Experimental and Numerical Study on the Strain Behavior of Buried Pipelines Subjected to an Impact Load

Long-distance oil and gas pipelines are inevitably impacted by rockfalls during geologic hazards such as mud-rock flow and landslides, which have a serious effect on the safe operation of pipelines. In view of this, an experimental and numerical study on the strain behavior of buried pipelines under the impact load of rockfall was developed. The impact load exerted on the soil, and the strains of buried pipeline caused by the impact load were theoretically derived. A scale model experiment was conducted using a self-designed soil-box to simulate the complex geological conditions of the buried pipeline. The simulation model of hammer&ndash soil&ndash pipeline was established to investigate the dynamic response of the buried pipeline. Based on the theoretical, experimental, and finite element analysis (FEA) results, the overall strain behavior of the buried pipeline was obtained and the effects of parameters on the strain developments of the pipelines were analyzed. Research results show that the theoretical calculation results of the impact load and the peak strain were in good agreement with the experimental and FEA results, which indicates that the mathematical formula and the finite element models are accurate for the prediction of pipeline response under the impact load. In addition, decreasing the diameter, as well as increasing the wall thickness of the pipeline and the buried depth above the pipeline, could improve the ability of the pipeline to resist the impact load. These results could provide a reference for seismic design of pipelines in engineering. Document type: Articl

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Financial asset allocation duality and enterprise upgrading: empirical evidence from the Chinese A-share market

Abstract This study selects the financial data of Chinese non-financial listed companies from 2012 to 2021 as the research sample and empirically examines in detail the impact of financial asset allocation on enterprise upgrading and its mechanism. The study finds that financial assets have a dual influence on enterprise upgrading. Short-term financial assets provide the necessary funds for production activities, thus promoting enterprise upgrading. Long-term financial assets crowd out the funds needed for production activities and thus inhibit enterprise upgrading, resulting in an inverted U-shaped relationship between financial assets and enterprise upgrading. Mechanism testing revealed that risk-taking capacity and earnings persistence are important ways in which financial assets affect enterprise upgrading. In addition, the impact of financial assets on enterprise upgrading differs for different types of financial assets. The financial asset significantly impacts the upgrading of over-indebtedness, non-state-owned, and high financing constraints enterprises. This study enriches the research literature on financial assets and enterprise upgrading and provides new micro evidence for understanding the impact of financial assets on the enterprise upgrading of listed companies

How Does Transportation Infrastructure Improve Corporate Social Responsibility? Evidence from High-Speed Railway Openings in China

The socioeconomic impacts of infrastructure investment are worth examining in both academic and practical areas. Regarding Chinese high-speed railway construction, the existing literature mainly focuses on the macro-economic level consequences of high-speed railway openings, leaving the micro-economic level impacts commonly untested. Using archival data of Chinese listed companies from 2009 to 2018 and the difference-in-difference (DID) approach, this paper examines the influential effect of Chinese high-speed railway openings on corporate social responsibility (CSR) performance. Empirical results show that high-speed railway openings can significantly improve Chinese listed companies’ CSR performance, and this positive effect is more salient when companies are experiencing lower information transparency. Mediating effect tests illustrate that the increased investor site visits caused by high-speed railway openings are one internal mechanism behind the main connection. Overall, from a micro-level perspective, this article provides additional evidence on the socioeconomic impact of transportation infrastructure investments

Public-Private Partnership Transportation Investment and Low-Carbon Economic Development: An Empirical Study Based on Spatial Spillover and Project Characteristics in China

As the most widely used investment mode of transportation infrastructure in China, PPP has been regarded as an effective institutional tool by the Chinese government for the construction of efficient and sustainable transportation infrastructure, promoting high-quality economic development. In order to evaluate the economic sustainability of PPP, this paper innovatively takes the low-carbon economy as the research perspective and uses 276 cities of China from 2006 to 2018 as samples to comprehensively investigate the impact of transportation PPP investment on the low-carbon economy from the diversified dimensions of the overall effect, spatial effect, mediating effect, heterogeneous effect, lagged effect, and PPP project-level characteristics. The results show that: (1) transportation PPP investment markedly promotes low-carbon economic development in China, which is manifested as the dual improvement effects of benefits and efficiency; (2) transportation PPP investment has a positive spatial spillover effect that can promote the low-carbon economic development of neighboring cities; (3) transportation PPP investment can promote low-carbon economic development by promoting the upgrading of industrial structures, and furthermore has a spatial transmission mechanism; (4) impacts of transportation PPP investment in different subsectors are significantly heterogeneous; (5) transportation PPP investment has a continuous and stable impact on promoting the low-carbon economy in China; (6) the participation of state-owned enterprises and listed companies in PPP projects has a significant positive impact, and state-owned capital is more effective in projects with relatively large scale. All these provide reliable evidence for the far-reaching significance and practical value of transportation PPP investment on sustainable low-carbon economic development

Enterprises’ R&D Investment, Venture Capital Syndication and IPO Underpricing

Based on the data of companies that got ChiNext listed from 2009 to 2018, this paper empirically studies the relationship among R&D investment, venture capital (VC) syndication and IPO underpricing. It is found that there is a significant positive correlation between R&D investment and IPO underpricing, indicating that the higher the R&D investment is, the higher the IPO underpricing degree is; the intervention of VC syndication plays a role of “adverse selection” instead of giving play to its advantages of sharing information, which intensifies the positive correlation between R&D investment and IPO underpricing. Further analysis shows that the reputation of the leading VC in syndication can play a negative regulating role; the higher the reputation of the leading VC is, the more it can play the “certification effect”, reduce the information asymmetry caused by R&D investment, therefore alleviating the IPO underpricing caused by R&D investment

Institutional Investor Shareholdings and Corporate Social Responsibility – Evidence from Tourism Related Industries in China

Using data from Chinese A-share listed companies in tourism related industries from 2009 to 2018, this paper examines the influence of institutional investor shareholdings on corporate social responsibility (CSR) performance. Results show that: First, institutional investor shareholdings can significantly improve CSR performance of tourism related public companies in China. After implementing robustness test, this positive relationship remains solid. Second, the positive effect of institutional investor shareholdings is significantly unbalanced regarding different CSR dimensions, with the most salient influence in promoting companies’ social welfare contributions. And third, the impact of institutional investor shareholdings can be strengthened when listed companies are ultimately controlled by the state

The Influence of the Air Cargo Network on the Regional Economy under the Impact of High-Speed Rail in China

There is little research on the impact of air cargo networks on regional economic development, which is especially notable considering that Chinese airlines gradually adjusted their networks after the introduction of high-speed rail (HSR). This empirical study aims to fill this research gap. Firstly, we used the Ordinary Least Squares (OLS) method to study the effect of the air cargo network on the regional economy. The results show that, in eastern and central China, the higher the clustering coefficient of the domestic air cargo network, the more significant their promotion effect becomes on the GDP per capita, with cities in eastern China benefitting the most from this effect. However, for super-scale cities, the clustering coefficient of the domestic air cargo network has a significant negative effect on the GDP per capita, which is likely because both the air and HSR passenger services crowd out the development opportunities for air cargo. Secondly, we applied the Difference-in-Difference (DID) method in order to measure the impact on the regional economy caused by air cargo under the impact of HSR. The results show that the aviation network adjusted for the impact of HSR produces heterogeneous effects on cities for different regions and scales, and that the international aviation network has greater impacts on cities than the domestic network. In eastern China, HSR and air cargo (both international and domestic networks) promote economic growth simultaneously; in central China, only domestic air cargo has a positive effect on the regional economy; in western China, neither HSR nor air cargo has an obvious effect on the regional economy. Policy implications—such as encouraging the cooperation of HSR and civil aviation—are discussed, and could help bring the functions of the air cargo network in regional economic development into full play