This research aims to investigate the effects of dividend policies on a firms’ financial performance. The paper explores the research gap and then builds a research model using ROA, ROE, and Tobin’s Q as dependent variables, dividend rate and decision of dividend payment as independent variables. The paper collected data and financial statements of 450 firms that are listing on the stock market of Vietnam from 2008 to 2019. The analysis results indicate that the decision of dividend payment has negative impact to Vietnamese firms measured by accounting-based performance but this improve market expectation on firms. In addition, the paper finds that Vietnamese firms are offering low dividend rate which has a positive impact on accounting-based performance but a negative effect on market expectation. This paper proposes some instructive recommendations based on the findings, including a more appropriate model of dividend policies, a lower dividend rate, and clear decision of dividend payment.

This study examines the factors that affect firm's liquidity in manufacturing companies listed in Vietnam. Factors studied include the board size, the board independence, the firm size, the firm age, and its return. We use different metrics to measure firm's solvency status, including the cash ratio, the quick ratio, and the cash conversion cycle. Accordingly, three econometric models are built to test hypotheses proposed by researchers in order to explain the relationship between the five factors above and liquidity's measures. The study used the data set of manufacturing companies listed on the Ho Chi Minh City Stock Exchange in the period from 2015 to 2019. The final sample group comprises 139 firms with 633 observations. The results show that in manufacturing firms, while the cash ratio and the quick ratio are positively associated to the board size, the board independence, and the firm's profitability, the net operating cycle is negatively correlated to the board size, the firm size, the board independence, and the profitability. Therefore, larger firms with larger board size and more independent members can help to improve capital management efficiency.There is no evidence for the relationship between the firm age and solvency measurements, between cash conversion cycle and firm's profitability.

This research focused on exploring capital structure that would have an impact on the Vietnamese company’s profitability. Theoretically, we apply agency theory which mentions the separation of ownership and management, which leads to the problem when the managers act in their own interests rather than the owner’s interest. We built a research model, and the quantitative data was clarified thanks to the regression model with the data given by 300 Vietnamese firms for the period from 2012 to 2018. The findings indicated that firm profitability, represented by Return on Equity (ROE) and Return on Assets (ROA), was associated with liquidity and debt. In detail, it was indicated that there would be a positive relationship between liquidity and profitability of Vietnamese entrepreneurs, while there was a negative relationship between long-term debt and profit maximization. Moreover, the short-term loan also has a positive impact on the firm’s profitability in the context of Vietnam. These preliminary outcomes negated some previous research, confirming that the higher the leverage, the better the firm’s profitability. The difference in findings may provide information about a dynamic Vietnam market as well as the financial environment that require changes in the capital structure to gain the optimal profit.

Nowadays, polycrystalline diamond compact (PDC) drill bits are widely used in the oil and gas industry when drilling in soft rocks. However, parameters used for the PDC bit are usually based on the instructions of the drill manufacturer with a very wide adjustment range. Therefore, it is necessary to have a specific formula in order to determine the rate of penetration parameter (ROP) for the PDC bit in evaluating the influence of the parameters, rock mechanical properties and other parameters on the rate of penetration parameter (ROP). From there, it gives reasonable parameters and improves the design of the PDC bit to improve drilling efficiency. The article applies theoretical analysis method and Dalamber's principle to illuminate and build up the impact force model for PDC bits in the rock destruction process. From the impact force model, a formula to determine ROP for PDC bits was proposed. Finally, the authors applied the research results to the actual data obtained from the Nam Rong - Doi Moi oil field. The formula for determining the rate of penetration parameter (ROP) for the PDC bit that the authors have built has high accuracy and can be applied to many different rock.