The development of advanced creep constitutive equations for high chromium steel P91 at low stress range

Diffusion dominates the creep deformation at low stress range for high chromium steel P91. Brittle creep fracture is caused by cavity nucleation, growth and coalescence of cavities and large precipitates (Laves phase and M23C6) at grain boundary under low stress range. At low stress range, a linear relation between strain at failure and different stresses has been described. Moreover, the minimum strain rate is also proportional to the different stresses

Review on the current state of developing of advanced Creep Damage Constitutive Equations for high Chromium Alloy

This paper presents a review of developing of creep damage constitutive equations for high chromium alloy (such as P91 alloy). Firstly, it briefly introduces the background of creep damage for P91 materials. Then, it summarizes the typical creep damage constitutive equations developed and applied for P91 alloy, and the main deficiencies of KRH (Kachanov-Robatnov-Hayhurst) type and Xus type constitutive equations. Finally it suggests the directions for future work. This paper contributes to the knowledge for the developing creep damage constitutive equations for the specific material

Preliminary analysing of experimental data for the development of high Cr Alloy Creep damage Constitutive Equations

This conference paper presents the current research of preliminary analysing of experimental data for the development of high Cr Alloy Creep damage Constitutive Equations (such as P91 alloy). Firstly, it briefly introduces the background of general creep deformation, rupture and continuum damage mechanics. Secondly, it illustrates the constitutive equations used for P91 alloy or its weldment, especially of the form and deficiencies of two kinds of most widely used typical creep damage constitutive equations Kachanov-Rabotnov-Hayhurst (KRH) and Xu’s formations. And then, the methodology for development of new set constitutive equation proposed by Xu (2004) has been followed in this research. Fourthly, there is a critically analysis of the specific experiment data for P91 alloy and its weldment. Afterwards, the specific requirements for developing a new set constitutive equation have been reported

Analyzing the characteristics of the cavity nucleation, growth and coalescence mechanism of 9Cr-1Mo-VNb steel (P91) steel

Creep damage is one of the serious problems for the high temperature industries and computational approach (such as continuum damage mechanics) has been developed and used, complementary to the experimental approach, to assist safe operation. However, there are no ready creep damage constitutive equations to be used for predicting the lifetime for this type of alloy, particularly for low stress. This paper presents an analysis of the cavity nucleation, growth and coalescence mechanism of 9Cr-1Mo-VNb steel (P91 type) under high and low stress levels and multi-axial stress state

Harmony in diversity:Can One Belt One Road initiative promote China’s OFDI?

This paper investigates the effect of the One Belt One Road (OBOR) initiative on China’s outward foreign direct investment (OFDI) using a dataset of all host countries for the period of 2010–2015. The employed econometric technique combines a difference-in-differences estimator with matching techniques. The results show that China’s OFDI in OBOR countries is about 40% higher than in non-OBOR countries. After the initiative, the OFDI from China increases by 46.2% in OBOR countries. However, after controlling for the heterogeneity across OBOR and non-OBOR countries using the matching approach, the significance of the increasing effect caused by the OBOR initiative disappears. We also find the OBOR initiative diminishes the resource-seeking motivation and improves the market-seeking motivation of China’s OFDI. Our results cast doubts on the infrastructure-led and institution-based strategy of the OBOR initiative, but support the boosting effect of the OBOR initiative on institutional cooperation and cultural convergence. Thus, the OBOR initiative is a sustainable continuation and development of the long tradition of economic, institutional, and cultural convergence with the OBOR countries, rather than a temporary policy shock

Heat treatment, microstructure and properties of 75Cr1 steel, for use in heavy loaded elements

This study aims to optimize the heat treatment of tool steel 75Cr1 which is used for heavy loaded elements in transmissions. A salt bath was used to quench and temper the steel at different temperatures. Mechanical tests and microstructural characterization were done to define the heat treatment parameters corresponding to the optimal performance of the elements. Optical microscopy, electron back scatter diffraction and x-ray diffraction were used to characterize the microstructure, while tensile tests and toughness tests were employed to determine the mechanical properties after different heat treatments. It was found that the yield strength decreases with increasing annealing temperature and that the toughness decreases with increasing annealing time and temperature. The changes of the mechanical properties are discussed in relation with the thermal treatment and the corresponding microstructures

The development of advanced creep constitutive equations for high chromium alloy steel (P91) at transition stress range

Creep damage is a time-dependent deformation in metals under a constant stress at high temperature condition. Since the 1980s, high chromium alloy steel P91 (9%Cr-1%Mo-0.25%V) is highly demanded in high temperature industries (Saha, 2003). Continuum damage mechanism is becoming a generic life assessment tool to predict the lifetime of materials at creep condition. The consitutive equations were proposed to predict the lifetime and creep behaviours of materials. The most widely used constitutive equations are simply called Kachanov-Rabotnov-Hayhurst (KRH) in the current research. The lifetime of high chromium alloy steel P91 has been overestimated by the extrapolation method from short-term creep tests (high stress) to long-term creep tests (lower stress). The definition of stress ranges depends on different materials and temperatures. The current researcher classifies the stress ranges into high stress range, transition stress range and low stress range with stress exponen

Search for the Lepton Flavor Violation Process J/ψ→eμJ/\psi \to e\mu at BESIII

We search for the lepton-flavor-violating decay of the $J/\psi$ into an electron and a muon using $(225.3\pm2.8)\times 10^{6}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider. Four candidate events are found in the signal region, consistent with background expectations. An upper limit on the branching fraction of $\mathcal{B}(J/\psi \to e\mu)< 1.5 \times 10^{-7}$ (90% C.L.) is obtained

Longitudinal evaluation of aflatoxin exposure in two cohorts in south-western Uganda

Aflatoxins (AF) are a group of mycotoxins. AF exposure causes acute and chronic adverse health effects such as aflatoxicosis and hepatocellular carcinoma in human populations, especially in the developing world. In this study, AF exposure was evaluated using archived serum samples from human immunodeficiency virus (HIV)-seronegative participants from two cohort studies in south-western Uganda. AFB1-lysine (AFB-Lys) adduct levels were determined via HPLC fluorescence in a total of 713 serum samples from the General Population Cohort (GPC), covering eight time periods between 1989 and 2010. Overall, 90% (642/713) of the samples were positive for AFB-Lys and the median level was 1.58 pg mg(-1) albumin (range = 0.40-168 pg mg(-1) albumin). AFB-Lys adduct levels were also measured in a total of 374 serum samples from the Rakai Community Cohort Study (RCCS), across four time periods between 1999 and 2003. The averaged detection rate was 92.5% (346/374) and the median level was 1.18 pg mg(-1) albumin (range = 0.40-122.5 pg mg(-1) albumin). In the GPC study there were no statistically significant differences between demographic parameters, such as age, sex and level of education, and levels of serum AFB-Lys adduct. In the RCCS study, longitudinal analysis using generalised estimating equations revealed significant differences between the adduct levels and residential areas (p = 0.05) and occupations (p = 0.02). This study indicates that AF exposure in people in two populations in south-western Uganda is persistent and has not significantly changed over time. Data from one study, but not the other, indicated that agriculture workers and rural area residents had more AF exposure than those non-agricultural workers and non-rural area residents. These results suggest the need for further study of AF-induced human adverse health effects, especially the predominant diseases in the region

Digital transformation in agricultural circulation: enhancing rural modernization and sustainability through technological innovation

IntroductionAs digital transformation accelerates globally, the digitalization of agricultural product circulation (DAPC) is becoming a key driver of rural revitalization and sustainable agricultural development.MethodsThis study introduces a digital agriculture product circulation index (DAPCI) to assess the level of digitalization in agricultural product circulation and the influence of digitalization on rural modernization in China. Additionally, this study develops a rural agricultural modernization development index (RAMDI) to measure the extent of modernization across 30 provinces (from 2012–2023). The entropy weight method and a spatial error model are applied to capture both direct and indirect effects.ResultsThe findings reveal that digitalization significantly enhances rural agricultural modernization (RAM), particularly in technologically advanced regions, with strong spatial spillover effects benefiting neighboring areas. The results further reveal that the digitalization of agricultural circulation positively correlates with improved rural economic development; green innovation and industrial structure optimization emerge as key mechanisms for driving both environmental sustainability and economic growth.DiscussionThis research contributes to understanding how digital tools can reshape agricultural practices, making those practices more resilient, efficient, and environmentally friendly. By demonstrating the impact of digitalization on rural agricultural sustainability, this study highlights the importance of integrated technological innovations and management strategies for advancing sustainable agricultural development and climate resilience in rural economies