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Ownership Structure and Dividend Policy of Vietnamese Enterprises after the Global Financial Crisis
Pham,Quoc Viet,Luong,Quoc Trong Vinh,Tran,Bao Vy 한국유통과학회 2019 KODISA ICBE (International Conference on Business Vol.2019 No.-
The paper examines the impact of ownership structure on the dividend policy of listed companies in the Vietnam stock market after the global financial crisis. The sample uses panel data including 91 corporates listed on the Ho Chi Minh City Stock Exchange (HOSE) for 2009-2015. The results of the study show that public ownership and domestic private ownership are positive correlated with dividend payout ratio, while the effect of foreign ownership on dividend policy is not significant. This result could provide an important implication on the orientation of restructuring state-owned enterprises and attracting foreign investment in Vietnam stock market in the future.
Evaluation of physicochemical and biological properties of python fat (Python bivittatus)
Pham Thi Quyen,Le Pham Tan Quoc 한국식품저장유통학회 2023 한국식품저장유통학회지 Vol.30 No.5
The main aim of this study was to determine python fat’s several physicochemical properties, including dimensions, color, structure, acid value (AV), saponification value (SV), density, and recovery efficiency. The optimum yield obtained was approximately 80.40% at 180℃ for 60 min with an AV of 0.3366 and SV of 179.56 mg KOH/g. Fatty acids, comprising oleic acid (72.462%), palmitic acid (26.243%), linolenic acid (0.835%), and myristic acid (0.459%), were identified using gas chromatography-mass spectrometry (GC-MS). The python fat had a very weak antioxidant capacity and almost no antibacterial ability with gram-positive (Staphylococcus aureus - ATCC 25923 and Bacillus cereus - ATCC 10876) and gram- negative (Escherichia coli - ATCC 25922 and Salmonella enterica - ATCC 35664) bacteria (used the paper disc diffusion method for antibiotic susceptibility testing). Moreover, python fat is considered to be very resistant to high temperatures.
Investigating texture and mechanical properties of Asian pear flesh by compression tests
Quoc Thien Pham,Nai-Shang Liou 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8
In this study, texture and mechanical properties of Fengshui and Shingo pears were investigated by using double-bite compression tests. Texture properties such as hardness, fracturability, cohesiveness and springiness were determined and the relationships among selected sensory texture attributes were examined. Furthermore, the more objective mechanical properties such as elastic modulus, fracture and compression strength of pear were also investigated. The test results revealed that the hardness, fracturability and chewiness of Shingo are significantly higher than those of Fengshui. Besides, the strain at fracture of Shingo pear is 70 % higher than that of Fengshui and the stress of Shingo at fracture is 3 times higher than that of Fengshui. This understanding can be used to assist in the selection of superior variety of pears.
Evaluation of Press Formability of Pure Titanium Sheets
Pham, Quoc Tuan,Kim, Young Suk Trans Tech Publications, Ltd. 2016 Key Engineering Materials Vol.716 No.-
<P>Commercially pure titanium (CP Ti) has been actively used in plate heat exchangers due to its light weight, high specific strength, and excellent corrosion resistance. However compared with automotive steels and aluminum alloys, only limited research has been conducted on the plastic deformation characteristics and press formability of CP Ti sheets. In this study, the mechanical properties, including the anisotropic property and the stress-strain relation, of the CP Ti sheet are clarified in relation to press formability. A new proposed strain hardening model, Kim-Tuan equation, is successful in perfectly describing the stress evaluation for strain increment of this material during strain path. The forming limit curve (FLC) of the CP Ti sheet as a criterion for press formability was experimentally evaluated by punch stretching testing and analytically predicted via Hora’s modified maximum force criterion. The predicted FLC based on the Kim-Tuan strain hardening equation and the appropriate yield function correlates well with the experimental results of the punch stretching test.</P>
Study on Pad Cutting Rate and Surface Roughness in Diamond Dressing Process
Quoc-Phong Pham,Chao-Chang A. Chen 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.12
Diamond dressing process has an important role in the elimination of scrap materials on the pad surface and regeneration of the pad surface topography before and after Chemical Mechanical Planarization/Polishing (CMP) process for integrated circuit (IC) fabrication. During diamond dressing process, distributions of cutting locus and overlap cutting of diamond grits usually work as a datum surface for pad surface planarization and uniform pad asperities. This paper proposes a novel view to predicting the distribution of pad cutting rate (PCR) and surface roughness based on cutting length and overlap cutting locus. The geometrical model of diamond dressing on the pad has been built and CMP tool parameters are used for the simulation of cutting length and overlap distribution. The distribution of PCR and predict surface roughness is calculated on each pad zone. Simulation results presented a high PCR and roughness is observed in center zones. The verified experiment is in agreement with simulation results where high PCR and roughness is near the center zones, which cause the shape of the pad surface to be concave. The results of this study can be further applied for prediction and optimization of diamond dressing design and improvement of dressing process.
1-D CNN deep learning of impedance signals for damage monitoring in concrete anchorage
Quoc-Bao Ta,Quang-Quang Pham,Ngoc-Lan Pham,Jeong-Tae Kim Techno-Press 2023 Structural monitoring and maintenance Vol.10 No.1
Damage monitoring is a prerequisite step to ensure the safety and performance of concrete structures. Smart aggregate (SA) technique has been proven for its advantage to detect early-stage internal cracks in concrete. In this study, a 1-D CNN-based method is developed for autonomously classifying the damage feature in a concrete anchorage zone using the raw impedance signatures of the embedded SA sensor. Firstly, an overview of the developed method is presented. The fundamental theory of the SA technique is outlined. Also, a 1-D CNN classification model using the impedance signals is constructed. Secondly, the experiment on the SA-embedded concrete anchorage zone is carried out, and the impedance signals of the SA sensor are recorded under different applied force levels. Finally, the feasibility of the developed 1-D CNN model is examined to classify concrete damage features via noise-contaminated signals. The results show that the developed method can accurately classify the damaged features in the concrete anchorage zone.
Quoc Tuan Pham,김영숙 대한금속·재료학회 2017 METALS AND MATERIALS International Vol.23 No.2
This study aims to determine the plastic deformation characteristics of aluminum 5052-O based on non-associatedflow rule. To achieve this goal, a new strain hardening model named as Kim-Tuan hardening modelis proposed to perfectly describe the stress-strain relation of the studied material in terms of the uniaxial tensiletest and to predict the material’s post-necking behavior. Additionally, the plastic behaviors of AL5052-O sheetare described by two approaches: the associated flow rule with YLD2000-2d yield function and the nonassociatedflow rule with Hill's quadratic function (NAFR-Hill48). The parameters of these functions werederived from the material properties that were obtained from uniaxial tensile tests and bulge test. The flow curvebased on Kim-Tuan model and plastic behaviors obtained from two above-mentioned approaches were importedinto a finite element analysis code to simulate the hydraulic bulge test for this material to confirm the precisionof material characteristics achieved before. The simulation results based on the NAFR-Hill48 match wellwith the experiment results of bulge test while the YLD2000-2d provides highly accurate predictions foranisotropy of this material.
APPLICATION OF A GRAPHICAL METHOD ON ESTIMATING FORMING LIMIT CURVE OF AUTOMOTIVE SHEET METALS
Quoc Tuan Pham,Jinjae Kim,The-Thanh Luyen,Duc-Toan Nguyen,김영석 한국자동차공학회 2019 International journal of automotive technology Vol.20 No.Supp
In the automotive engineering community, the modified maximum force criterion proposed by Hora and coworkers is considered acceptable for theoretically estimating the forming limit curve (FLC) of sheet metals. Based on this criterion, a graphical method is proposed to simplify evaluation of the FLC. This paper investigates the proposed graphical method in a special case by using a power-hardening law and the Mises yield function, which leads to an explicit expression of the critical strains according the strain paths. The FLC of a DP590 sheet estimated using the proposed method is compared with that estimated using existing analytical methods. The proposed method provides the best prediction of the FLC of the tested material. For verification, the calculated FLC is then adopted into the finite-element method to predict the punch stroke at fracture of several notched specimens subjected to Nakazima tests. The good agreement between the predicted and experimentally determined values of the punch strokes verifies the ability and potential of the proposed method in industrial engineering.