131 research outputs found

    Assessment of Radioactive Gaseous Effluent Released from Ninh Thuan 1 Nuclear Power Plant under Scenario of INES-level 7 Nuclear Accident

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    Based on guidance RG 1.109, RG 1.111 published by United States Nuclear Regulatory Commission (USNRC) our research concentrates on assessing radiation doses caused by radioactive substances released from the Ninh Thuan 1 nuclear power plant (NPP) to the environment under scenario of an INES-level 7 nuclear accident caused by two incidents: Station Black Out (SBO) and Loss of Coolant Accident (LOCA) using software RASCAL4.3 provided by the Emergency Operations Center of USNRC. The NPP Ninh Thuan 1 is assumed to use the VVER-1200 technology with a total power of 2400 MWe from two units. The input data for the model calculations is built based on the accident scenario, the technical parameters of VVER-1200 technology and the meteorology. In this work the meteorological data on dry and rainy seasons which are typical for the Ninh Thuan region was considered. The maximum dose distributions were calculated within 40 km from the NPP site. The distributions are strongly affected by meteorological conditions. In the rainy season the dose values near the plant are higher than those in the dry season due to deposition effect of the radioactive substances. The calculation results show that consequences of the accident are very serious. A total radioactivity of radiological equivalence 225,000 TBq to 131I released to the atmosphere. Within 20km the Total Effective Dose Equivalence (TEDE) values are very high, about several tens of times greater than the dose limit. It is requested to establish National Steering Board for Accident Response to direct the relevant authorities in response for the accident consequences and ensure for security in the area of NPP. The public communication, emergency preparedness plan, people evacuation must be implemented under the guidance of Circular 25/2014/TT-BKHC

    A Knowledge-Based Model For Context-Aware Smart Service Systems

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    The advancement of the Internet of Things, big data, and mobile computing leads to the need for smart services that enable the context awareness and the adaptability to their changing contexts. Today, designing a smart service system is a complex task due to the lack of an adequate model support in awareness and pervasive environment. In this paper, we present the concept of a context-aware smart service system and propose a knowledge model for context-aware smart service systems. The proposed model organizes the domain and context-aware knowledge into knowledge components based on the three levels of services: Services, Service system, and Network of service systems. The knowledge model for context-aware smart service systems integrates all the information and knowledge related to smart services, knowledge components, and context awareness that can play a key role for any framework, infrastructure, or applications deploying smart services. In order to demonstrate the approach, two case studies about chatbot as context-aware smart services for customer support are presented

    Contract Farming as a Determinant of Promoting Tea Marketing Channel for Small Producers in Phu Tho Province

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    Making contracts between farmers and firms (contract farming, for short) plays an important role in establishing access to the agricultural markets for the small producers, especially in the developing and less developed countries. It is argued that contract farming provides farmers with the assured sale of their crops and agro-business firms with a steady supply of agricultural products required by the market. This paper focuses on analyzing benefits of tea producers through signing contract with firms. By using relevant research methods of verifying studying areas, making Participatory Rural Appraisal (PRA), and surveying farmers, the paper finds that although contract farmers receive lower fresh tea price in compared with the price received by non-contract farmers, they would have higher price stability and are provided with market guarantee mechanism. These benefits are really important in context of globalization and market liberalization with the demand for high quality and high value products. It is highly recommended that small farmers therefore should participate in the coordination model between farmers and firms in the process of tea production and marketing in Phu Tho Province, Vietnam.Peer reviewe

    Two Spot Coupled Ring Resonators

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    Abstract. We consider a model of two coupled ring waveguides with constant linear gain and nonlinear absorption with space-dependent coupling. This system can be implemented in various physical situations as optical waveguides, atomic Bose-Einstein condensates, polarization condensates, etc. It is described by two coupled nonlinear Schrödinger equation. For numerical simulations, we take local two-gaussian coupling.It is found in our previous papers that, depending on the values of involved parameters, we can obtain several interesting nonlinear phenomena, which include spontaneous symmetry breaking, modulational instability leading to generation of stable circular flows with various vorticities, stable inhomogeneous states with interesting structure of currents flowing between rings, as well as dynamical regimes having signatures of chaotic behavior. This research will be associated with experimental investigation planned in Freie Universität Berlin, in the group of prof. Michael Giersig

    An Overview of Sustainable Ocean Resources for Socio-economic Development in Vietnam

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    Vietnam is one of the nation with long coastal with many valuable resources, which is the basis for the economy development from the ocean-based activities. This paper outlined the main maritime resources and their contribution to the socio-economic development in Vietnam. The raw data was collected from the readable sources such as General Statistics Office of Vietnam, Vietnam meteorological and meteorological data center…. as well as from the practical investigation. This raw data was processed and analyzed in order to have a general view on the majority marine resources in Vietnam. The results showed that there were 5 main resources (oil, fisheries, natural hydrate, green energy, and tourism) from the ocean, which significantly contribute to the economy development of Vietnam. The highest contribution of the oil value to the GDP was witnessed in 2011 with 26.6% of the GDP. While the value of the fisheries and tourism increased every year, the natural hydrate and energy from the ocean are still young areas, however, they come one step closer to the exploitation, which can greatly contribute to the Vietnam economy growth. With these valuable resources from the sea, Vietnam need to have reasonable policies and strategies for the management, exploitation, and export in order to able to effectively use of these resources for the sustainable economy development. Keywords: Ocean resources, sustainable development, fisheries, crude oil exploitation DOI: 10.7176/JRDM/69-05 Publication date:September 30th 202

    Simple thermal-electrical model of photovoltaic panels with cooler-integrated sun tracker

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    This paper presents a simple thermal-electrical model of a photovoltaic panel with a cooler-integrated sun tracker. Based on the model and obtained weather data, we analyzed the improved overall efficiency in a year as well as the performance in each typical weather case for photovoltaic panels with fixed-tilt systems with a tilt angle equal to latitude, fixed-tilt systems with cooler, a single-axis sun tracker, and a cooler-integrated single-axis sun tracker. The results show that on a sunny summer day with few clouds, the performance of the photovoltaic panels with the proposed system improved and reached 32.76% compared with the fixed-tilt systems. On a sunny day with clouds in the wet, rainy season, because of the low air temperature and the high wind speed, the photovoltaic panel temperature was lower than the cooler’s initial set temperature; the performance of the photovoltaic panel with the proposed system improved by 12.55% compared with the fixed-tilt system. Simulation results show that, over one year, the overall efficiency of the proposed system markedly improved by 16.35, 13.03, and 3.68% compared with the photovoltaic panel with the fixed-tilt system, the cooler, and the single-axis sun tracker, respectively. The simulation results can serve as a premise for future experimental models

    PRESENT STATE OF OCEAN OBSERVATIONS AND SERVICE IN VIETNAM

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    This paper presents the basic information on the present status of ocean observation and service in Vietnam with focus on the physical oceanography area. Study results show that in recent years, ocean observations of Vietnam have been equipped with a series of modern measured and analyzed instruments, especially at related offices of the Vietnam Academy of Science and Technology (VAST) and Ministry of Natural Resources and Environment (MONRE). The remarkable progress was to carry out the UAV (Unmanned Aerial Vehicle) program to observe oceanographic conditions in nearshore region by VAST from 2013. Earlier, from 2009 the MONRE carried out the program to establish a network of stations to observe waves and current characteristics in nearshore region by high frequency radar technology. However, the current status of ocean observations and services in Vietnam still has shortcomings in both manpower and equipment and the observations are mostly focused in the nearshore region. Services on oceanographic data are still less professional and public. For sustainable development of ocean observations and service, it is necessary to promote international cooperation projects on oceanography especially in the frame-work of IOC/WESTPAC cooperation

    Context-aware Knowledge-based Systems: A Literature Review

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    Context awareness systems, a subcategory of intelligent systems, are concerned with suggesting relevant products/services to users' situations as smart services. One key element for improving smart services’ quality is to organize and manipulate contextual data in an appropriate manner to facilitate knowledge generation from these data. In this light, a knowledge-based approach, can be used as a key component in context-aware systems. Context awareness and knowledge-based systems, in fact, have been gaining prominence in their respective domains for decades. However, few studies have focused on how to reconcile the two fields to maximize the benefits of each field. For this reason, the objective of this paper is to present a literature review of how context-aware systems, with a focus on the knowledge-based approach, have recently been conceptualized to promote further research in this area. In the end, the implications and current challenges of the study will be discussed

    An Updated Loop-Mediated Isothermal Amplification Method for Rapid Diagnosis of H5N1 Avian Influenza Viruses

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    We designed a new set of primers for reverse transcriptase loop-mediated isothermal amplification (RTLAMP) to specifically amplify the HA gene of avian influenza viruses subtype H5N1. By testing nine H5N1 virus strains and 41 clinical samples collected in Northern Vietnam, we found that the new primers showed higher sensitivity and specificity than the previously published RT-LAMP primers and were comparable to the RT-PCR method currently recommended by WHO. These results suggest that our RT-LAMP assay may be a better choice as a diagnostic tool for current H5N1 influenza virus infection

    Gravity terrain correction for mainland territory of Vietnam

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    Terrain corrections for gravity data are a critical concern in rugged topography, because the magnitude of the corrections may be largely relative to the anomalies of interest. That is also important to determine the inner and outer radii beyond which the terrain effect can be neglected. Classical methods such as Lucaptrenco, Beriozkin and Prisivanco are indeed too slow with radius correction and are not extended while methods based on the Nagy’s and Kane’s are usually too approximate for the required accuracy. In order to achieve 0.1 mGal accuracy in terrain correction for mainland territory of Vietnam and reduce the computing time, the best inner and outer radii for terrain correction computation are 2 km and 70 km respectively. The results show that in nearly a half of the Vietnam territory, the terrain correction values ≥ 10 mGal, the corrections are smaller in the plain areas (less than 2 mGal) and higher in the mountainous region, in particular the correction reaches approximately 21 mGal in some locations of northern mountainous region. The complete Bouguer gravity map of mainland territory of Vietnam is reproduced based on the full terrain correction introduced in this paper
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