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Theoretical Simulations on Physicochemical Performance of Novel High-energy BHDBT-based Propellants

Wang Ke, Huang Hai-tao, Xu Hui-xiang, Li Huan, Li Jun-qiang, Fan Xue-zhong, Pang Wei-qiang

Central European Journal of Energetic Materials

2021

Vol. 18, no. 1

5--24

Based on Energy Calculation Star program and molecular dynamic method, three designed 2,3-bis(hydroxymethyl)-2,3-dinitro-1,4-butanediol tetranitrate-based (BHDBT) propellants are firstly reported and their physicochemical performance are investigated. Results suggest that compared with HMX-based and CL-20-based propellants, the specific impulses of all BHDBT-based propellants surpass or approximate 280 s, which indicates the latter have the potential to be high-energy propellants. The diffusion coefficient of plasticizers in BHDBT-based propellant decrease as the temperature reduces, and reduce in the order: Bu-NENA > TMETN > BTTN. The densities of all BHDBT-based propellants surpass or approximate 1.7 g/cm3. The comparison of elastic constants, Poisson’s ratios and K/G values indicates that the mechanical properties of three BHDBT-based propellants increase in the order (by plasticizer): Bu-NENA < TMETN < BTTN. The bond length analysis of C–NO2 and O–NO2 bond in BHDBT suggests that the former is the trigger bond in the BHDBT-based propellants, and the safety of BHDBT-based propellants and BHDBT crystal decreases in the order: GAP/BTTN/Al/BHDBT > GAP/Bu-NENA/Al/BHDBT ≈ GAP/TMETN/Al/BHDBT > BHDBT. In conclusion, GAP/BTTN/Al/BHDBT propellant has the potential to be a novel high-energy propellant.

The Impact of Air Quality on Population Migration

Wang Ke, Wang Yiwei, Chang Chun Ping

Problemy Ekorozwoju

2020

Vol. 15, nr 2

23--31

Based on annual panel data of OECD countries from 1995 to 2014, this paper analyzes the impact of air quality (including per capita CO2, PM2.5, and SO emissions) on the immigrant population through a panel fixed-effect model, while employing control factors such as GDP, unemployment rate, and education level. Overall, we provide evidence that air quality is a key determinant of immigration in the selected countries, and in particular the host country’s emissions have a negative impact on immigrants. Greater emissions imply fewer immigrants, while fewer emissions denote more immigrants. Our findings provide countries with a way to more accurately estimate migrant inflow and offer an idea for OECD members on how to attract immigrants via an improvement in environmental quality.

Na podstawie rocznych danych panelowych krajów OECD za lata 1995-2014 w niniejszym artykule dokonano analizy wpływu jakości powietrza (w tym CO2 per capita, emisje PM2,5 i emisje SO) na populację imigrantów za pomocą panelu, biorąc pod uwagę czynniki, takie jak PKB, stopa bezrobocia i poziom wykształcenia. Dostarczamy dowodów, że jakość powietrza jest kluczowym czynnikiem determinującym migrację w wybranych krajach, a emisje z kraju przyjmującego mają negatywny wpływ na imigrantów. Większe emisje oznaczają mniej imigrantów, a mniej emisji oznacza więcej imigrantów. Nasze ustalenia pomogą poszczególnym krajom na dokładniejsze oszacowanie napływu migrantów, a zarazem wskazują członkom OECD, że poprzez poprawę jakości środowiska można przyciągnąć więcej emigrantów.

Microstructural Damage Characteristic of a Layer-to-Layer Three-Dimensional Angle-Interlock Woven Composite Under Quasi-Static Tensile Loading

Ma Qian, Wang Ke, Wang Shu-Dong, Chen Hong-Wu, Jin Li-Min, Liu Hua, Qin Xiao

Autex Research Journal

2020

Vol. 20, no. 2

121--127

Three-dimensional angle-interlock woven composites (3DAWCs) are widely used for their excellent mechanical properties. The most significant feature is the existence of the undulated warp yarns along the thickness direction, which makes it interesting to study the mechanical properties in the warp direction. The quasi-static tensile behavior of a layer-to-layer 3DAWC along the undulated warp direction was studied by experimental and finite element analysis (FEA) methods. Based on the experimental results, the typical failure mode involving fibers, resin, and their interfaces was found. According to the FEA results, the stress concentration effect, key structural regions, and microstructural (yarn and resin) damage mechanism were obtained, which provided effective guidance for structural optimization design of the 3DAWC with stronger tensile resistance performance. In addition, the three-step progressive failure process of the 3DAWC under quasi-static tensile load was also described at the “yarn–resin” microstructural level.