The Effect of Temperature Elevation on Microwave-Transmitting Property of Organosilicone-Matrix Radome

2016 ◽  
Vol 848 ◽  
pp. 174-178
Author(s):  
Qian Wang
Keyword(s):  
High Temperature ◽  
Theoretical Model ◽  
Operating Temperature ◽  
Dielectric Spectrum ◽  
Effect Of Temperature ◽  
Matrix Composites ◽  
Temperature Elevation ◽  
Gradient Distribution ◽  
Spectrum Measurement ◽  
Different Temperatures

In this paper, both the permittivity and the microwave transmittance properties of organosilicon-matrix composites under different temperatures have been studied. In order to investigate the reason for the changing of dielectric property, both TGA and high-temperature dielectric spectrum measurement have been carried out. A theoretical model of radome, with a temperature gradient distribution, has been built to analyze the dependence of microwave transmittance property on temperature. Based on the experimental results, we can optimize the effective operating temperature of this kind of organosilicone-matrix composites.

Mechanical Response of T300/BMP350 Composites under Tensile Loading at Room and Elevated Temperatures

2014 ◽  
Vol 1035 ◽  
pp. 138-143
Author(s):  
Ping Zhou ◽  
Pu Rong Jia ◽  
Wen Ge Pan
Keyword(s):  
High Temperature ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Mechanical Response ◽  
Effect Of Temperature ◽  
Matrix Composites ◽  
Stress Strain ◽  
Damage And Failure ◽  
Different Temperatures ◽  
Static Tensile

In this paper, the effect of elevated temperature on the behavior of carbon fiber-reinforced T300/BMP350 unidirectional laminates was studied by loading static tensile on 0°, 90°and ±45° lay-up. The stress-strain relationships of the laminates under different temperatures were obtained. The effect of temperature on the mechanical properties of materials was systematically studied. The damage and failure mechanisms of the material were studied by analyzing the material stress-strain curves and the failure modes. Results show that the T300/BMP350 polyimide matrix composites have a strong resistance to high temperature. For 0° and 90° lay-up, the retentions of tensile strength and modulus are more than 80% and 50%, respectively. High temperature has little effect on the material failure modes. Finally, based on the test results, an empirical formula which relates strength and temperature of the material was fitted.

Experimental Evaluation of Abradable Seal Performance at High Temperature

2008 ◽  
Author(s):  
A. Dadouche ◽  
M. J. Conlon ◽  
W. Dmochowski ◽  
B. Liko ◽  
J.-P. Bedard
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Gas Turbines ◽  
Operating Temperature ◽  
Microstructural Analysis ◽  
Operating Conditions ◽  
Effect Of Temperature ◽  
Gas Leakage ◽  
Series Of Experiments ◽  
Aero Engines

Abradable seals have been used in aero-engines and land-based gas turbines for more than three decades. They are applied to various sections of the engine in order to reduce gas leakage by optimizing the gap between rotating and stationary parts. This optimization represents a significant increase in efficiency and decrease in fuel consumption. Performance evaluation of any abradable seal includes measurement of its mechanical properties, abradability tests and (ultimately) tests in engines. The aim of this paper is to study the effect of temperature on the rub performance of abradable seals. A series of experiments has been carried out in order to evaluate a commercially available seal material at different operating conditions. The effect of operating temperature on contact force, abrasion scar appearance and blade wear is examined and analyzed. A microstructural analysis of the rub scar has also been performed.

Modeling of Temperature-Dependent Hardness for Pure FCC and HCP Metals

2020 ◽  
Vol 12 (02) ◽  
pp. 2050022
Author(s):  
Niandong Xu ◽  
Weiguo Li ◽  
Jianzuo Ma ◽  
Yong Deng ◽  
Haibo Kou ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Melting Point ◽  
Present Model ◽  
Experimental Results ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Different Temperatures ◽  
Pure Metals ◽  
Experimental Values ◽  
Hardness Values

In this study, a theoretical model is developed to characterize the quantitative effect of temperature on the hardness of pure FCC and HCP metals. The model is verified by comparison with the available experimental results of Cu, Al, Zn, Mg, Be, Zr, Ni, Ir, Rh, and Ti at different temperatures. Compared with the widely quoted Westbrook model and Ito–Shishokin model which need piecewise fitting to describe experimental values, the present model merely needs two hardness values at different temperatures to predict the experimental results, reducing reliance on conducting lots of experiments. This work provides a convenient method to predict temperature-dependent hardness of pure metals, and it is worth noting that it can be applied to a wide temperature range from absolute zero to melting point.

scholarly journals Design of High Temperature Ti–Al–Cr–V Alloys for Maximum Thermodynamic Stability Using Self-Organizing Maps

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 537 ◽  
Author(s):  
Rajesh Jha ◽  
George S. Dulikravich
Keyword(s):  
High Temperature ◽  
Metallic Alloys ◽  
Effect Of Temperature ◽  
Large Dataset ◽  
Self Organizing Maps ◽  
Young’S Moduli ◽  
Starting Point ◽  
Different Temperatures ◽  
Effect Of The Composition ◽  
Self Organizing

Data generated for the Ti–Al–Cr–V system of metallic alloys from our previous publication, where the composition of 102 alloys were computationally Pareto optimized with the objective of simultaneously maximizing the Young’s modulus and minimizing density for a range of temperatures, was the starting point of the current research, where compositions at different temperatures of these alloys were analyzed for phase stability in order to generate new data for compositions and volume fractions of stable phases at various temperatures. This resulted in a large dataset where a lot of data were still missing as all the phases are not stable at a given temperature for all the compositions. The concept of Self-Organizing Maps (SOM) was then applied to determine correlations between alloy compositions, stabilities of desired phases at various temperatures, associated Young’s moduli and densities, and the effect of the composition of phases on these properties. This work should help alloy designers to determine the required chemical composition of a new alloy with reference to the temperature of application of that alloy and see the effect of temperature and composition on stable phases and associated properties of alloys.

scholarly journals Effect of deformation on densification and corrosion behavior of Al-ZrB2 composite

10.30544/264 ◽  
2017 ◽  
Vol 23 (1) ◽  
pp. 47-63 ◽  
Author(s):  
Sai Mahesh Yadav Kaku ◽  
Asit Kumar Khanra ◽  
M J Davidson
Keyword(s):  
Metal Matrix ◽  
Effect Of Temperature ◽  
Controlled Atmosphere ◽  
Matrix Composites ◽  
Dynamic Polarization ◽  
Mechanical Working ◽  
Argon Gas ◽  
Aspect Ratios ◽  
Different Temperatures ◽  
Polarization Studies

In the present investigation, aluminium based metal matrix composites (MMCs) were produced through powder metallurgical route. Different composites were processed by adding different amount of ZrB2 (0, 2, 4 and 6 wt. %) at three aspect ratios of 0.35, 0.5, and 0.65, respectively. The powder mixture was compacted and pressureless sintered at 550 °C for 1 h in controlled atmosphere (argon gas). The relative density of the sintered preforms was found to be 90%, approximately. Sintered preforms are used as workpiece materials for deformation study at different temperatures in order to find the effect of temperature on the densification behaviour. Potentio-dynamic polarization studies were performed on the deformed preforms to find the effect of mechanical working. The corrosion rate was found to decrease with increase in deformation.

Interface reactions in a high-temperature metal-matrix composite

1989 ◽  
Vol 47 ◽  
pp. 560-561
Author(s):  
L. F. Allard ◽  
D. W. Coffey ◽  
E. K. Ohriner ◽  
V. K. Sikka
Keyword(s):  
High Temperature ◽  
Nickel Aluminide ◽  
Metal Matrix ◽  
Operating Temperature ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Ceramic Fibers ◽  
Interface Reactions ◽  
Stress Environments ◽  
Fiber Matrix Interface

Metal-matrix composites are currently of interest for application in high-temperature, elevated-stress environments. Of a number of such materials currently being investigated in our laboratory, nickel aluminides reinforced with ceramic whiskers or fibers have shown promise in that the maximum operating temperature of the alloy has been extended from 800°C to 1100°C. The microstructure of the fiber/matrix interface in a nickel aluminide strengthened with ceramic fibers is detailed in this paper.The composite material was fabricated by mixing gas-atomized −100 mesh IC-50 powder (11.7 Al, 1.76 Hf, 0.025 B wt %, bal. Ni) with Nextel 440 fiber (3M Co., nominally 70 A12O3, 28 SiO2 and 2 B2O3 wt %) to give a composite with about 20 vol % fiber. The material was placed in a heavy-walled stainless-steel can which was evacuated while being heated to 600°C to remove fiber sizing. The can was subsequently sealed and preheated at 1100° C for 2 h, then hot consolidated at high pressure for 30 s to produce a fully dense material.

High-temperature tensile properties of in situ-synthesized titanium matrix composites with strong dependence on strain rates

2008 ◽  
Vol 23 (11) ◽  
pp. 3066-3074 ◽  
Author(s):  
Lv Xiao ◽  
Weijie Lu ◽  
Jining Qin ◽  
Di Zhang ◽  
Minmin Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Strain Rate ◽  
Tensile Properties ◽  
Strong Dependence ◽  
Strain Rates ◽  
Matrix Composites ◽  
Titanium Matrix ◽  
Titanium Matrix Composites ◽  
The Matrix ◽  
Different Temperatures

High-temperature titanium matrix composites reinforced with hybrid reinforcements are synthesized by common casting and hot working technologies. Tensile properties are tested at different temperatures and strain rates. Ultimate strengths of the composites are significantly enhanced under all conditions and decrease when the strain rate is lower. Equicohesive temperature of the matrix is around 873 K at the strain rate 10−3s−1 and well below 873 K at 10−5s−1. At higher temperature or lower strain rate, interfacial debonding is more drastic and reduces the strengths of composites. The materials are embrittled under creep-rupture conditions. Strict reinforcement morphology is required for more complex service conditions at high temperatures in metal matrix composites.

scholarly journals Investigation of the impact of a broad range of temperatures on the physiological and transcriptional profiles of Zymomonas mobilis ZM4 for high-temperature-tolerant recombinant strain development

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Runxia Li ◽  
Wei Shen ◽  
Yongfu Yang ◽  
Jun Du ◽  
Mian Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Ethanol Production ◽  
Heat Tolerance ◽  
Zymomonas Mobilis ◽  
Glucose Utilization ◽  
Effect Of Temperature ◽  
Rna Seq ◽  
Transcriptional Profiles ◽  
Different Temperatures ◽  
The Impact

AbstractThe model ethanologenic bacterium Zymomonas mobilis has many advantages for diverse biochemical production. Although the impact of temperature especially high temperature on the growth and ethanol production of Z. mobilis has been reported, the transcriptional profiles of Z. mobilis grown at different temperatures have not been systematically investigated. In this study, Z. mobilis wild-type strain ZM4 was used to study the effect of a broad range of temperatures of 24, 30, 36, 40, and 45 °C on cell growth and morphology, glucose utilization and ethanol production, as well as the corresponding global gene expression profiles using RNA-Seq-based transcriptomics. In addition, a recombinant Z. mobilis strain expressing reporter gene EGFP (ZM4_EGFP) was constructed to study the effect of temperature on heterologous protein expression at different temperatures. Our result demonstrated that the effect of temperature on the growth and morphology of ZM4 and ZM4_EGFP were similar. The biomass of these two strains decreased along with the temperature increase, and an optimal temperature range is needed for efficient glucose utilization and ethanol production. Temperatures lower or higher than normal temperature investigated in this work was not favorable for the glucose utilization and ethanol production as well as the expression of exogenous protein EGFP based on the results of flow cytometry and Western blot. Temperature also affected the transcriptional profiles of Z. mobilis especially under high temperature. Compared with ZM4 cultured at 30 °C, 478 genes were up-regulated and 481 genes were down-regulated at 45 °C. The number of differentially expressed genes of ZM4 cultured at other temperatures (24, 36 or 40 °C) was relatively small though compared with those at 30 °C. Since temperature usually increases during the fermentation process, and heat tolerance is one of the important robustness traits of industrial strains, candidate genes related to heat resistance based on our RNA-Seq result and literature report were then selected for genetics study using the strategies of plasmid overexpression of candidate gene or replacement of the native promoter of candidate gene by an inducible Ptet promoter. The genetics studies indicated that ZMO0236, ZMO1335, ZMO0994, operon groESL, and cspL, which encodes Mrp family chromosome partitioning ATPase, flavoprotein WrbA, an uncharacterized protein, chaperonin Cpn10 and GroEL, and an exogenous cold shock protein, respectively, were associated with heat tolerance, and recombinant strains over-expressing these genes can improve their heat tolerance. Our work thus not only explored the effects of temperature on the expression of exogenous gene EGFP and endogenous genes, but also selected and confirmed several genes associated with heat tolerance in Z. mobilis, which provided a guidance on identifying candidate genes associated with phenotypic improvement through systems biology strategy and genetics studies for other microorganisms.

scholarly journals Influence of Temperature on Mechanical Properties of AMCs

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 783 ◽  
Author(s):  
E.S. Caballero ◽  
Fátima Ternero ◽  
Petr Urban ◽  
Francisco G. Cuevas ◽  
Jesús Cintas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Gas Flow ◽  
Room Temperature ◽  
Tensile Tests ◽  
Effect Of Temperature ◽  
Matrix Composites ◽  
Vacuum Sintering ◽  
Ammonia Gas ◽  
Aluminium Powder

This research focused on studying the effect of temperature on the mechanical properties of aluminium matrix composites (AMCs) obtained by a powder metallurgy route. Aluminium powder was milled at room temperature for 5 h and using different atmospheres in order to achieve different amounts of reinforcement. The atmospheres employed were vacuum, confined ammonia, and vacuum combined with a short-time (5 and 10 min) of ammonia gas flow. After mechanical alloying, powders were consolidated by cold uniaxial pressing (850 MPa) and vacuum sintering (650 °C, 1 h). Hardness and tensile tests, on consolidated samples, were carried out at room temperature. Subsequently, the effect of temperature on both properties were evaluated. On one hand, the UTS and hardness were measured, again at room temperature, but after having subjected the sintered samples to a prolonged annealing (400 °C, 100 h). On the other hand, the tensile and hardness behaviour were also studied, while the samples are at high temperature, in particular 250 °C for UTS, and in the range between 100 and 400 °C for hardness. Results show that the use of ammonia gas allows achieving mechanical properties, at room and high temperature, higher than those of the commercial alloys EN AW 2024 T4, and EN AW 7075 T6.

The Effects of Temperature on Rheology Properties and Filtrate after Using Lemongrass as Lost Circulation Materials for Oil Based Drilling Mud

2014 ◽  
Vol 911 ◽  
pp. 243-247 ◽  
Author(s):  
N.A. Ghazali ◽  
T.A.T. Mohd ◽  
N. Alias ◽  
M.Z. Shahruddin ◽  
A. Sauki ◽  
...  
Keyword(s):  
High Temperature ◽  
Filter Press ◽  
Effect Of Temperature ◽  
Drilling Mud ◽  
Lost Circulation ◽  
Water Based ◽  
Different Temperatures ◽  
Effects Of Temperature ◽  
Mud Loss ◽  
Lost Circulation Materials

Lost circulation materials (LCM) are used to combat mud loss to the reservoir formation which can cause problems during drilling operation. Difficulties in handling and costly are those challenges faced by drilling operator. Mostly LCM can work better in water based mud compared to oil based mud due to characteristic of LCM itself. Nowadays, most of operator interested in the ultra-deep water due to the limitation of reservesand deals with high temperature and high pressure conditions.Oil based mud (OBM) is more preferable in high temperature conditions compared to water based mud hence a laboratory study was carried out to investigate the effect of temperature on the performance of lemongrass with different sizes in oil based mud. The oil based mud was formulated and tested with three different temperatures which are 250oF, 275oF and 350oF. The lemongrass LCM was prepared with three different sizes which are 150 microns, 250 microns and 500 microns. The sizes distribution of LCM is one of the main contributors to the success of LCM in the formation. The oil based mud samples were tested using Fann Viscometer to determine rheology properties and HPHT Filter Press to investigate the amount of filtrate. It was found that different temperatures and sizes have great effects on the lemongrass LCM in the oil based mud. The optimum temperature for lemongrass LCM is 275oF and with the sizes of 250 microns.

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