High-Temperature Dielectric Properties Measurements of Ceramics

1992 ◽  
Vol 269 ◽  
Author(s):  
Shane Bringhurst ◽  
Octavio M. Andrade ◽  
Magdy F. Iskander
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Frequency Band ◽  
Perturbation Technique ◽  
Measurement Techniques ◽  
Coaxial Line ◽  
Experimental Results ◽  
Experimental Measurements ◽  
Insulating Materials ◽  
Made In

ABSTRACTThis paper dicusses experimental arrangements, describes measurement techniques and presents experimental results for hightemperature broadband dielectric properties measurements of ceramics. The cavity perturbation technique and the open-ended coaxial line method are used in these experimental measurements. The design and construction details of cavities and probes are described and representative results of measurements on zirconia and alumina samples (green and sintered) are presented. Results of measurements made on insulating materials are shown. In general measurements are made in the frequency band 1 to 10 GHz and temperatures up to 1000°C.

A Theoretical and Experimental Investigation of a Gas Operated Bearing Damper for Turbomachinery: Part II — Experimental Results and Comparison With Theory

1993 ◽  
Author(s):  
Padmanabhan Sundararajan ◽  
John M. Vance
Keyword(s):  
Experimental Investigation ◽  
High Temperature ◽  
Theoretical Model ◽  
Natural Frequency ◽  
Experimental Results ◽  
Experimental Measurements ◽  
Vibration Damper ◽  
Theoretical Predictions ◽  
Present Design ◽  
Gas Damper

Abstract This is the second of two papers describing results of a research project directed at developing a gas operated vibration damper for high temperature turbomachinery applications. This part presents the experimental measurements made on three variations of the gas damper hardware and compares them with the theoretical predictions presented in Part I. It is found that the isentropic theoretical model predicts the damper characteristics quite well. A maximum damping of 13.2 Ib-s/in was measured for a single actuator at a natural frequency of 100 hz using the present design and the results suggest that significantly higher damping levels are possible with design modifications.

A Gas-Operated Bearing Damper for Turbomachinery—Theoretical Predictions Versus Experimental Measurements: Part II—Experimental Results and Comparison With Theory

1995 ◽  
Vol 117 (4) ◽  
pp. 750-756 ◽  
Author(s):  
P. Sundararajan ◽  
J. M. Vance
Keyword(s):  
High Temperature ◽  
Theoretical Model ◽  
Natural Frequency ◽  
Experimental Results ◽  
Experimental Measurements ◽  
Vibration Damper ◽  
Research Project ◽  
Theoretical Predictions ◽  
Present Design ◽  
Gas Damper

This is the second of two papers describing results of a research project directed at developing a gas-operated vibration damper for high-temperature turbomachinery applications. This part presents the experimental measurements made on a gas damper hardware and compares them with the theoretical predictions given in Part I. It is found that the isentropic theoretical model predicts the damper characteristics quite well. A maximum damping of 2310 N-s/m (13.2 lb-s/in.) was measured at a natural frequency of 118 Hz using the present design and the results suggest that significantly higher damping levels are possible with design modifications.

High Temperature Broadband Dielectric Properties Measurement Techniques

1992 ◽  
Vol 269 ◽  
Author(s):  
Octavio M. Andrade ◽  
Magdy F. Iskander ◽  
Shane Bringhurst
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Measurement Techniques ◽  
Frequency Range ◽  
University Of Utah ◽  
Microwave Characterization ◽  
Characterization Of Materials ◽  
The University

ABSTRACTThis paper discusses theoretical and practical aspects of the development and implementation of various measurement techniques for high-temperature broadband microwave characterization of materials at the University of Utah. Objectives include materials measurements in the frequency range from 45 MHz to 12 GHz and for temperatures as high as 1000°C.

scholarly journals On the development of a novel high VSWR programmable impedance tuner

2016 ◽  
Vol 8 (4-5) ◽  
pp. 723-730
Author(s):  
Arnaud Curutchet ◽  
Anthony Ghiotto ◽  
Manuel Potéreau ◽  
Magali De Matos ◽  
Sébastien Fregonese ◽  
...  
Keyword(s):  
Standing Wave ◽  
Frequency Band ◽  
High Voltage ◽  
Characteristic Impedance ◽  
Coaxial Line ◽  
Experimental Results ◽  
Microwave Frequencies ◽  
Microwave Components ◽  
Push Forward ◽  
Impedance Tuners

Impedance tuners are key instruments used for load- and source–pull measurements. They are crucial for any active microwave components, circuits, and systems characterization and optimization. This paper reports theoretical, simulated, and experimental results related to the development of a novel programmable impedance tuner offering high-voltage standing wave ratio (VSWR). After presenting the proposed tuner principle, a fabricated prototype operating at microwave frequencies and based on a 3.5 mm coaxial line is introduced with experimental results. Depending on the targeted frequency band, different pairs of slugs, with optimized length and characteristic impedance, can be used to obtain an optimal VSWR. This first prototype allowed us to demonstrate the interest of the proposed impedance synthesis principle and to identify ways forward to further improve its performances and push forward this promising technology.

Fdtd Simulations And Analysis Of Thin Sample Dielectric Properties Measurements Using Coaxial Probes

1996 ◽  
Vol 430 ◽  
Author(s):  
S. Bringhurst ◽  
M. F. Iskander ◽  
M. J White
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Frequency Band ◽  
Protective Layer ◽  
Alumina Tube ◽  
Nickel Plating ◽  
Thin Sample ◽  
Coaxial Probes ◽  
Fdtd Simulations ◽  
Complete Frequency

AbstractA metallized ceramic probe has been designed for high temperature broadband dielectric properties measurements. The probe was fabricated out of an alumina tube and rod as the outer and inner conductors respectively. The alumina was metallized with a 3 mil layer of moly-manganese and then covered with a 0.5 mil protective layer of nickel plating. The probe has been used to make complex dielectric properties measurements over the complete frequency band from 500 MHz to 3 GHz, and for temperatures as high as 1000 °C.

scholarly journals Ameliorated Mechanical and Dielectric Properties of Heat-Resistant Radome Cyanate Composites

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3117
Author(s):  
Hou-Yu Li ◽  
Chang-Ming Li ◽  
Jun-Guo Gao ◽  
Wei-Feng Sun
Keyword(s):  
High Temperature ◽  
Dielectric Properties ◽  
Heat Resistance ◽  
Dielectric Breakdown ◽  
Wave Transmission ◽  
Experimental Results ◽  
Electrical Insulation ◽  
Breakdown Field ◽  
Tensile Fracture ◽  
Heat Resistant

In order to improve the mechanical and dielectric properties of radome cyanate, a synergistic reinforcement method is employed to develop a resin-based ternary-composite with high heat-resistance and preferable radar-band transmission, which is expected to be applied to fabricate radomes capable of resisting high temperature and strong electric field. According to copolymerization characteristics and self-curing mechanism, epoxy resin (EP) and bismaleimide (BMI) are employed as reinforcements mixed into a cyanate ester (CE) matrix to prepare CE/BMI/EP composites of a heat-resistant radome material by high-temperature viscous-flow blending methods under the catalysis of aluminum acetylpyruvate. The crystallization temperature, transition heat, and reaction rate of cured polymers were tested to analyze heat-resistance characteristics and evaluate material synthesis processes. Scanning electron microscopy was used to characterize the micro-morphology of tensile fracture, which was combined with the tensile strength test and dynamic thermomechanical analysis to investigate the composite modifications on tenacity and rigidity. Weibull statistics were performed to analyze the experimental results of the dielectric breakdown field, and the dielectric-polarization and wave-transmission performances were investigated according to alternative current dielectric spectra. Compared with the pure CE and the CE composites individually reinforced by EP or BMI, the CE/BMI/EP composite acquires the most significant amelioration in both the mechanical and electrical insulation performances as indicated by the breaking elongation and dielectric breakdown strength being simultaneously improved by 40%, which are consistently manifested by the obviously increased transverse lines uniformly distributed on the fracture cross-section. Furthermore, the glass-transition temperature of CE/BMI/EP composite reaches the highest values of nearly 300 °C, with the relative dielectric constant and dielectric loss being mostly reduced to less than 3.2 and 0.01, respectively. The experimental results demonstrate that the CE/BMI/EP composite is a highly-qualified wave-transmission material with preferences in mechanical, thermostability, and electrical insulation performances, suggesting its prospective applications in low-frequency transmittance radomes.

Hydrodynamic Loads on Flexible Marine Structures due to Vortex Shedding

1982 ◽  
Vol 104 (4) ◽  
pp. 330-336 ◽  
Author(s):  
M. J. Every ◽  
R. King ◽  
O. M. Griffin
Keyword(s):  
Vortex Shedding ◽  
Reduction Method ◽  
Experimental Results ◽  
Experimental Measurements ◽  
Marine Structures ◽  
Flow Induced Vibration ◽  
Hydrodynamic Loads ◽  
Vortex Induced Vibrations ◽  
Air Blowing ◽  
Made In

This paper makes a comparison of experimental measurements and a recently developed methodology for the prediction of the increase in the steady drag of a cylinder undergoing vortex-induced vibrations. The experimental results were obtained during the development of a means to reduce the flow-induced vibration of a cable-suspended pile of the COGNAC platform installation and agree well with the predictions made in this paper. Next, a brief consideration is made of some of the authors’ experience of methods used to reduce vortex-induced vibrations, and hence stress levels. Finally, a reduction method which used an air-blowing manifold is described and results presented.

MULTIMET (N-155)

Alloy Digest ◽  
1961 ◽  
Vol 10 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
Age Hardening ◽  
Nickel Chromium ◽  
Cobalt Nickel ◽  
Temperature Performance ◽  
High Oxidation ◽  
Scaling Resistance ◽  
Made In

Abstract MULTIMET alloy is cobalt-nickel-chromium-iron austenitic alloy having high oxidation and scaling resistance along with good high-temperature properties. It tends to work harden but does not respond significantly to age-hardening. It is made in a wrought grade (0.08-0.16% carbon) and a casting grade (0.20% max. carbon). This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SS-28. Producer or source: Haynes Stellite Company. Originally published May 1955, revised December 1961.

Sign in / Sign up

Export Citation Format

Share Document