Influence of area-to-volume ratios on dissolution characteristics and mechanical properties of acid-corroded sandstone

To study the effect of area-to-volume ratio on the dissolution and deterioration characteristics of sandstone in the static acid-rock reaction system, the HCl and H2SO4 solutions with pH=2 and 5 are selected as corrosion environments, and the different area-to-volume ratios are set by changing surface areas of sandstone. The effects of area-to-volume ratios on the physicochemical and mechanical properties of sandstone are studied. According to the acid-rock reaction theory, the effect of the area-to-volume ratio on the diffusion-dissolution mechanism during sandstone corrosion is analyzed. The results show that the sandstone mass loss rate and amount of substance of total cations are all related to the corrosion time as a power function. The area-to-volume is positively correlated with the dissolution rate constant and has little effect on the reaction order. The reaction order is less than one in different environments, indicating that the sandstone corrosion rate decreases gradually with soaking time. In the pH=2、5 HCl solution and pH=2 H2SO4 solution, the amount of substance of cation shows N(Ca2+) > N(Na+) > N(Mg2+) > N(K+), and in the pH=5 H2SO4 solution, it is N(Na+) > N(Ca2+) > N(Mg2+) ≈N(K+). The acid-rock reaction can be summarized as two mechanisms: diffusion control and chemical reaction control. The two control parameters are negatively correlated with the area-to-volume ratio and positively with the pH value of solutions. The parameter values in the H2SO4 solutions are slightly larger than the corresponding values in the HCl solutions. The interaction between sandstone and acid in different conditions is dominated by the chemical reaction. The area-to-volume ratio significantly influences diffusion more than the chemical reaction. The mechanical properties of sandstone are weakened after acid corrosion. The damage of sandstone under uniaxial compression can be divided into four stages: compaction, elastic deformation, plastic yielding and post-peak. The peak strength and elastic modulus decrease, the peak strain increases, the brittleness declines, and the ductility is enhanced. The larger the area-to-volume ratio, the more severe the sandstone deterioration is. Overall, the smaller the pH value of solutions, the more prominent the effects of the area-to-volume ratio on the dissolution characteristics and mechanical properties of sandstone are, which is more obvious in the HCl solutions than in the H2SO4 solutions. The finding can provide theoretical references for the safety assessment and disaster prevention of rock mass engineering under an acidic environment

A Gain-of-function TPC2 Variant R210c Increases Affinity to PI(3,5)P

Albinism is a group of inherited disorders mainly affecting skin, hair and eyes. Here we identify a de novo point mutation, p.R210C, in the TPCN2 gene which encodes Two Pore Channel 2 (TPC2) from a patient with albinism. TPC2 is an endolysosome and melanosome localized non-selective cation channel involved in regulating pigment production. Through inside-out recording of plasma membrane targeted TPC2 and direct recording of enlarged endolysosomal vacuoles, we reveal that the R210C mutant displays constitutive channel activation and markedly increased affinity to PI(3,5)

Environmental disclosure practices in mixed ownership models: A study of Chinese private enterprises.

Environmental information disclosure is critical avenue for stakeholders to gauge the fulfillment of corporate environmental responsibilities, as well as a key path for companies to gain social reputation and achieve sustainable development. To achieve both economic and social sustainability and improve the environmental information disclosure by private firms, this study delves into the impact mechanism and realization path of mixed ownership reform on environmental information disclosure among Chinese private enterprises listed between 2010 and 2020. Utilizing a panel fixed effect model, we scrutinize the interplay between state capital involvement and the disclosure of environmental information by private enterprises. Our findings reveal that state capital involvement may encourage private enterprises to disclose environmental information through resource allocation and governance improvements. The higher the shareholding ratio of state-owned participating shareholders, the more it helps private firms to disclose environmental information. State-owned shareholders play a pivotal role in the appointment of supervisors, directors, and executives, effectively improving corporate governance mechanisms and positively moderates how private companies with state-owned capital participate in disclosing environmental information. Moreover, the magnitude of media coverage and the public opinion pressure faced by private enterprises further amplify the influence of state-owned capital involvement on environmental information disclosure. Additionally, our research reveals that corporate profitability partially interplays with the effects of state-owned capital disclosure of environmental information by private companies. According to the research results, we recommend that the government proactively promote mixed ownership reform with private enterprises as the main participants, fully leveraging the resource advantages and influence of state-owned capital. At the same time, it is imperative to strengthen the governance effect of internal state-owned shareholders and external public opinion supervision in private enterprises. Enhancing profitability is also identified as a key driver for private enterprises to engage in more robust environmental information disclosure practices

Removal of malodorous organic sulfides with molecular oxygen and visible light over metal phthalocyanine

Organic sulfides are malodorous compounds in environment. In this work, deodorization of model substrates, methyl phenyl sulfide, 2-mercaptobenzoic acid and benzyl 2-propenyl sulfide, have been studied in an aerated methanolic aqueous solution under visible light irradiation (λ > 450 nm), using metal phthalocyanine sulfonate (MPcS, M = Al, Pd) as a photocatalyst. The result shows that all the representative sulfides could be efficiently oxidized, with concomitant formation of sulfoxide and sulfone as the main products. Kinetic study using sodium azide and benzoquinone as reactive species scavenger reveals that the sulfide oxidation is mainly initiated by singlet oxygen. It is also observed that the rate of sulfide oxidation increases with increasing the water content in the mixed solvent. Recycle experiments with immobilized PdPcS on organoclay or immobilized AlPcS on anionic resin demonstrates that the sensitizer could be repeatedly used, without significant loss in the photosensitization activity

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With an increasing number of heterogeneous shareholders participating in corporate governance in reality, the assumption of shareholder homogeneity in agency theory is gradually relaxing in the modern field of corporate governance. The policy of mixed ownership reform in China provides empirical evidence for studying heterogeneous shareholder governance. To fully understand the governance effects of non-state shareholders, we employ the ownership proportion held by non-state shareholders among the top ten shareholders and the appointment of directors as measures for non-state shareholder governance. Using a panel fixed-effect model from the perspective of state-owned enterprises (SOEs) party organizations, we examine the impact of non-state shareholder governance on the governance level of SOEs. The study reveals that non-state shareholder governance positively affects the governance level of SOEs, with board resolutions playing a crucial role in this relationship. When party members serve as directors, the governance effect of non-state shareholders is more significant. Based on the aforementioned research findings, we recommend further refining corporate governance measures for SOEs within the context of SOE reforms. It is advisable to optimize the party organizational governance structure and leverage the synergistic effects of non-state shareholder governance and party organizational governance. Advancing reforms along the Pareto improvement path will contribute to establishing a distinctive corporate governance system for Chinese SOEs.</div