Modelling and Experimental Validation of a VNT Turbocharger for Improving Performances of a Marine Diesel Generator Engine

This paper presents modelling and experimental validation for improving the performances of a marine diesel generator engine. Based on the diesel engine theory, the laws of conservation of energy, and the principle of movement of flow through turbocharger nozzle, a mathematical model of a real turbocharged engine was built, concentrating on the mathematic model of flow through nozzles. This model is simulated by Matlab/Simulink program, the results of simulation showed the relationships between the engine and the turbocharger, the turbine and the compressor, and between the nozzles and the turbocharger. The experiments were carried out to validate this model, the errors between the simulation and measure were acceptable. The measure and simulation results also determined that at the low load conditions (≤50% load) engine performances can be improved by adjusting nozzle opening degree (from fully opening to 90% and 80% opening)

SMALL POWER ENGINE FUELED WITH BIOGAS

Joint Research on Environmental Science and Technology for the Eart

Criblage virtuel sur grille de composés isolés au Vietnam

Criblage virtuel sur grille de composés isolés au Vietna

Calculation of turbulent diffusion jets under effects of gravity and moving surrounding air

The basis theory for the turbulent diffusion of jet and flame has been presented previously [1, 2]. But that one applies only in quiet surrounding air with the effects of buoyancy neglected. In the present paper, the theory is developed further by establishing an integral model for a jet in more general conditions with variable inclined angles, under effects of gravity and surrounding air velocity in any direction compared to the jet axis. The system of equations is closed by turbulence k-E model and is solved by 4th order Runge-Kutta method. In the first stage, the model is applied to predict the velocity field, the concentration field and with development of a 0.3 m diameter jet

Cultural evolution in Vietnam’s early 20th century: a Bayesian networks analysis of Franco-Chinese house designs

The study of cultural evolution has taken on an increasingly interdisciplinary and diverse approach in explicating phenomena of cultural transmission and adoptions. Inspired by this computational movement, this study uses Bayesian networks analysis, combining both the frequentist and the Hamiltonian Markov chain Monte Carlo (MCMC) approach, to investigate the highly representative elements in the cultural evolution of a Vietnamese city’s architecture in the early 20th century. With a focus on the façade design of 68 old houses in Hanoi’s Old Quarter (based on 78 data lines extracted from 248 photos), the study argues that it is plausible to look at the aesthetics, architecture, and designs of the house façade to find traces of cultural evolution in Vietnam, which went through more than six decades of French colonization and centuries of sociocultural influence from China. The in-depth technical analysis, though refuting the presumed model on the probabilistic dependency among the variables, yields several results, the most notable of which is the strong influence of Buddhism over the decorations of the house façade. Particularly, in the top 5 networks with the best Bayesian Information Criterion (BIC) scores and p\u3c0.05, the variable for decorations (DC) always has a direct probabilistic dependency on the variable B for Buddhism. The paper then checks the robustness of these models using Hamiltonian MCMC method and find the posterior distributions of the models’ coefficients all satisfy the technical requirement. Finally, this study suggests integrating Bayesian statistics in the social sciences in general and for the study of cultural evolution and architectural transformation in particular

Interregional Input-Output Analysis between the Mekong Delta Region (MDR) and the Rest of Vietnam (ROV)

The Mekong Delta is an important economic area, located in the southern part of Vietnam. The Mekong Delta has many potential and opportunities for development, but also new challenges in the context of global climate change, sea level rise, as well as the consequences of blocking the river and the Mekong countries also need to increase competition in international integration. In addition to these challenges, the region also has new opportunities when implementing economic restructuring in line with the policy of restructuring the economy in new conditions, including the establishment of special economic zones as PhuQuoc Resort. Besides analysis based on modern economic theory, this paper uses the input-output framework (I/O Inter-sect oral Scope Model) updated in 2016 for two areas: by the Mekong River and the Rest of Vietnam (ROV) to find inter-regional impacts and to calculate some impact assessments of climate change. The study also analyzes some other factors related to the viewpoint of sustainable regional development in new conditions, income distribution and social security

Comparison of velocity distribution in turbulent diffusion jet given by the integral model and code CFD FLUENT 6.0

Integral model is simple in utilization, low in CPU time calculation, suitable for a lot of practical applications of turbulent diffusion jet. However the assessment of accuracy of the model should be carried out by experimental data and by results of available multidirectional codes. The present paper shows the comparison of velocity profiles given by the integral model and the CFD FLUENT 6.0 Code. The difference in results given by the two models is lower than 10% when Reynolds number at the exit nozzle below 5000

Examination of influential factors on shear strength of externally bonded FRP reinforcement in RC beams

The fiber-reinforced polymer (FRP) retrofitting technique has been increasingly created to enhance the capacity of the existing concrete members. In this study, the shear contribution of the external FRP strengthening system in the reinforced concrete (RC) beams is estimated by the semi-empirical models available in the open literatures and guidelines. Number of beams monitored in the previous studies are first considered to assess the reliability of the models. Afterwards, the investigation of influential factors such as the beam configurations, the strengthening characteristics and the material properties are implemented. With high accuracy and low coefficient of variation, the model proposed in a previous study of the authors gains the mostly considerable estimation for the shear resisting strength of FRP strengthening system compared to the accessible data base from the experiments. In addition, the critical properties of the materials associating with the retrofitting systems for the strengthened beams are investigated to obtain the acquired shear performance