It was assumed that the thermal expansion in excess of that produced due to the lattice anharmonicity (δ∝) is proportional to the concentration of defects (n). With this assumption, one may write: δ∝ = c nº exp(-Ef/kT), where c is a constant. For lead fluoride, a plot of ln(δ∝) versus (l/T) yielded Ef = 0.56 eV which is lower than the literature values. The assumptions in this analysis and the discrepancy in the result are discussed.

scholarly journals Data-Driven Intelligent 3D Surface Measurement in Smart Manufacturing: Review and Outlook

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 13
Author(s):  
Yuhang Yang ◽  
Zhiqiao Dong ◽  
Yuquan Meng ◽  
Chenhui Shao
Keyword(s):  
High Resolution ◽  
High Performance ◽  
Sampling Design ◽  
Three Dimensional ◽  
Measurement Data ◽  
Data Driven ◽  
Surface Measurement ◽  
Smart Manufacturing ◽  
Future Research ◽  
3D Surface

High-fidelity characterization and effective monitoring of spatial and spatiotemporal processes are crucial for high-performance quality control of many manufacturing processes and systems in the era of smart manufacturing. Although the recent development in measurement technologies has made it possible to acquire high-resolution three-dimensional (3D) surface measurement data, it is generally expensive and time-consuming to use such technologies in real-world production settings. Data-driven approaches that stem from statistics and machine learning can potentially enable intelligent, cost-effective surface measurement and thus allow manufacturers to use high-resolution surface data for better decision-making without introducing substantial production cost induced by data acquisition. Among these methods, spatial and spatiotemporal interpolation techniques can draw inferences about unmeasured locations on a surface using the measurement of other locations, thus decreasing the measurement cost and time. However, interpolation methods are very sensitive to the availability of measurement data, and their performances largely depend on the measurement scheme or the sampling design, i.e., how to allocate measurement efforts. As such, sampling design is considered to be another important field that enables intelligent surface measurement. This paper reviews and summarizes the state-of-the-art research in interpolation and sampling design for surface measurement in varied manufacturing applications. Research gaps and future research directions are also identified and can serve as a fundamental guideline to industrial practitioners and researchers for future studies in these areas.

Transformation behavior of yttria stabilized tetragonal zirconia polycrystal–TiB2 composites

2001 ◽  
Vol 16 (7) ◽  
pp. 2158-2169 ◽  
Author(s):  
B. Basu ◽  
J. Vleugels ◽  
O. Van Der Biest
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Low Temperature ◽  
Tetragonal Zirconia ◽  
Mechanical Analysis ◽  
Transformation Behavior ◽  
Thermal Expansion Data ◽  
Thermally Induced ◽  
First Time ◽  
Tetragonal Zirconia Polycrystal

The objective of the present article is to study the influence of TiB2 addition on the transformation behavior of yttria stabilized tetragonal zirconia polycrystals (Y-TZP). A range of TZP(Y)–TiB2 composites with different zirconia starting powder grades and TiB2 phase contents (up to 50 vol%) were processed by the hot-pressing route. Thermal expansion data, as obtained by thermo-mechanical analysis were used to assess the ZrO2 phase transformation in the composites. The thermal expansion hysteresis of the transformable ceramics provides information concerning the transformation behavior in the temperature range of the martensitic transformation and the low-temperature degradation. Furthermore, the transformation behavior and susceptibility to low-temperature degradation during thermal cycling were characterized in terms of the overall amount and distribution of the yttria stabilizer, zirconia grain size, possible dissolution of TiB2 phase, and the amount of residual stress generated in the Y-TZP matrix due to the addition of titanium diboride particles. For the first time, it is demonstrated in the present work that the thermally induced phase transformation of tetragonal zirconia in the Y-TZP composites can be controlled by the intentional addition of the monoclinic zirconia particles into the 3Y-TZP matrix.

Anomalous thermal expansion behaviors of wood under dry and low-temperature conditions

Holzforschung ◽  
2014 ◽  
Vol 68 (5) ◽  
pp. 567-574 ◽  
Author(s):  
Tsunehisa Miki ◽  
Hiroyuki Sugimoto ◽  
Yuzo Furuta ◽  
Ichinori Shigematsu ◽  
Kozo Kanayama
Keyword(s):  
Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Longitudinal Direction ◽  
Mechanical Analysis ◽  
Solid Wood ◽  
Compression Pressure ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Dry Conditions ◽  
Anomalous Thermal Expansion

Abstract The thermal expansion behavior of dry solid wood was investigated by dynamic dilatometry and thermal mechanical analysis. Anomalous thermal expansion behavior was observed concerning the displacement change under a constant compression pressure, which was not previously reported. Wood submitted to temperatures below 0°C under dry conditions exhibited a large increment in the linear thermal expansion coefficient (CLTE) and a sudden drop in the CLTE around 50°C as well as above 130°C during heating. In subsequent cooling/heating processes, these anomalous behaviors remained at temperatures below 100°C, although less pronounced, and disappeared at temperatures above 100°C. These behaviors were clearly perceptible in the radial and tangential directions but not in the longitudinal direction. The CLTE depended strongly on the heat and moisture history of the samples and the effects are species-specific.

Novel Silicon-Elastomers for Advanced Soft Lithography

2006 ◽  
Vol 947 ◽  
Author(s):  
Kyung Choi
Keyword(s):  
Thermal Expansion ◽  
High Resolution ◽  
Soft Lithography ◽  
Materials Properties ◽  
Nano Scale ◽  
Thermal Expansion Coefficients ◽  
High Thermal Expansion ◽  
Expansion Coefficients

ABSTRACTHigh resolution pattern transfers in the nano-scale regime have been considerable challenges in ‘soft lithography’ to achieve nanodevices with enhanced performances. In this technology, the resolution of pattern integrations is significantly rely on the materials' properties of polydimethylsiloxane (PDMS) stamps. Since commercial PDMS stamps have shown limitations in nano-scale resolution soft lithography due to their low physical toughness and high thermal expansion coefficients, we developed stiffer, photocured PDMS silicon elastomers designed, specifically for nano-sized soft lithography and photopatternable nanofabrications.

Analysis of Thermal Variation of Length and Refractive Index of Lead Fluoride to Study its Optical Properties

1989 ◽  
Vol 172 ◽  
Author(s):  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day
Keyword(s):  
Refractive Index ◽  
Room Temperature ◽  
Linear Thermal Expansion ◽  
Small Variation ◽  
Published Data ◽  
Thermal Variation ◽  
Lead Fluoride ◽  
Superionic Phase Transition ◽  
Lorenz Relation ◽  
Good Agreement

AbstractLinear thermal expansion and refractive index variation have been measured in lead fluoride with a laser interferometer as a function of temperature. Data has been analyzed using the Lorentz-Lorenz relation. Molecular polarizability, band gap, variation of refractive index with density, and strain-polarizability parameter have been studied as a function of temperature. They exhibit a small variation with temperature except near the superionic phase transition where the variation appears to be more pronounced. The results are in good agreement with the published data near room temperature.

scholarly journals Thermal Expansion and Electro-Elastic Features of Ba2TiSi2O8 High Temperature Piezoelectric Crystal

Crystals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 11 ◽  
Author(s):  
Chao Jiang ◽  
Feifei Chen ◽  
Fapeng Yu ◽  
Shiwei Tian ◽  
Xiufeng Cheng ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Elastic Properties ◽  
Piezoelectric Coefficient ◽  
Linear Thermal Expansion ◽  
Temperature Stability ◽  
Promising Candidate ◽  
Temperature Range ◽  
Sensor Applications ◽  
High Temperature Sensor

A high-quality Ba2TiSi2O8 (BTS) single crystal was grown using the Czochralski (Cz) pulling method. The thermal expansion and electro-elastic properties of BTS crystal were studied for high temperature sensor applications. The relative dielectric permittivities ε 11 T / ε 0 and ε 33 T / ε 0 were determined to be 16.3 and 11.8, while the piezoelectric coefficients d15, d31, d33 were found to be 17.8, 2.9, and 4.0 pC/N, respectively. Temperature dependence of electro-elastic properties were investigated, where the variation of elastic compliance s 55 E (= s 44 E ) was found to be <6% over temperature range of 20–700 °C. Taking advantage of the anisotropic thermal expansion, linear thermal expansion comparable to insulating alumina ceramic was achieved over temperature range up to 650 °C. The optimum crystal cut with large effective piezoelectric coefficient (>8.5 pC/N) and linear thermal expansion coefficient (8.03 ppm/°C) achieved for BTS crystal along the (47°, φ) direction (φ is arbitrary in 0–360°), together with its good temperature stability up to 650 °C, make BTS crystal a promising candidate for high temperature piezoelectric sensors.

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