Bioactive materials are those that cause a number of interactions at the biomaterial-living tissue inter-face that result in the evolution of a mechanically strong association between them. For this reason, an implantable material’s bioactive behavior is highly advantageous. Silicate glasses are encouraged to be used as bioactive glasses due to their great biocompatibility and beneficial biological effects. The sol-gel method is the most effective for preparing silicate glasses because it increases the material’s bioactivity by creating pores. Glass densities are altered by the internal network connectivity between network formers and network modifiers. The increase in the composition of alkali or alkaline oxides reduces the number of bridging oxygens and increases the number of non-bridging oxygens by retaining the overall charge neutrality between the alkali or alkaline cation and oxygen anion. Higher drying temperatures increase pore densities, while the melt-quenching approach encourages the creation of higher density glasses. Band assignments for the BAG structure can be explained in detail using Fourier Transform Infrared (FTIR) and Raman spectroscopic investigations. Raman spectroscopy makes it simple to measure the concentration of the non-bridging oxygens in the silica matrix.
In the current context of China’s vigorous development of its high-speed rail (HSR) network to accelerate the realization of connectivity, which is the aim of the “Belt and Road” initiative, it is crucial to study how the specific opening of HSR enhances enterprise human capital investment efficiency. Using a multiple-time-point difference-in-differences (DID) regression model, we empirically study data from listed Chinese companies. An HSR opening can promote the efficiency of an enterprise’s human capital investment. We further explore the relationship between HSR and a company’s human capital investment, by considering the moderating effects of firm property rights and foreign shareholding. Our findings indicate that these factors can enhance the impact of HSR on the efficiency of firms’ investments in human capital. Finally, to ensure the reliability of our experimental findings, we employed a combination of propensity score matching and the DID methodology. The findings of this study offer empirical evidence that can inform enterprise management strategies and provide valuable insights for policymakers seeking to promote economic growth.
Agriculture is an industry that plays an essential role in economic development towards eliminating poverty issues, but foreign direct investment (FDI) inflows to this sector remain modest in Vietnam. This study analyzed the determinants of foreign direct investment in the agricultural sector into the Southern Key Economic Zone (KEZ) of Vietnam, which is considered the foreign direct investment magnet of Vietnam, but its FDI inflows into the agricultural sector have been consistently low, and has shown a downward trend in recent years. The study was based on a sample of 129 foreign investors of a total of 164 multinational enterprises (MNEs) in the agricultural sector, including representatives of the Board of Directors and representatives at the department level. The Partial Least Squares Structural Equation modeling (PLS-SEM) approach was used to test the hypotheses. Findings indicated that FDI attraction policies have the strongest impact on FDI inflows. This was followed by infrastructure, regional agriculture policies, public service quality, natural conditions, and human resources. This study suggests policy recommendations to improve foreign direct investment inflows into the agricultural sector of the Southern Key Economic Zone (KEZ) of Vietnam.
Local scour, a complex phenomenon in river flows around piers with movable beds, can damage bridge piers during high floods. Predicting scour depth accurately is vital for safety and economic reasons, especially for large bridges. This study using hydraulic flume laboratory experiments compared diamond, square, and elliptical pier models of different sizes under steady clear-water conditions considering different flow rates and discharge levels to identify the most efficient shape with less local scour. Local scour, a complex phenomenon in three-dimensional flow around piers in rivers with movable beds, can lead to detrimental effects on bridge piers due to high flood velocities. Accurate prediction of scour depth is crucial for economic and safety reasons, especially for large bridges with complex piers. Hydraulic engineers are keen on forecasting the equilibrium scour depth. To achieve this, laboratory testing compared diamond, square, and elliptical pier models under steady clear-water conditions to identify the most efficient pier shape with less local scour. This research provides valuable insights for optimizing pier design to enhance bridge stability and resilience against scour-induced risks. A variety of configurations, including different sizes and shapes of piers were experimented with in the flume using diamond, square, and elliptical shapes. The test results showed that the local scour depth around elliptical piers was around 29.16% less, and around diamond piers, it was approximately 16.05% less compared to the scour depth observed around square piers with the same dimensions. The researchers also observed distinct patterns of scouring around different pier shapes. Specifically, the square-shaped piers displayed the highest level of scouring depth, that is, 48 mm, followed by the diamond-shaped pier which experienced a scouring depth of 48 mm while the elliptical-shaped piers experienced the least amount of scouring depth, that is, 34 mm. The test results also demonstrated that pier size significantly influences scouring, with an increase in pier size from 3 × 3 cm2 to 5 × 5 cm2 leading to a rise in scour depth by 26.04%. Moreover, this study findings also elucidated that an increase in flow results in an increase of in scouring depth i.e., elevating the discharge from 0.0026 cumecs to 0.0029 cumecs led to a 28.13% increase in scouring depth for the identical pier size. These findings provide valuable insights into the hydraulic behavior of various pier shapes and can aid in the optimization of bridge design and hydraulic engineering practices. The investigations further revealed that local scouring is sensitive not only to pier dimensions but also to other critical parameters, including flow rate, time of exposure, and the size of a pier.
COVID-19 has presented considerable challenges to fiscal budget allocations in developing countries, significantly affecting decisions regarding number of investments in the transport sector where precise resource allocation is required. Elucidating the long-term relationship between public transport investment and economic growth might enable policymaker to effectively make a decision in regard to those budget allocation. Our paper then utilizes Thailand as a case study to analyze the effects on economic growth in a developing country context. The study employs Cointegration and Vector Error Correction Model (VECM) techniques to account for long-term correlations among explanatory variables during 1991–2019. The statistical findings reveal a significantly positive correlation between transport investment and economic growth by indicating an increase of 0.937 in economic growth for every one-percent increment in transport investment (S.D. = 0.024, p < 0.05). This emphasizes the potential of expanding the transport investment to recover Thailand’s economy. Furthermore, in terms of short-term adjustments, our results indicate that transport investment can significantly mitigate the negative impact of external shocks by 0.98 percent (p < 0.05). These findings assist policymakers in better managing national budget allocations in the post-Covid-19 period, allowing them to estimate the duration of crowding-out effects induced by shocks more effectively.
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