Abstract:In this study, polyimide (PI)/Ag nanowire (AgNW) nanocomposite aerogels with extremely high mechanical performance have been fabricated utilizing amine-modified AgNWs as mechanical nanoreinforcement particulates and crosslinking agents. Initially, AgNWs were fabricated and surface modified by p-aminothiophenol (PATP), then the aminated AgNWs were dispersed into polyamide acid solution and aerogels were prepared by supercritical CO 2 drying. Raman and X-ray photoelectron spectroscopy (XPS) spectrometry were carried out on A-AgNWs (aminated Ag nanowires) to prove the successful modification. This functional nanoparticle greatly enhanced the strength and toughness of aerogels without evident increase in densities. Comparing to pure PI aerogels, samples with 2.0 wt % of A-AgNWs had a 148% increase in compression strength and 223% increase in Young's modulus, which equates to 2.41 and 27.66 MPa, respectively. Simultaneously, the tensile test indicated that aerogels with 2.0 wt % of A-AgNWs had a breaking energy of 40.18 J/m 3 , which is 112% higher than pure PI aerogels. The results presented herein demonstrate that aminated AgNWs are an innovative cross-linker for PI aerogels and can improve their strength and toughness. These aerogels have excellent potential as high-duty, lightweight porous materials in many areas of application.
After a loss of coolant accident (LOCA) in a pressurized water reactor (PWR), the chemical environment inside containment is complex; there is a potential trend for some materials to be corroded by high-temperature alkaline water.The subsequent corrosion products may be recirculated through the sump strainers using the emergency core cooling system (ECCS), and ultimately transported into the reactor core. This phenomenon would aggravate the blockage and head loss across the fuel assembly, thereby prohibiting decay heat transfer. To analyze the potential impact of "chemical effects" on flow resistance in the fuel assembly, the specific test loop was established and a series of analysis tests were performed. Four types of chemical precipitates were used in the tests: AlOOH, NaAlSi 3 O 8 , Ca 3 (PO 4 ) 2 , and Zn 3 (PO 4 ) 2 . This study concluded that the AlOOH precipitates could effectively increase pressure drop across the fibrous bed. The final head loss could also be affected by the physical and chemical characteristics of precipitates, such as the particle size, settling rate, and chemistry. K E Y W O R D Sblockage, chemical effects, LOCA, metal corrosion, pressure drop
Abstract:In order to study the applicability of the Fiber Reinforced Plastic (FRP) composite materials for light structure, a tensile compression test of a large number of FRP samples was carried out. Through statistically analysis of test data, we get the FRP's basic mechanical parameters like tensile strength, elongation, elastic modulus and we get the stress-strain curves. Compared with steel material properties, the tensile strength of the FRP is close to steel, but the elastic modulus is lower than steel's elastic modulus. PrefaceFiber Reinforced Plastic is also named Glass Fiber Reinforced Plastic, which is made of glass fiber or its products. [1] Due to the use of different resins, there are like polyester glass fiber, epoxy glass fiber, glass fiber reinforced phenolic. FRP is light and hard, not conductive, stable performance, high mechanical strength, corrosion resistance, and it can be used instead of steel to manufacture parts and automobiles, ships, and so on. [2] In recent years, FRP is obtained successful application of a high performance structural material in civil engineering structures, and has become an important supplement to the concrete, steel and other traditional materials.[3] But application of FRP material as a structural component is a frontier subject in the field of architecture, if FRP is used in light constructions, research and development of a new building materials and new building structure forms will greatly increase the scope of application of China and even the world in the field of building structures. [4] In order to study the applicability of FRP in light weight structural components, we need to know the basic mechanical properties of FRP, including the corresponding strength, elastic modulus and stress-strain curves. [5] Therefore, firstly, we need to solve the problems that the mechanical properties of FRP tests. Because of the development of FRP materials, the application scope is becoming wider, FRP's working environment is not limited in normal temperature, also at high temperature. Due to the use of different temperature, its mechanical properties are also different, compared with normal temperature, its performance will greatly different. Therefore, we have high temperature mechanical properties tests. Finally, compared with the experimental data and steel material properties, we will discuss the feasibility of FRP used in structure components.
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