scholarly journals Research status and development trend of ceramifiable silicone rubber composites: a brief review

2021 ◽  
Author(s):  
Jianhua Li
Keyword(s):  
Mechanical Properties ◽  
Silicone Rubber ◽  
High Speed ◽  
High Performance ◽  
Degradation Mechanism ◽  
Research Work ◽  
Development Trend ◽  
High Tech ◽  
Reaction Products ◽  
Rubber Composites

Abstract Ceramifiable silicone rubber composites (CSR) are one of the most important industrially produced elastic technical materials. At present, there is a strong demand for CSR in the high-tech fields of high-speed rail, nuclear power, rocket and aerospace, which are still to be met. Many scholars have committed to the research work of improving the thermal stability, flame retardant, mechanical properties by changing the silicone rubber (SR) matrixes and filler, tremendous advances in CSR have been made for over the last decades where CSR intended for the high technology fields has evolved through different generations. In summary, the first-generation research is based on matrix reaction, the second-generation research is on reaction products, and the third-generation research is on fillers effects. In this review, the evolution of CSR and the synthesis routes, reaction mechanism, and degradation mechanism are introduced and analysed; fillers, various types of CSR based composites as well as the flame retardancy and mechanical properties are reviewed. Finally, the problems of developing high-performance CSRs are proposed and discussed. This review provides a theoretical basis and supporting data for the application of high-performance CSR, as well as provides details on the fire prevention mechanism of CSR.

scholarly journals Mechanical Properties and Reaction Characteristics of Al-ZrH2-PTFE Composites under Quasi-Static Compression

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 421 ◽  
Author(s):  
Jun Zhang ◽  
Xiang Fang ◽  
Yuchun Li ◽  
Zhongshen Yu ◽  
Junyi Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Reaction Mechanism ◽  
High Speed ◽  
Calorific Value ◽  
Reaction Rates ◽  
Zirconium Hydride ◽  
Reaction Products ◽  
Static Compression ◽  
Reaction Characteristics ◽  
Quasi Static Compression

To analyze the mechanical properties and reaction characteristics of Al-ZrH2-PTFE (aluminum-zirconium hydride-polytetrafluoroethylene) composites under quasi-static compression, five types of specimens with different ZrH2 contents (0%, 5%, 10%, 20% and 30%) were prepared by molding-vacuum sintering. The true stress-strain curves and reaction rates of the different specimens were measured using quasi-static compression. The specific reaction processes were recorded by a high-speed camera. The corresponding reaction products were characterized by the XRD phase analysis, the calorific value was tested by a Calorimeter, and the reaction mechanism was analyzed. According to the results, the strength of the composites increased first and then decreased with the increase in the content of ZrH2. It reached a maximum of 101.01 MPa at 5%. Violent reaction occurred, and special flames were observed during the reaction of the specimens with 5% ZrH2. With the increase in the content of ZrH2, the chemical reaction was hard to induce due to the reduction in strength and toughness of composites. The reaction mechanism of Al/ZrH2/PTFE reveals that high temperatures at crack tip induced the reaction of Al and PTFE. Subsequently, ZrH2 decomposed to release hydrogen and generate ZrC. Calorimetric experiment shows that the calorific value of Al/ZrH2/PTFE with 20% ZrH2 is higher than that of Al/PTFE. The findings verify the potential of ZrH2 as an energetic additive for the enhancement of strength and release of the energy of the composites.

scholarly journals Review on the Effect of the Phenomenon of Cavitation in Combustion Efficiency and the Role of Biofuels as a Solution against Cavitation

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7265
Author(s):  
Ludovic Lamoot ◽  
Brady Manescau ◽  
Khaled Chetehouna ◽  
Nicolas Gascoin
Keyword(s):  
High Speed ◽  
High Performance ◽  
Research Work ◽  
Combustion Process ◽  
Energy Transition ◽  
Combustion Efficiency ◽  
Review Article ◽  
Cavitation Phenomenon ◽  
Heat Engines ◽  
High Speeds

Concerning the problem of wanting the performance of heat engines used in the automotive, aeronautics, and aerospace industries, researchers and engineers are working on various possibilities for improving combustion efficiency, including the reduction of gases such as CO, NOx, and SOx. Such improvements would also help reduce greenhouse gases. For this, research and development has focused on one factor that has a significant impact on the performance of these engines: the phenomenon of cavitation. In fact, most high-performance heat engines are fitted with a high-speed fuel supply system. These high speeds lead to the formation of the phenomenon of cavitation generating instabilities in the flow and subsequently causing disturbances in the combustion process and in the efficiency of the engine. In this review article, it is a question of making a state-of-the-art review on the various studies which have dealt with the characterization of the phenomenon of cavitation and addressing the possible means that can be put in place to reduce its effects. The bibliographic study was carried out based on five editors who are very involved in this theme. From the census carried out, it has been shown that there are many works which deal with the means of optimization that must be implemented in order to fight against the phenomenon of cavitation. Among these solutions, there is the optimization of the geometry of the injector in which the fuel flows and there is the type of fuel used. Indeed, it is shown that the use of a biofuel, which, by its higher viscosity, decreases the effects of cavitation. Most of these jobs are performed under cold fluidic conditions; however, there is little or no work that directly addresses the effect of cavitation on the combustion process. Consequently, this review article highlights the importance of carrying out research work, with the objective of characterizing the effect of cavitation on the combustion process and the need to use a biofuel as an inhibitor solution on the cavitation phenomenon and as a means of energy transition.

scholarly journals Resource Based Capability and Competitive Strategy of High-Tech Ventures in Kerala

2019 ◽  
Vol 8 (4) ◽  
pp. 138-143
Keyword(s):  
Cluster Analysis ◽  
Competitive Strategy ◽  
High Performance ◽  
New Ventures ◽  
Research Work ◽  
Innovation Strategy ◽  
Survey Method ◽  
High Tech ◽  
Marketing Capability ◽  
The Impact

The paper examines the impact of resource- based capability and competitive strategy on the performance of hightech new ventures in Kerala. The resource-based capability was analyzed using the variables managerial capability, technical capability, marketing capability and input sourcing capability of the firm. Competitive strategy was measured by looking into cost strategy, quality strategy, innovation strategy, and customization strategy adopted by the firm. A descriptive research was undertaken to analyze the performance of the ventures. A survey method was administered to collect data from 83 high- tech startups in Kerala. Independent sample t-test, Multiple regression and Cluster analysis were used to arrive at a conclusion. The findings indicate that both resource- based capability and competitive strategy influences the performance of a venture. It was found that the entrepreneurs of profitable ventures exhibit better managerial capability. The results of the cluster analysis show that the entrepreneurs with high performance indicators are customer centric. The innovation strategy and marketing capability adopted by the firm has an impact on the venture performance. The findings suggest that sales, profitability and financial position can be predicted to an extend by the resourcebased capability and competitive strategy adopted by the venture. The research work can be used by emerging entrepreneurs, policymakers and incubation managers to develop a framework to improve the performance of startups.

scholarly journals Compressive and Flexural Strength Property Enhancement for Fibre Reinforced Standard Concrete (FRSC), High Strength Concrete (FRHSC) and High Performance Concrete (FRHPC) using Foundry Sand (FS) and Crushed Concrete Waste (CCW)

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Pruthviraj S R ◽  
Ravi Kumar C M ◽  
Yajnodbhavi H M ◽  
Maruthi T ◽  
Raghavendra S
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Research Work ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Specific Test ◽  
Foundry Sand ◽  
Crushed Concrete

Now days, many research works are carried for all grades of concrete to make the concrete most economical and durable there by adding the supplementary cementitious materials and alternative replacement aggregates. In this research work deals with the experimental investigation of mechanical properties of the M30, M50 and M80 grade concrete by replacing the fine and coarse aggregate by foundry sand and crushed concrete waste respectively. Mix design procedures were followed as per IRC44:2017 guidelines and recommendation. Proper dosage of super plasticizer (SP) was maintained in the concrete to make it better performed. In this present investigation, a Poly Propylene fibre (PPF) of 0.3% by weight of the cement is used. Mechanical properties such as Compressive strength and Flexural Strength were determined by preparing the respective mould sizes for specific test and are cured for 7, 14 and 28 days and result obtained for respective days were tabulated and discussed.  

Influence of Different Mechanical Properties to the Concrete Penetration Resistance

2014 ◽  
Vol 982 ◽  
pp. 119-124 ◽  
Author(s):  
Tomáš Vavřiník ◽  
Jan Zatloukal
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
High Speed ◽  
High Performance ◽  
High Performance Concrete ◽  
Penetration Resistance ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Steel Fiber Reinforced Concrete

This paper describes influence of different mechanical properties to the concrete penetration resistance. The resistance is evaluated on the basis of the presented experimental program. In the experiment, non-deformable ogive-nose projectiles with diameter of 7.92 mm and mass of 8 g with impact velocity of about 700 m/s were hitting center of the specimens. Determination of the concrete penetration resistance was than based on projectile residual velocity obtained from high-speed camera record. The specimens were made from high strength concrete, steel fiber-reinforced concrete, ultra-high performance concrete and ultra-high performance fiber-reinforced concrete with different fiber content. The concrete penetration resistance was evaluated on total 32 specimens. Influence of mechanical properties, addition of coarse aggregate and steel fibers were discussed. Mechanical properties of the tested materials were investigated on total 125 specimens. Data from the measurements were used for creation of new RHT concrete models in Autodyn. In order to confirm experiment's setup and results, numerical analysis was performed in Autodyn. Results of the numerical simulations were compared to the experimental program.

Effect of hybrid hollow microspheres on thermal insulation performance and mechanical properties of silicone rubber composites

2017 ◽  
Vol 135 (11) ◽  
pp. 46025 ◽  
Author(s):  
Xiong-Wei Zhao ◽  
Chong-Guang Zang ◽  
Ya-Lun Sun ◽  
Yu-Long Zhang ◽  
Yu-Quan Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Insulation ◽  
Silicone Rubber ◽  
Hollow Microspheres ◽  
Rubber Composites ◽  
Insulation Performance
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