scholarly journals High-temperature behavior of housed piezoelectric resonators based on CTGS

2021 ◽  
Vol 10 (2) ◽  
pp. 271-279
Author(s):  
Michal Schulz ◽  
Rezvan Ghanavati ◽  
Fabian Kohler ◽  
Jürgen Wilde ◽  
Holger Fritze
Keyword(s):  
Resonance Frequency ◽  
Shear Mode ◽  
Stable Operation ◽  
Mechanical Stiffness ◽  
Temperature Changes ◽  
Resonance Behavior ◽  
Acoustic Losses ◽  
Thickness Shear

Abstract. A temperature sensor based on piezoelectric single crystals allowing stable operation in harsh environments such as extreme temperatures and highly reducing or oxidizing atmospheres is presented. The temperature dependence of the mechanical stiffness of thickness shear mode resonators is used to determine temperature changes. The sensor is based on catangasite (Ca3TaGa3Si2O14 – CTGS), a member of a langasite crystal family. CTGS exhibits an ordered crystal structure and low acoustic losses, even at 1000 ∘C. The resonance frequency and quality factor of unhoused and of housed CTGS resonators are measured up to about 1030 ∘C. A temperature coefficient of the resonance frequency of about 200 Hz K−1 for a 5 MHz device is found and enables determination of temperature changes as small as 0.04 K. Housed CTGS resonators do not show any significant change in the resonance behavior during a 30 d, long-term test at 711 ∘C.

scholarly journals Study of the Relation between the Resonance Behavior of Thickness Shear Mode (TSM) Sensors and the Mechanical Characteristics of Biofilms

Sensors ◽  
2017 ◽  
Vol 17 (6) ◽  
pp. 1395 ◽  
Author(s):  
Pedro Castro ◽  
Luis Elvira ◽  
Juan Maestre ◽  
Francisco Montero de Espinosa
Keyword(s):  
Mechanical Characteristics ◽  
Shear Mode ◽  
Thickness Shear Mode ◽  
Resonance Behavior ◽  
Thickness Shear

Determination of complex shear modulus with thickness shear mode resonators

1997 ◽  
Vol 30 (3) ◽  
pp. 346-356 ◽  
Author(s):  
Ralf Lucklum ◽  
Carsten Behling ◽  
Richard W Cernosek ◽  
Stephen J Martin
Keyword(s):  
Shear Modulus ◽  
Shear Mode ◽  
Complex Shear Modulus ◽  
Thickness Shear Mode ◽  
Complex Shear ◽  
Thickness Shear

Sensors for High-Throughput Materials Characterization: 24-channel Array of Quartz Crystal Microbalances

2003 ◽  
Vol 804 ◽  
Author(s):  
William G. Morris ◽  
Radislav A. Potyrailo
Keyword(s):  
Gas Flow ◽  
Quartz Crystal ◽  
Materials Characterization ◽  
Shear Mode ◽  
Secondary Screen ◽  
Quartz Crystal Microbalances ◽  
Chlorinated Organic ◽  
Sensor Materials

ABSTRACTWe have developed a multichannel materials characterization system based on thickness-shear mode (TSM) sensors, also known as quartz crystal microbalances (QCMs). The sensors are arranged as a 6 × 4 array that is compatible with available 24-well plates that can be manipulated with standard robotic equipment. Our sensor system can measure frequencies from 5 MHz to 20 MHz with a noise level of less than 0.1 Hz for a 1 sec acquisition interval. The sensors can be placed in a gas-flow-though cell for studies of vapor-sorption properties, or they can be immersed into a 24-well plate array for studies of materials solubility. The sensor array is connected to the measurement electronics through a multi-conductor cable, enabling the sensors to be operated in a temperature, pressure, or chemical environment, which would otherwise adversely affect the electronic stability. The 24-channel array has been applied to the screening of sensor materials for determination of chlorinated organic solvents at part per billion levels in groundwater wells. The primary screen is the discovery screen where materials are exposed to a single analyte concentration. The secondary screen is the focused evaluation where the best subset of these materials is exposed to analytes and interferences. The tertiary screen involves evaluation of material performance under conditions mimicking the long-term application. Six families of potential sensor materials were examined with rapid downselection by using this approach.

Film Conductivity Controlled Variation of the Amplitude Distribution of High-temperature Resonators

2011 ◽  
Vol 1299 ◽  
Author(s):  
Silja Schmidtchen ◽  
Denny Richter ◽  
Han Xia ◽  
Holger Fritze
Keyword(s):  
High Temperature ◽  
Direct Determination ◽  
Amplitude Distribution ◽  
Metal Electrode ◽  
Shear Mode ◽  
Mechanical Displacement ◽  
Partial Pressures ◽  
Doppler Interferometer ◽  
Thickness Shear

ABSTRACTHigh-temperature measurements of the spatial distribution of the displacement characteristics of a thickness shear mode langasite (La3Ga5SiO14) resonator are obtained using a laser Doppler interferometer. Thereby, the resonator is excited in the fundamental mode and the third overtone. Further, the resonator is coated with a gas sensitive CeO2-x film which exceeds the metal electrode. In reducing atmospheres the conductivity of the film increases and induces an increase of the effective electrode area. This effect leads to a broadening of the mechanical displacement distribution. The latter depends strongly on the size of the excited part of the resonator which is determined by the effective size of the electrodes. The direct determination of the mechanical displacement at different oxygen partial pressures confirms a model as derived from the electrical impedance of resonator devices [1]. Further, information about the mass sensitivity distribution of resonators is obtained since the property is directly proportional to the amplitude.

Preparation And elemental analysis of ancient fibers

1987 ◽  
Vol 45 ◽  
pp. 410-411
Author(s):  
Allen Angel ◽  
Kathryn A. Jakes
Keyword(s):  
Cross Sections ◽  
Physical Structure ◽  
Energy Dispersive ◽  
Archaeological Sites ◽  
X Ray ◽  
Long Term Storage ◽  
Backscattered Electron ◽  
Electron Imaging

Fabrics recovered from archaeological sites often are so badly degraded that fiber identification based on physical morphology is difficult. Although diagenetic changes may be viewed as destructive to factors necessary for the discernment of fiber information, changes occurring during any stage of a fiber's lifetime leave a record within the fiber's chemical and physical structure. These alterations may offer valuable clues to understanding the conditions of the fiber's growth, fiber preparation and fabric processing technology and conditions of burial or long term storage (1).Energy dispersive spectrometry has been reported to be suitable for determination of mordant treatment on historic fibers (2,3) and has been used to characterize metal wrapping of combination yarns (4,5). In this study, a technique is developed which provides fractured cross sections of fibers for x-ray analysis and elemental mapping. In addition, backscattered electron imaging (BSI) and energy dispersive x-ray microanalysis (EDS) are utilized to correlate elements to their distribution in fibers.

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