A new developed velocity of sound measurement device for characterization of multi-component gas mixtures under elevated temperatures and pressures

2014 ◽  
Vol 85 (7) ◽  
pp. 075001 ◽  
Author(s):  
C. Seibel ◽  
J. Suedmeyer ◽  
T. M. Fieback
Keyword(s):  
Elevated Temperatures ◽  
Gas Mixtures ◽  
Velocity Of Sound ◽  
Measurement Device ◽  
Sound Measurement

324 Naturalistic Characterization of Sleep in Chronic Insomnia Using a Non-Contact Sleep Measurement Device

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A130-A130
Author(s):  
Devon Hansen ◽  
Mary Peterson ◽  
Roy Raymann ◽  
Hans Van Dongen ◽  
Nathaniel Watson
Keyword(s):  
Sleep Onset ◽  
Contact Device ◽  
Chronic Insomnia ◽  
Poor Sleep ◽  
Measurement Device ◽  
Home Setting ◽  
Time In Bed ◽  
Sleep Measurement ◽  
Measurement Devices

Abstract Introduction Individuals with insomnia report poor sleep quality and non-restorative sleep, and often exhibit irregular sleep patterns over days and weeks. First night effects and logistical challenges make it difficult to measure these sleep characteristics in the laboratory. Also, sensitivity to sleep disruption from obtrusive measurement devices confounds sleep measurements in people with insomnia in their naturalistic setting. Non-contact sleep measurement devices have the potential to address these issues and enable ecologically valid, longitudinal characterization of sleep in individuals with insomnia. Here we use a non-contact device – the SleepScore Max (SleepScore Labs) – to assess the sleep of individuals with chronic insomnia, compared to healthy sleeper controls, in their home setting. Methods As part of a larger study, 13 individuals with chronic insomnia (ages 25-60y, 7 males) and 8 healthy sleeper controls (ages 21-46y, 6 females) participated in an at-home sleep monitoring study. Enrollment criteria included an age range of 18-65y and, for the insomnia group, ICSD-3 criteria for chronic insomnia with no other clinically relevant illness. Participants used the non-contact sleep measurement device to record their sleep periods each night for 8 weeks. Sleep measurements were analyzed for group differences in both means (characterizing sleep overall) and within-subject standard deviations (characterizing sleep variability across nights), using mixed-effects regression controlling for systematic between-subject differences. Results Based on the non-contact sleep measurements, individuals with chronic insomnia exhibited greater variability in bedtime, time in bed, total sleep time, sleep latency, total wake time across time in bed, wakefulness after sleep onset, sleep interruptions, and estimated light sleep, compared to healthy sleeper controls (all F>5.7, P<0.05). No significant differences were found for group averages and for variability in estimated deep and REM sleep. Conclusion In this group of individuals with chronic insomnia, a non-contact device used to characterize sleep naturalistically captured enhanced variability across nights in multiple aspects of sleep stereotypical of sleep disturbances in chronic insomnia, differentiating the sample statistically significantly from healthy sleeper controls. Support (if any) NIH grant KL2TR002317; research devices provided by SleepScore Labs.

In-Situ Characterization of Growth and Intermixing at a Heteroepitaxial Interface: Fe on Au(001)

1993 ◽  
Vol 318 ◽  
Author(s):  
Q. Jiang ◽  
A. Chan ◽  
Y.-L. He ◽  
G.-C. Wang
Keyword(s):  
Elevated Temperatures ◽  
Chemical Elements ◽  
Background Intensity ◽  
In Situ Characterization ◽  
Initial Stage ◽  
Monolayer Growth ◽  
Low Energy Electron ◽  
Energy Dependent

ABSTRACTThe growth and chemical intermixing of submonolayer and a few monolayer thick Fe films on a Au(001) surface was studied by High Resolution Low Energy Electron Diffraction (HRLEED) technique. Through the analysis of the energy dependent angular profiles as a function of time, we obtained the distribution of islands and distribution of spacings during submonolayer growth. The interference of electron waves from different chemical elements in terraces at different heights in the surface contributes to the background intensity and broadening in the angular profiles of diffraction beams. A subsurface Fe capped by Au islands as a result of atomic place exchange was observed at the initial stage of monolayer growth. From the energy dependent angular profiles as a function of temperature, we determine the quantitative change of inhomogeneity length (∼20 Å) at the interface of ultrathin films at elevated temperatures due to intermixing.

The High Temperature Deformation Behavior of A Cr2Nb Ordered Intermetallic System

1990 ◽  
Vol 213 ◽  
Author(s):  
G. E. Vignoul ◽  
J.M. Sanchez ◽  
J. K. Tien
Keyword(s):  
Deformation Behavior ◽  
Elevated Temperatures ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Deformation Law ◽  
Ordered Intermetallic ◽  
Intermetallic System ◽  
Increasing Temperature ◽  
Stress Term

ABSTRACTA basic characterization of the deformation behavior of Cr2Nb by microindention at ambient and elevated temperatures (up to 1400 °C) was undertaken. The microhardness of this system was seen to decrease with increasing temperature, from 1040 MPa at 25°C to 322 MPa at 1400 °C. Further, the microindention creep behavior of this system was studied by varying time on load at T = 1000 and 1200°C. Analysis of the data showed that m = 24 and Qapp = 477.61 kJ/mole. These unusually high values are indicative of the existence of an effective resisting stress against creep. When the data was fit against a microindention creep deformation law which was modified to incorporate an effective resisting stress term, it was determined that m = 4.5, Qcreep = 357 kJ/mole and the resisting stress term σr = 300 MPa.

Characterization of Wafer-Level Au-In-Bonded Samples at Elevated Temperatures

2015 ◽  
Vol 46 (6) ◽  
pp. 2637-2645 ◽  
Author(s):  
Thi-Thuy Luu ◽  
Nils Hoivik ◽  
Kaiying Wang ◽  
Knut E. Aasmundtveit ◽  
Astrid-Sofie B. Vardøy
Keyword(s):  
Elevated Temperatures ◽  
Wafer Level

Measurement of the Material State Including the Effects of Recovery and Recrystallization

2000 ◽  
Author(s):  
M. E. Bange ◽  
A. J. Beaudoin ◽  
M. G. Stout ◽  
S. R. MacEwen
Keyword(s):  
Elevated Temperatures ◽  
High Strain ◽  
Quantitative Measure ◽  
Experimental Program ◽  
Strain Rates ◽  
Compression Tests ◽  
State Variable ◽  
Mechanical Threshold ◽  
Material State

Abstract Deformation at elevated temperatures in combination with high strain rates leads to recovery and recrystallization in aluminum alloys. Previous work in recrystallization has emphasized the detailing of microstructural trend in progression from the deformed to the annealed state. In the following, we examine the effect of rate dependence on deformation on AA 5182 and AA 6061. It is demonstrated that identification of underlying microstructural mechanisms is critical. An experimental program is then outlined for characterization of recovery and recrystallization of AA 5182. Instantaneous hardening rate and flow stress are developed from interrupted compression tests. These data are used to establish a quantitative measure of recovery through evaluation of a state variable for work hardening, the mechanical threshold. It is intended that the results serve as a foundation for development of relations for evolution of a mechanical state variable in the presence of recrystallization. Such a framework is necessary for the practical prediction of interstand recrystallization in hot rolling operations.

Enhancing the Thermal and Mechanical Characteristics of Polyvinyl Alcohol (PVA)-Hemp Protein Particles (HPP) Composites

2021 ◽  
Vol 36 (2) ◽  
pp. 137-143
Author(s):  
S. A. Awad
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperatures ◽  
Composite Films ◽  
Tensile Tests ◽  
Mechanical Analysis ◽  
Decomposition Temperature ◽  
Scanning Calorimetry ◽  
Solution Casting Method ◽  
Protein Particles

Abstract This paper aims to describe the thermal, mechanical, and surface properties of a PVA/HPP blend whereby the film was prepared using a solution casting method. The improvements in thermal and mechanical properties of HPP-based PVA composites were investigated. The characterization of pure PVA and PVA composite films included tensile tests, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). The results of TGA and DSC indicated that the addition of HPP increased the thermal decomposition temperature of the composites. Mechanical properties are significantly improved in PVA/HPP composites. The thermal stability of the PVA composite increased with the increase of HPP filler content. The tensile strength increased from 15.74 ± 0.72 MPa to 27.54 ± 0.45 MPa and the Young’s modulus increased from 282.51 ± 20.56 MPa to 988.69 ± 42.64 MPa for the 12 wt% HPP doped sample. Dynamic mechanical analysis (DMA) revealed that at elevated temperatures, enhanced mechanical properties because of the presence of HPP was even more noticeable. Morphological observations displayed no signs of agglomeration of HPP fillers even in composites with high HPP loading.

Mechanical Property and Oxidation Behavior of LPS-SiC Materials

2006 ◽  
Vol 321-323 ◽  
pp. 913-916
Author(s):  
Sang Ll Lee ◽  
Yun Seok Shin ◽  
Jin Kyung Lee ◽  
Jong Baek Lee ◽  
Jun Young Park
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
Oxidation Behavior ◽  
Elevated Temperatures ◽  
Indentation Test ◽  
Bending Test ◽  
Secondary Phases ◽  
Three Point Bending ◽  
Different Temperatures

The microstructure and the mechanical property of liquid phase sintered (LPS) SiC materials with oxide secondary phases have been investigated. The strength variation of LPS-SiC materials exposed at the elevated temperatures has been also examined. LPS-SiC materials were sintered at the different temperatures using two types of Al2O3/Y2O3 compositional ratio. The characterization of LPS-SiC materials was investigated by means of SEM with EDS, three point bending test and indentation test. The LPS-SiC material with a density of about 3.2 Mg/m3 represented a flexural strength of about 800 MPa and a fracture toughness of about 9.0 MPa⋅√m.

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