Journal of Water resources & Environmental engineering

Study of irrigation water pricing method based on service approach

2023-04-25T04:46:37+07:00

Irrigation service pricing has been receiving much attention from state management agencies and researchers, especially in the context of implementing the Law on Hydraulic Works. Although irrigation water pricing method has been regulated by the State, its implementation and efficiency for different types of irrigation systems are themes of discussion. This paper presents method for determining irrigation water prices based on a service approach and uses two-component water pricing to calculate irrigation water prices for the study case of pump irrigation system of Thanh Nghia cooperative. The research results indicated that irrigation service prices depend remarkly on the level of service provided. An adjustment of pump head and selection of pumping time are two key factors affecting the cost of irrigation system, and therefore, the irrigation service prices. The results showed that the variable cost of the irrigaiton system would decrease about 75% in a possible case for choosing by the farmers. The application of service-based approach and twocomponent water pricing is able to change the behavior of supplier and water users towards achieving efficiency in irrigated agricultural production. This study provides lessons learnt for implementation and replication of the new irrigation water pricing method for various irrigation systems nationwide in the future

Design optimization of the condenser of loop heat pipe using a 1-dimensional numerical model

2023-04-25T04:46:50+07:00

This paper reports the optimal calculation of loop heat pipe condensers length based on the maximum length of the condenser, the maximum heater temperature, and the condensation condition. A 1-dimensional numerical model, which assumes heat is transferred through 1 direction, was used for the calculation. A new solution algorithm was proposed using 3 additional conditions of condensers length, the pore diameter of the wick, and temperature limitation of the heat source besides the other 2 conditions of thermal energy balance and capillary/loss pressure. The calculation converged and the results were suitable qualitatively, for example, the condensers length was smaller in case of worsening condensation condition (natural convection) than in case of better condensation condition (forced convection) or to obtain shorter condensers length smaller pore diameter was required. However, experimental researches have to be carried out in the next step to confirm these results quantitatively

The study on calculation methods to determinate basic parameters of photovoltaic pumping sytem (PVPS) supplying water for remote areas

2023-04-25T04:46:58+07:00

The life of ethnic minority communities in remote areas is still difficult. Water and power supply for domestic use is still inadequate, especially the water source for daily use. When the infrastructure has not been invested, grid electricity has not reached these areas, Photovoltaic Pumping System (PVPS) is an effective solution. Currently, in Vietnam, the PVPS system is almost not applied because there is no scientific basis for calculation and design of this system. This paper provides a scientific basis for calculating the capacity as well as the flow rate of the solar pumping system. The study was applied to calculate the PVPS system supplying domestic water for Lung Lu villages in Ha Giang provice.

Method for building universal levels of training: Case studies for majors hydraulic construction technology in Thuyloi university

2023-04-25T04:47:04+07:00

Building economic - technical norms on training as a basis for determining training costs is really necessary, an important basis for implementing the policy of innovation. The full calculation of training costs to implement the mechanism of assigning tasks, ordering or bidding for public service provision with the use of state budget funds. University-level training for majors in the fields of agriculture and rural development in our country shows that most industries have a low level of socialization, especially for training industries. Such as Soil Science, Engineering construction of water works... The job demand for university-educated human resources of the This discipline is huge. The article researches on training norms of hydraulic engineering at the Thuyloi University as a basis for calculation for lecturers.

Research on the sliding mode control algorithm for an automotive active suspension system

2023-04-25T04:47:10+07:00

The suspension system is used to control the vibrations of the vehicle while traveling on the road. In this paper, the sliding mode control (SMC) algorithm is designed to control the active suspension (active suspension). This is a complex algorithm, and it is suitable for nonlinear oscillation systems with the input excitation being of predetermined form, such as automobile suspension systems. The simulation process is done by MATLAB-Simulink software with two specific cases. According to the calculation results, the displacement and acceleration of the vehicle body are reduced sharply when using the sliding control algorithm for the suspension system. In addition, the car's stability is also better guaranteed when equipped with an active suspension system (as evidenced by the change in wheel dynamics load). The chattering phenomenon still occurs when the oscillation changes phase;
this is the nature of the sliding mode control algorithm. However, its influence is not great. In the following studies, the sliding mode control algorithm can be combined with other intelligent algorithms to solve this problem.

Sedimentation transportation model in Soc Trang coastal area by grain size trend analysis method

2023-04-25T04:47:18+07:00

The distribution of sediments in the coastal and estuary region is quite complicated. The sediments in these areas are influenced by many natural factors such as tidal regimes, inshore currents as well as pathways of sediment transport from the rivers. Spatial variation of particle size parameters may reflect sediment transport patterns and sedimentation dynamics environments. In this study, 169 samples of coastal surface sediments in Soc Trang province were collected using a specialized sediment grab and analyzed to evaluate the sediment distribution in this area. These samples were analyzed by the Laser diffraction analysis on Horiba LA-960V2. The proportion of sand and alluvium in the samples is 43.98% and 56.02%, respectively. In the sand composition, small sand accounted for 52% (0.125 - 0.25 nm), very small sand accounted for 48% (0.063 - 0.125 nm), and the average grain grade of the whole sample is 4.61(Φ). The fine-grained components are mainly concentrated along the coast and gradually coarser towards the sea. It shows that the coastal currents dominate and affect the coastal sediments in the study area

Stakeholder engagement in mangrove governance: Case study in the north and north central coastal Vietnam

2023-04-25T04:47:24+07:00

Mangroves are known as an ecosystem with important environmental and economic roles. Implementing good mangrove governance is a necessary condition to ensure the conservation and promotion of these important ecosystem functions and services. Participation is at the core of resource management in general and mangroves in particular. Therefore, the objective of the study is to assess the status of stakeholder participation in mangrove governance. The results show that the group performing the state management function is assessed as having a high influence and this group is also said to be highly interested in the management of mangroves in the localities. The local mangrove development support group is assessed as having a low to high level of interest. The group directly involved in the protection and use of mangroves is said to have a high degree of influence and interest in mangrove management and development in the localities.

Methods for determining the pricing of undergraduate training services in hydraulic structures engineering at Thuyloi university

2023-04-25T04:47:30+07:00

Education and training are the basis for creating a quality labour force, discovering talents, and creating conditions for them to develop their full potential. In order to have a foundation and conditions for implementing regulations on assigning tasks, ordering, or bidding for the provision of undergraduate training services with the use of state budget funds for branches in the fields of agriculture and rural development, the Ministry of Agriculture and Rural Development has implemented the determination of the list of training disciplines, the development of economic and technical norms for undergraduate training, the criteria for selecting the training providers providing training services, etc. To have sufficient grounds for providing training services at the university level, it is necessary to calculate the training service price. The article researches the price of training services in the field of Hydraulic Structures Engineering at Thuyloi University to serve as a basis for future application

Determination of load-bearing capacity of bored piles based on axial static compression test results in field conditions

2023-04-25T04:47:34+07:00

Determining the load-bearing capacity of bored piles from axial static compression tests is a reliable method that allows testing of the calculated load-bearing capacity according to theory, thereby selecting the most accurate load-bearing capacity value for the pile. The principle of the experimental method is to load the pile in axial compression gradually, and measure the corresponding settlement of the pile until the ultimate load value of that load level is reached. This method is suitable for the practical working model of the pile and soil, thus providing highly reliable results in evaluating the load-bearing capacity of the pile. However, quantifying the displacement of the pile head corresponding to the ultimate load, which is only a convention; or the axial compression load, Pthu, is specified to be taken as two hundred percent of the design loadbearing capacity, Ptk, while this value depends on the theoretical calculation method of the pile load-bearing capacity, geotechnical conditions, and depth of the pile, resulting in different errors in the obtained results. This article is based on the results of axial static compression tests on bored piles at some construction sites in weak soil areas in Ho Chi Minh City, comparing and evaluating
them with load-bearing capacity values calculated from different theoretical methods in TCVN 10304: 2014

Solutions to integrated water resources management on Phu Quoc island

2023-04-25T04:47:39+07:00

Phu Quoc is the largest and beautiful island in Vientam. The unique environmental features of this island contribute to tourism appeal. The economic development focusing on tourism and urban expansion has been putting great pressure on water resources in this area. Although surface water is relatively abundant, Phu Quoc is facing many challenges in the development due to the temporal uneven distribution of surface water, along with increasing water demand. These are water scarcity in the dry season, partial flooding in the rainy season and water pollution, especially in the context of climate change. To ensure the sustainable development of Phu Quoc island, the application of integrated water resource management is necessary in this area. On the basis of assessing the existing legal framework and institutional settings for water resource management in Vietnam, as well as analyzing the current problems of water resources, this article has proposed several solutions to intergrated water resources management on Phu Quoc island as required by the existing legal framework.

Technology for controlling the flow fluctuation during operation of sluice in flood season, applied to sluice in Phuc Tho commune

2023-04-25T04:47:45+07:00

The flow fluctuation has been studied in quite extensively for large-scale flood control works, however, this issue has been less addressed for culverts through levee. The operational experience has shown that there are many negative impacts of flow dynamics on the culvert structure and levee system such as the uplift instability, the local surface erosion of the stilling basin or the downstream channel, collapsing of part of the levee system, etc. According to the requirement of sluice and levee safety during flood season, the task of reducing fluctuation needs to be performed. The article not only pointed out the types of fluctuation that need to pay attention behind the operation gate, but also specified the locations where the sluice and levee could be destructively affected by the fluctuation. In addition, structural and non-structural countermeasures reducing negative impacts of fluctuation are also mentioned. Research has proposed measures to reduce flow dynamics for operating culverts without interfering with their structure.

Experimental investigation of heat transfer for a free jet impinging on a flat surface

2023-04-25T04:47:51+07:00

This paper reports the study of heat transfer of a free jet impinging on the heated flat surface. The horizontal free jet of water was impinged on the vertical surface, which was the heated copper metal plate. The images of temperature field on the copper plate were taken with an infrared thermal camera. Thus, the thermal images were used to discuss the heat transfer of the impinging jet.

Policies and institutions in mangrove forest governance in Vietnam

2023-04-25T04:47:54+07:00

Mangroves are important ecosystems that need to be well managed to preserve and promote their values. The research focused on the current status of policies and institutions for mangrove management. The results show that most of the mangrove areas in Vietnam (except special-use forests) are managed by the Commune People's Committee under the direct guidance of the Department of Natural Resurces and Environment (DONRE) at districts and provinces. Forest owner groups: Management Boards, Commune People's Committees cooperate with local communities and social organizations. There is an overlap between forest owner groups as well as management forms. The right to decide on the how to use mangroves, manage the forest area belongs to the goverment (through apropriate authorities). In general, mangrove management policy currently not yet encourage the participation of stakeholders. This result shows that it is necessary to continue to develop institutional and policy systems to better support mangrove governance

Research on optimal operation method of multi- reservoir cascade hydropower using genetic algorithm

2023-04-25T04:47:58+07:00

Optimizing the operation of hydropower plants (HPPs) is of great significance for the Vietnamese power system in the context of an increasing trend of renewable energy sources in power generation. HPPs with regulated reservoirs can be an effective solution to ensure balance and stability for the power system. To optimize the operation of reservoirs for power generation, classical mathematical optimization algorithms such as linear programming, nonlinear programming, and dynamic programming are commonly used. Currently, genetic algorithm (GA) is the most widely applied algorithm in the field of artificial neural networks (ANN) to find optimal weights. Applying the GA algorithm to the optimization of the operation of cascade hydropower reservoirs is a good solution for making operational decisions for the reservoir system. This article provides a basis for applying the GA algorithm to calculate optimal power generation operation for the Lai Chau, Ban Chat, Son La, Hoa Binh cascade hydropower reservoir system.

Reliability of benefits steel strong steel frame resistance to windload using finite element method

2023-04-25T04:48:03+07:00

The article studies the Stochastic Finite Element Method (SFEM) to analyze bevel frames with semi-rigid connections subjected to wind loads when the connection and load parameters are the same quantities. random. Algorithm to analyze the structure's behavior is a combination of the method of mathematical modeling and the Monte-Carlo simulation. The calculation program is then used to evaluate the reliability of a semi-rigid beveled steel frame subjected to wind loads