scholarly journals Optimization of SAW Devices with LGS/Pt Structure for Sensing Temperature

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2441
Author(s):  
Xueling Li ◽  
Wen Wang ◽  
Shuyao Fan ◽  
Yining Yin ◽  
Yana Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Quality Factor ◽  
Short Pulse ◽  
Extreme Temperature ◽  
Parameters Optimization ◽  
Design Parameters ◽  
Q Value ◽  
Element Analysis ◽  
Saw Devices ◽  
Extreme High Temperature

Research has shown that SAW (surface acoustic wave) devices with an LGS/Pt (langasite La3Ga5SiO14/platinum) structure are useful in high-temperature sensor applications. Extreme high temperature brings great acoustic attenuation because of the thermal radiation loss, which requires that the sensing device offer a sufficiently high quality factor (Q) and a low loss. Therefore, it is necessary to improve the performance of the quality factor as much as possible so as to better meet the application of high-temperature sensors. Based on these reasons, the main work of this paper was to extract accurate simulation parameters to optimize the Pt/LGS device and obtain Q-value device parameters. Optimization of SAW devices with LGS/Pt structure for sensing extreme high temperature was addressed by employing a typical coupling of modes (COM) model in this work. Using the short pulse method, the reflection coefficient of Pt electrodes on LGS substrate was extracted accurately by characterizing the prepared SAW device with strategic design. Other relevant parameters for COM simulation were determined by finite element analysis. To determine the optimal design parameters, the COM simulation was conducted on the SAW sensing device with a one-port resonator pattern for sensing extreme temperature, which allows for a larger Q-value and low insertion loss. Experimental results validate the theoretical simulation. In addition, the corresponding high-temperature characteristics of the prepared sensing device were investigated.

scholarly journals The association between extreme temperature and pulmonary tuberculosis in Shandong Province, China, 2005–2016: a mixed method evaluation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Dongzhen Chen ◽  
Hua Lu ◽  
Shengyang Zhang ◽  
Jia Yin ◽  
Xuena Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Pulmonary Tuberculosis ◽  
Incidence Rate ◽  
Meta Analysis ◽  
Extreme Temperature ◽  
Shandong Province ◽  
Effect Model ◽  
Extreme High Temperature ◽  
The Relationship

Abstract Background The effects of extreme temperature on infectious diseases are complex and far-reaching. There are few studies to access the relationship of pulmonary tuberculosis (PTB) with extreme temperature. The study aimed to identify whether there was association between extreme temperature and the reported morbidity of PTB in Shandong Province, China, from 2005 to 2016. Methods A generalized additive model (GAM) was firstly conducted to evaluate the relationship between daily reported incidence rate of PTB and extreme temperature events in the prefecture-level cities. Then, the effect estimates were pooled using meta-analysis at the provincial level. The fixed-effect model or random-effect model was selected based on the result of heterogeneity test. Results Among the 446,016 PTB reported cases, the majority of reported cases occurred in spring. The higher reported incidence rate areas were located in Liaocheng, Taian, Linyi and Heze. Extreme low temperature had an impact on the reported incidence of PTB in only one prefecture-level city, i.e., Binzhou (RR = 0.903, 95% CI: 0.817–0.999). While, extreme high temperature was found to have a positive effect on reported morbidity of PTB in Binzhou (RR = 0.924, 95% CI: 0.856–0.997) and Weihai (RR = 0.910, 95% CI: 0.843–0.982). Meta-analysis showed that extreme high temperature was associated with a decreased risk of PTB (RR = 0.982, 95% CI: 0.966–0.998). However, extreme low temperature was no relationship with the reported incidence of PTB. Conclusion Our findings are suggested that extreme high temperature has significantly decreased the risk of PTB at the provincial levels. The findings have implications for developing strategies to response to climate change.

Analysis of Extreme Temperature Events in North China Based on EMD Method

2013 ◽  
Vol 295-298 ◽  
pp. 854-858 ◽  
Author(s):  
Xiao Ying Chen ◽  
Yi Min Zhu ◽  
Lin Lin Xia ◽  
Wei Xing Zhang
Keyword(s):  
High Temperature ◽  
Temperature Variation ◽  
North China ◽  
Southern Oscillation ◽  
Extreme Temperature ◽  
Temporal Variations ◽  
Mode Decomposition ◽  
Extreme High Temperature ◽  
Spatio Temporal ◽  
Emd Method

The spatio-temporal variations of extreme temperature in North China during 1954-2008 are analyzed based on Empirical Mode Decomposition (EMD) method. The results show that the interannual-to-interdecadal variabilities of extreme temperature in North China. 3-4 years and 7-8 years interannual variabilities as well as a decreasing trend are dominant while 15 years oscillation takes second place in the extreme low temperature variation. Meanwhile, 3-4 year interannual variabilities are dominant while 6-7 years, 14-15 years 40 years oscillation as well as an increasing trend takes second place in the extreme high temperature variation. 3-4 years interannual variabilities of both extreme low and high temperature are closely related to El Nino-Southern Oscillation (ENSO), while interdecadal variabilities and trend of extreme temperature are obviously associated with the Pacific Decadal Oscillation (PDO). Besides, PDO plays an important role on interdecadal modulation of interannual to decadal variabilities of extreme temperature in North China.

2D Geometrical Parameters Optimization Design Method of CMC/Metal Dovetail Joint

2018 ◽  
Vol 923 ◽  
pp. 156-163
Author(s):  
Tian Yuan Yang ◽  
Duo Qi Shi ◽  
Zhen Cheng
Keyword(s):  
Optimization Design ◽  
Design Method ◽  
Optimization Methods ◽  
Parametric Modeling ◽  
Parameters Optimization ◽  
Design Parameters ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Whole Process ◽  
Parameter Optimization Design

This paper establishes a 2D geometrical parameter optimization design method of CMC/metal dovetail joint by using ABAQUS and ISIGHT. Firstly, use the ABAQUS script to finish the 2D geometric parametric modeling and the whole process of the finite element analysis of the simplified dovetail joint in the Python language. Then use ISIGHT software to optimize the 2D geometrical parameters. Finally, compare the optimization results of different optimization methods and get the optimal design parameters. This method is really efficient for the preliminary 2D design of the CMC/metal dovetail.

scholarly journals Optimization of AIN Composite Structure Based Surface Acoustic Wave Device for Potential Sensing at Extremely High Temperature

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4160
Author(s):  
Shuyao Fan ◽  
Wen Wang ◽  
Xueling Li ◽  
Yana Jia ◽  
Yuan Sun ◽  
...  
Keyword(s):  
High Temperature ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Composite Structure ◽  
Wave Mode ◽  
Design Parameters ◽  
Extreme High Temperature ◽  
Spurious Mode ◽  
The One ◽  
Simulation Parameters

A surface acoustic wave (SAW) device with an aluminum nitride (AlN) composite structure of Al2O3/IDTs/AlN/Metal/Si was proposed for sensing at extreme high-temperature in this work. Optimization allowing determination of optimal design parameters for SAW devices was conducted using the typical coupling of modes (COM) model. The SAW propagation characteristics in the layered structure were investigated theoretically by employing the finite element method (FEM). Multiple acoustic-wave modes that occurred in the AlN composite structure was analyzed, and the corresponding suppression of spurious mode was proposed. The COM simulation parameters corresponding to the effective acoustic-wave mode were extracted, and the optimized parameters of the one–port SAW resonator with a high-quality factor were determined.

Modeling of Failure in Aluminum Alloy Braze for a High Temperature Thermoelectric Assembly

2013 ◽  
Vol 2013 (1) ◽  
pp. 000957-000963
Author(s):  
S. Arifeen ◽  
G. Potirniche ◽  
A. Elshabini ◽  
F. Barlow
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Damage Mechanics ◽  
Low Cycle Fatigue ◽  
Three Dimensional ◽  
Extreme Temperature ◽  
Continuum Damage Mechanics ◽  
Extreme Environment ◽  
Element Analysis ◽  
Die Attach

The objective of this work is to design a commercially viable thermoelectric generator (TEG) assembly that can be used in passenger vehicles to be able to withstand extreme environmental conditions. Since the operating temperatures of the TEGs can reach temperature levels higher than 500 °C, aluminum braze alloys offer a good high temperature solution for die attach. However, the evolution of fatigue damage in the aluminum braze must be understood in order to ensure an acceptable reliability of the TEG. In this paper, the proposed design of TEG package assembly was evaluated under extreme temperature conditions. Three-dimensional models of full scale TEG were analyzed using finite element analysis (FEA). The failures of aluminum alloy based braze (high temperature form of solder) material in the TEG application was investigated. Low cycle fatigue using direct cyclic approach was considered for the reliability analysis. Continuum damage mechanics approach was used to study the fatigue failure due to power cycling. Different TEG assembly designs were investigated and compared to determine the best possible solution for the extreme environment application.

A Simplified Design Model for Modular Steel Buildings Subject to Vapor Cloud Explosions (VCEs)

2020 ◽  
Vol 14 ◽  
Author(s):  
Osama Bedair
Keyword(s):  
Dynamic Response ◽  
Minimum Cost ◽  
Design Parameters ◽  
Front Wall ◽  
Steel Buildings ◽  
Element Analysis ◽  
Analysis And Design ◽  
Vapor Cloud ◽  
Building Components ◽  
Analytical Expressions

Background: Modular steel buildings (MSB) are extensively used in petrochemical plants and refineries. Limited guidelines are available in the industry for analysis and design of (MSB) subject to accidental vapor cloud explosions (VCEs). Objectives: The paper presents simplified engineering model for modular steel buildings (MSB) subject to accidental vapor cloud explosions (VCEs) that are extensively used in petrochemical plants and refineries. Method: A Single degree of freedom (SDOF) dynamic model is utilized to simulate the dynamic response of primary building components. Analytical expressions are then provided to compute the dynamic load factors (DLF) for critical building elements. Recommended foundation systems are also proposed to install the modular building with minimum cost. Results: Numerical results are presented to illustrate the dynamic response of (MSB) subject to blast loading. It is shown that (DLF)=1.6 is attained at (td/t)=0.4 for front wall (W1) with (td/T)=1.25. For side walls (DLF)=1.41 and is attained at (td/t)=0.6. Conclusions: The paper presented simplified tools for analysis and design of (MSB) subject accidental vapor cloud blast explosions (VCEs). The analytical expressions can be utilized by practitioners to compute the (MSB) response and identify the design parameters. They are simple to use compared to Finite Element Analysis.

scholarly journals Evaluation on the Bond Capacity of the Fire-Protected FRP Bonded to Concrete Under High Temperature

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Soo-yeon Seo ◽  
Jong-wook Lim ◽  
Su-hyun Jeong
Keyword(s):  
High Temperature ◽  
Critical Temperature ◽  
Temperature Variation ◽  
Fire Resistance ◽  
Fire Protection ◽  
Element Analysis ◽  
External Temperature ◽  
Near Surface ◽  
Board Type ◽  
The Face

AbstractTo figure out the change in the reinforcing effect of FRP system used for the retrofit of RC beam when it is exposed to high temperature, it is required to evaluate not only the behavior of the entire beam, but also the bond performance at anchorage zone through a bond test according to the increase of external temperature. Moreover, the study to find various fire-protection methods is necessary to prevent the epoxy from reaching the critical temperature during an exposure to high temperature. In this manner, the fire-resistance performances of externally bonded (EB) FRP and near-surface-mounted (NSM) FRP to concrete block were evaluated by high-temperature exposure tests after performing a fire-protection on the surface in this paper. Board-type insulation with mortar was considered for the fire-protection of FRP system. After the fire-protection of the FRPs bonded to concrete blocks, an increasing exposure temperature was applied to the specimens with keeping a constant shear bond stress between concrete and the FRP. Based on the result, the temperature when the bond strength of the FRP disappears was evaluated. In addition, a finite element analysis was performed to find a proper method for predicting the temperature variation of the epoxy which is fire-protected with board-type insulation during the increase of external temperature. As a result of the test, despite the same fire-protection, NSM specimens were able to resist 1.54–2.08 times higher temperature than EB specimens. In the design of fire-protection of FRP system with the board-type insulation, it is necessary to consider the transfer from sides as well as the face with FRP. If there is no insulation of FP boards on the sides, the epoxy easily reaches its critical temperature by the heat penetrated to the sides, and increasing the thickness of the FP board alone for the face with FRP does not increase the fire-resistance capacity. As a result of the FE analysis, the temperature variation at epoxy can be predicted using the analytical approach with the proper thermal properties of FP mortar and board.

Analysis of a Tubular Linear Permanent Magnet Motor for Reciprocating Compressor Applications

2013 ◽  
Vol 448-453 ◽  
pp. 2114-2119 ◽  
Author(s):  
Izzeldin Idris Abdalla ◽  
Taib Ibrahim ◽  
Nursyarizal Mohd Nor
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Outer Radius ◽  
Design Parameters ◽  
Reciprocating Compressor ◽  
Permanent Magnet Motors ◽  
Permanent Magnet Motor ◽  
Element Analysis ◽  
Split Ratio ◽  
Single Coil

This paper describes a design optimization to achieve optimal performance of a two novel single-phase short-stroke tubular linear permanent magnet motors (TLPMMs) with rectangular and trapezoidal permanent magnets (PMs) structures. The motors equipped with a quasi-Halbach magnetized moving-magnet armature and slotted stator with a single-slot carrying a single coil. The motors have been developed for reciprocating compressor applications such as household refrigerators. It is observed that the TLPMM efficiency can be optimized with respect to the leading design parameters (dimensional ratios). Furthermore, the influence of mover back iron is investigated and the loss of the motor is computed. Finite element analysis (FEA) is employed for the optimization, and the optimal values of the ratio of the axial length of the radially magnetized magnets to the pole pitch as well as the ratio of the PMs outer radius-to-stator outer radius (split ratio), are identified.

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