Characterization of the Matrix Glass Transition in Carbon-Epoxy Laminates Using the CSD Test Geometry

Glass in Na2O-CaO-SiO2 was synthesized by conventional molten cooling method and then converted to glass-ceramics. Transparent glass-ceramics obtained by controlled crystallization process. DSC, SEM and XRD were used to determine the character temperature, microstructure and crystal type of the glass-ceramics, respectively. The results show the transition temperature of the matrix glass is 620°C and crystallization peak temperature is 730°C. Only Na2Ca2Si3O9 crystal phase was found in the glass-ceramics when the matrix glass was treated at 750°C for 1h. The crystal with size of 0.5um arranged regularly and formed a honeycomb-like structure in the glass-ceramics. UV-visible spectrum test indicate the transmittance of the glass-ceramic is as high as 75% in the visible region.

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TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105758 ◽

1988 ◽

Vol 46 ◽

pp. 738-739

Author(s):

G. Das ◽

R. E. Omlor

Keyword(s):

Titanium Alloys ◽

Reaction Zone ◽

Carbon Layer ◽

Fiber Reinforced ◽

Reaction Products ◽

Sic Fibers ◽

Sic Fiber ◽

The Matrix ◽

Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

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Characterization of the Structure, Mechanical Properties and Erosive Resistance of the Laser Cladded Inconel 625-Based Coatings Reinforced by TiC Particles

Materials ◽

10.3390/ma14092225 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2225

Author(s):

Aleksandra Kotarska ◽

Tomasz Poloczek ◽

Damian Janicki

Keyword(s):

Laser Cladding ◽

Inconel 625 ◽

Matrix Composites ◽

Erosion Rates ◽

Laser Cladding Process ◽

Composition Variation ◽

The Matrix ◽

Reinforcing Material ◽

Inconel 625 Superalloy

The article presents research in the field of laser cladding of metal-matrix composite (MMC) coatings. Nickel-based superalloys show attractive properties including high tensile strength, fatigue resistance, high-temperature corrosion resistance and toughness, which makes them widely used in the industry. Due to the insufficient wear resistance of nickel-based superalloys, many scientists are investigating the possibility of producing nickel-based superalloys matrix composites. For this study, the powder mixtures of Inconel 625 superalloy with 10, 20 and 40 vol.% of TiC particles were used to produce MMC coatings by laser cladding. The titanium carbides were chosen as reinforcing material due to high thermal stability and hardness. The multi-run coatings were tested using penetrant testing, macroscopic and microscopic observations, microhardness measurements and solid particle erosive test according to ASTM G76-04 standard. The TiC particles partially dissolved in the structure during the laser cladding process, which resulted in titanium and carbon enrichment of the matrix and the occurrence of precipitates formation in the structure. The process parameters and coatings chemical composition variation had an influence on coatings average hardness and erosion rates.

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Mechanical characterization of LM25 alloy matrix composite reinforced with boron carbide

Journal of Composite Materials ◽

10.1177/00219983211005513 ◽

2021 ◽

pp. 002199832110055

Author(s):

Zeeshan Ahmad ◽

Sabah Khan

Keyword(s):

Tensile Strength ◽

Boron Carbide ◽

Mechanical Characterization ◽

Stir Casting ◽

Surface Mapping ◽

Alloy Matrix ◽

Casting Technique ◽

The Matrix ◽

Carbide Particles

Alumnium alloy LM 25 based composites reinforced with boron carbide at different weight fractions of 4%, 8%, and 12% were fabricated by stir casting technique. The microstructures and morphology of the fabricated composites were studied by scanning electron microscopy and energy dispersive spectroscopy. Elemental mapping of all fabricated composites were done to demonstrate the elements present in the matrix and fabricated composites. The results of microstructural analyses reveal homogenous dispersion of reinforcement particles in the matrix with some little amount of clustering found in composites reinforced with 12% wt. of boron carbide. The mechanical characterization is done for both alloy LM 25 and all fabricated composites based on hardness and tensile strength. The hardness increased from 13.6% to 21.31% and tensile strength 6.4% to 22.8% as reinforcement percentage of boron carbide particles increased from 0% to 12% wt. A fractured surface mapping was also done for all composites.

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Reliability Assessment of a Multi-State HVDC System by Combining Markov and Matrix-Based Methods

Energies ◽

10.3390/en14113097 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3097

Author(s):

Roberto Benato ◽

Antonio Chiarelli ◽

Sebastian Dambone Sessa

Keyword(s):

Current System ◽

Estimation Method ◽

Reliability Estimation ◽

Voltage Source ◽

Voltage Source Converter ◽

Hvdc System ◽

Critical Elements ◽

The Matrix ◽

The Impact

The purpose of this paper is to highlight that, in order to assess the availability of different HVDC cable transmission systems, a more detailed characterization of the cable management significantly affects the availability estimation since the cable represents one of the most critical elements of such systems. The analyzed case study consists of a multi-terminal direct current system based on both line commutated converter and voltage source converter technologies in different configurations, whose availability is computed for different transmitted power capacities. For these analyses, the matrix-based reliability estimation method is exploited together with the Monte Carlo approach and the Markov state space one. This paper shows how reliability analysis requires a deep knowledge of the real installation conditions. The impact of these conditions on the reliability evaluation and the involved benefits are also presented.

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Design of an n-type low glass transition temperature radical polymer

Polymer Chemistry ◽

10.1039/d0py01645d ◽

2021 ◽

Author(s):

Teng Chi ◽

Siddhartha Akkiraju ◽

Zihao Liang ◽

Ying Tan ◽

Ho Joong Kim ◽

...

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Synthesis And Characterization ◽

Design Synthesis

We document the design, synthesis, and characterization of the first low glass transition temperature, n-type (i.e., preferentially-reduced) radical polymer.

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Characterization of Mmp37p, aSaccharomyces cerevisiaeMitochondrial Matrix Protein with a Role in Mitochondrial Protein Import

Molecular Biology of the Cell ◽

10.1091/mbc.e06-04-0366 ◽

2006 ◽

Vol 17 (9) ◽

pp. 4051-4062 ◽

Cited By ~ 47

Author(s):

Michelle R. Gallas ◽

Mary K. Dienhart ◽

Rosemary A. Stuart ◽

Roy M. Long

Keyword(s):

Matrix Protein ◽

Protein Import ◽

Mitochondrial Protein ◽

Temperature Sensitive ◽

Inner Membrane ◽

Mitochondrial Inner Membrane ◽

Close Proximity ◽

The Matrix ◽

Targeting Signal

Many mitochondrial proteins are encoded by nuclear genes and after translation in the cytoplasm are imported via translocases in the outer and inner membranes, the TOM and TIM complexes, respectively. Here, we report the characterization of the mitochondrial protein, Mmp37p (YGR046w) and demonstrate its involvement in the process of protein import into mitochondria. Haploid cells deleted of MMP37 are viable but display a temperature-sensitive growth phenotype and are inviable in the absence of mitochondrial DNA. Mmp37p is located in the mitochondrial matrix where it is peripherally associated with the inner membrane. We show that Mmp37p has a role in the translocation of proteins across the mitochondrial inner membrane via the TIM23-PAM complex and further demonstrate that substrates containing a tightly folded domain in close proximity to their mitochondrial targeting sequences display a particular dependency on Mmp37p for mitochondrial import. Prior unfolding of the preprotein, or extension of the region between the targeting signal and the tightly folded domain, relieves their dependency for Mmp37p. Furthermore, evidence is presented to show that Mmp37 may affect the assembly state of the TIM23 complex. On the basis of these findings, we hypothesize that the presence of Mmp37p enhances the early stages of the TIM23 matrix import pathway to ensure engagement of incoming preproteins with the mtHsp70p/PAM complex, a step that is necessary to drive the unfolding and complete translocation of the preprotein into the matrix.

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