• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.249-256
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• 2019

The 9Cr-1Mo ferritic-martensitic ODS steel is a promising structural material for the next generation nuclear power plants including fast reactors for application in reactor vessels and nuclear fuel. The ODS steel was cooled down by furnace cooling, air cooling, oil quenching and water quenching, respectively, after normalizing it at $1150^{\circ}C$ for 1 h and then tempering at $780^{\circ}C$ for 1 h. It is found that grain size, a relative portion of ferrite and martensite, martensitic lath configuration, behaviors of carbide precipitates, and hardness of the ODS steel are strongly dependent on a cooling rate. The grain size and martensitic lath width become smaller with the increase in a cooling rate. The carbides were precipitated at the grain boundaries formed between the ferrite and martensite phases and at the martensitic lath interfaces. In addition, the carbide precipitates become smaller and more widely dispersed with the increase in a cooling rate, resulting in that the faster cooling rate generated the higher hardness of the ODS steel.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.287-292
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• 2021

The article analyzes the impact of capital structure on the firm value of chemical companies listed on the stock market of Vietnam. Data was collected from the financial statements of 23 chemical firms listed on the Vietnam stock market from 2012 to 2019. Quantitative research method with regression model according to OLS, FEM, REM method is used; FGLS method is used to overcome the model's defects. In this research, firm value (Tobin's Q) is a dependent variable. Capital structure (DA), Return on assets (ROA), Asset turnover (AT), fixed assets (TANG), Solvency (CR), Firm size (SZ), Firm Age (AGE), and revenue growth rate (GR) are independent variables in the study. The analysis results show that the capital structure of firms in the chemical industry listed on the Vietnam stock market has an inverse correlation with firm value. Besides, firms with greater asset turnover, business size, and number of years of operation have lower firm value. This article helps corporate executives improve corporate value by adjusting their capital structure properly. Chemical firms adjusted their capital structure in the direction of gradually decreasing the debt ratio and gradually increasing equity. Firms use high debt, which has the effect of reducing the firm value of firms in the chemical industry.

• Advances in nano research
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• v.10 no.2
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• pp.139-150
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• 2021

In this study, phytochemicals present in Propolis Extract (PE) were employed as reducing and stabilizing reagents to synthesize silver nanoparticles. Three propolis-reduced silver nanoparticles (P-AgNPs1-3) were synthesized using increasing amounts of PE. P-AgNPs were treated with different cancer cells-lung (A549), cervix (HeLa) and colon (WiDr) - for 24, 48 and 72 h to evaluate their anti-proliferative activities. A non-cancerous cell type (L929) was also used to test whether suppressive effects of P-AgNPs on cancer cell proliferation were due to a general cytotoxic effect. The characterization results showed that the bioactive contents in propolis successfully induced particle formation. As the amount of PE increased, the particle size decreased; however, the size distribution range expanded. The antioxidant capacity of the particles increased with increased propolis amounts. P-AgNP1 exhibited almost equal inhibitory effects across all cancer cell types; however, P-AgNP2 was more effective on HeLa cells. P-AgNPs3 showed greater inhibitory effects in almost all cancer cells compared to other NPs and pure propolis. Consequently, the biological effects of P-AgNPs were highly dependent on PE amount, NP concentration, and cell type. These results suggest that AgNPs synthesized utilizing propolis phytochemicals might serve as anti-cancer agents, providing greater efficacy against cancer cells.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.275-283
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• 2022

This study aims to investigate the influence of internal factors on the bankruptcy risk of an enterprise through a sample of 439 companies listed on the Vietnamese stock exchange. The research collected secondary data from annual audited financial statements from 2008 to 2019 of listing companies. Using two different regression models with two dependent variables, six independent and control variables, we discovered that three of the model's six factors, namely return on total assets, current payment rate, and financial leverage, influence the risk of bankruptcy and account for 86.78% of the variations in firm bankruptcy risk. Financial leverage has the opposite effect on the Z-score index, increasing the risk of bankruptcy of listed firms. Return on total assets and current ratio have a positive impact on the Z-score index, reducing the risk of bankruptcy of listed companies. The findings also revealed that there is no evidence that the size of a corporation, its fixed asset investment ratio, or the size of an auditing firm have an impact on the Z-score index. These findings provide crucial evidence for business owners and managers, as well as shareholders making future capital investment decisions. Our findings can be applied to other businesses in Vietnam and similar jurisdictions.

• Resources Recycling
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• v.32 no.6
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• pp.34-44
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• 2023

In this work, column flotation using factorial design was performed for recovering high-grade molybdenite concentrate. First, the flotation concentrate from Samyang Mining Plant was regrinded to a mean size of 165, 116, 46.7, and 38.4 ㎛ for an increase of the liberation degree. Tests were carried out for various variables affecting column flotation, and then the concentrates with molybdenite grade and recovery of 98.3 % and 95.28 % were obtained, respectively. Also, regression was performed using the statistical analysis program (SPSS 25) with the factorial design and experimental data on particle size, flow wash-water velocity and depressant that affect high grade. From the results, a model equation was derived to predict the molybdenite grade (MG) and recovery (MR) with the relationship between column flotation variables. Factors such as depressant concentration + wash-water velocity and particle size + depressant concentration + wash-water velocity were smaller than the significance level (0.05) and had a significant effect on the dependent variable, grade, and in the recovery model, only particle size and wash-water velocity factors affected the dependent variable, recovery.

• The Journal of Fisheries Business Administration
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• v.28 no.2
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• pp.1-18
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• 1997

The purpose of this study is to investigate empirically the characteristics of financial structure by using 76 fisheries corporations in Korea, and to suggest implications of the empirical results for government's financial policy for fisheries corporations. For the empirical test, we choose the following factors as the explanatory variables of cross-sectional regression analysis:firm-size(SIZE), collateral value of assets(TFATA), business risk(BRISK), growth(GROWTH), effective tax(ET), profitability(PROFIT). Two different debt ratios are used as dependent variables. One is defined as the ratio of total debt to total assets and the other is as that of long-term debt to total asset in terms of book value. The sample consists of 76 fisheries firms and sample period is 14 years from 1982 till 1995. From the results of cross-sectional regression analysis, the adjusted R$^2$values were high, 16∼79% and the overall F values indicated to be statistically significant. The results of cross sectional regression analysis show that the characteristics of financial structure fur fisheries corporations are as follows ; (1) Firm-size and collateral value of assets are the major factors of financial structure for fisheries corporations. That is, the larger firm-size the higher is debt ratio. This means that financial institutions conventionally lend more collateral loans with fixed assets like land, building rather than management capacities or credits. (2) To be consistent with a pecking-order theory, the higher is profitability the lower is debt ratio in fisheries corporations. (3) Corporations with high effective tax rate have lower financial leverage. Although the empirical results are inconsistent with traditional static trade-off theory, we think it would be attributed to government's various tax shelterings for fisheries which are likely to reduce tax shield effect of interests.

• Advances in concrete construction
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• v.6 no.3
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• pp.245-268
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• 2018

The numerical investigations have been carried out on deep beam with opening subjected to static monotonic loading to demonstrate the accuracy and effectiveness of the finite element based numerical models. The simulations were carried out through finite element program ABAQUS/CAE and the results thus obtained were validated with the experiments available in literature. Six simply supported beams were modelled with two square openings of 200 and 250 mm sides considered as opening at centre, top and bottom of the beam. In order to define the material behaviour of concrete and reinforcing steel bar the Concrete Damaged Plasticity model and Johnson-Cook material parameters available in literature were employed. The numerical results were compared with the experiments in terms of ultimate failure load, displacement and von-Mises stresses. In addition to that, seventeen beams were simulated under static loading for studying the effect of opening location, size and shape of the opening and depth, span and shear span to depth ratio of the deep beam. In general, the numerical results accurately predicted the pattern of deformation and displacement and found in good agreement with the experiments. It was concluded that the structural response of deep beam was primarily dependent on the degree of interruption of the natural load path. An increase in opening size from 200 to 250 mm size resulted in an average shear strength reduction of 35%. The deep beams having circular openings undergo lesser deflection and thus they are preferable than square openings. An increase in depth from 500 mm to 550 mm resulted in 78% reduced deflection.

• Journal of Labour Economics
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• v.37 no.1
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• pp.1-28
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• 2014

We use a set of Korea panel data to estimate effects of legal working hours reduction on actual hours worked and employment effects, through panel econometrics methods. Taking account of sequential decrease in legal hours worked since 2004, we estimate the relationship between legal and actual working hours by size of industries. It is found that one hour reduction of legal hours per week caused 0.44 to 1.05 actual hours worked on average per week, depending on different industrial sizes. Also, estimated employment effects were not unanimously determined, rather they turn out to be clearly size-dependent, which provide different results from exiting literature. Our analysis proposed in this work can be restrictive as, for instance, there is significant lack of data for foreign workers, particularly in the small-sized industries. Subsequent empirical analysis is expected.

• Advances in nano research
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• v.12 no.5
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• pp.467-482
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• 2022

In the current work, static and free torsional vibration of functionally graded (FG) nanorods are investigated using Fourier sine series. The boundary conditions are described by the two elastic torsional springs at the ends. The distribution of functionally graded material is considered using a power-law rule. The systems of equations of the mechanical response of nanorods subjected to deformable boundary conditions are achieved by using the modified couple stress theory (MCST) and taking the effects of torsional springs into account. The idea of the study is to construct an eigen value problem involving the torsional spring parameters with small scale parameter and functionally graded index. This article investigates the size dependent free torsional vibration based on the MCST of functionally graded nano/micro rods with deformable boundary conditions using a Fourier sine series solution for the first time. The eigen value problem is constructed using the Stokes' transform to deformable boundary conditions and also the convergence and accuracy of the present methodology are discussed in various numerical examples. The small size coefficient influence on the free torsional vibration characteristics is studied from the point of different parameters for both deformable and rigid boundary conditions. It shows that the torsional vibrational response of functionally graded nanorods are effected by geometry, small size effects, boundary conditions and material composition. Furthermore, for all deformable boundary conditions in the event of nano-sized FG nanorods, the incrementing of the small size parameters leads to increas the torsional frequencies.

• Membrane Journal
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• v.26 no.5
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• pp.372-380
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• 2016

The present paper reports the effect of precursor alumina particle size on pore structure and single gas permeation properties of tubular ${\alpha}$-alumina supports, prepared by a combined process of slip casting and sintering. Pore diameter of as-prepared ${\alpha}$-alumina support was highly dependent on precursor ${\alpha}$-alumina particle size. Although, increase in the precursor particle size increases the pore diameter, but the porosity of ${\alpha}$-alumina support mainly control by sintering temperature. Sintering studies reveal that as sintering temperature increased porosity of support decreased. Single gas permeance results indicate that permence is proportional to the square of pore diameter and linearly to porosity. These dependencies revealed that gas permeation trough as-prepared ${\alpha}$-alumina support was governed by viscous flow mechanism. The present announces that precursor ${\alpha}$-alumina particle size and sintering temperature are key parameters to control gas permeantion properties of ${\alpha}$-alumina supports.