65 research outputs found
Mineral Resources Potential of Vietnam and Current State of Mining Activity
Vietnam, with an area of 331,210 km2, occupies the eastern side of the Indochina peninsula. It forms a narrow (locally only 40-70 km) band of land, extending over 1,500 km along the East Sea (South China Sea). Vietnam is constituted mainly by the folded belts surrounding two shields, cratonised in the Upper Proterozoic: the Yangtze craton and the Indochina shield, located in the Mekong basin and occupying most of Cambodia and the contiguous parts of Laos and Vietnam. The folding occurred during the late Hercynian (early Triassic) orogenic movements, active mainly in the central and southern Vietnam and the Indosinian (late Triassic, ante Norian) orogeny. Various geological surveys have indicated that Vietnam is well endowed with a wide range of mineral resources. The country has some of the world's biggest resources of phosphate (apatite), bauxites, rare earths, and large, commercially viable deposits of oil, coal, gold, gemstones, copper, zinc, tin, chromite, manganese, titanium (mineral sands), graphite and other minerals. At present, Vietnam produces approximately 3.5 million tons of crude oil/year and its mineral production includes: coal (about 10.7 million tons a-1), cement (1.6 million tons), phosphate (300,000 tons), chromite (3.5 million tons), iron ores, gold (around 1,000 kg, including production by the local population), cassiterite (3,000 tons), graphite, kaolin and many other minerals produced to serve domestic demand. Several foreign companies are involved in oil exploration (BP, Total, BHP) as well as in prospecting (seldom in exploitation) for minerals (mainly Australian companies). In spite of the current mineral production, the country’s mining sector is still under-developed and many available mineral resources remain unexploited. Nevertheless, this situation is changing. The recent but increasing level of involvement of foreign companies in the Vietnamese mineral sector will accelerate the development of high value and/or export-orientated minerals, especially as some of the neighboring countries (China, Japan, South Korea ...) lack many mineral resources. And the developing Vietnamese economy will surely entail mining of various minerals for the domestic use
The impact of recentralization reform on corruption: evidence from a quasi-natural experiment
How does government recentralization reform affect corruption? We utilize the pilot recentralization reform that transforms the legislative function, power, and responsibility of the district-level authorities to the higher level of the government organ in Vietnam as a quasi-natural experiment to address the aforementioned question. We find strong evidence that recentralization reform leads to lower corruption. The result illustrates that, among the firms which have the highest probability of making a bribe payment, those incorporated in jurisdictions experiencing the recentralization reform are 4.3% less likely to pay a bribe. In addition, the perception that bribery is a common and necessary practice is also significantly lowered in the post-recentralization period. We further show that the impact of recentralization is stronger for firms which lack a political connection. Overall, these results shed light on the real impact of the government recentralization reform and also the determinants of corruption, thereby providing important policy implications for policymakers to create a more conducive business environment
Robust Adaptive Cerebellar Model Articulation Controller for 1-DOF Nonlaminated Active Magnetic Bearings
This paper presents a robust adaptive cerebellar model articulation controller (RACMAC) for 1-DOF nonlaminated active magnetic bearings (AMBs) to achieve desired positions for the rotor using a robust sliding mode control based. The dynamic model of 1-DOF nonlaminated AMB is introduced in fractional order equations. However, it is challenging to design a controller based on the model\u27s parameters due to undefined components and external disturbances such as eddy current losses in the actuator, external disturbance, variant parameters of the model while operating. In order to tackle the problem, RACMAC, which has a cerebellar model to estimate nonlinear disturbances, is investigated to resolve this problem. Based on this estimation, a robust adaptive controller that approximates the ideal and compensation controllers is calculated. The online parameters of the neural network are adjusted using Lyapunov\u27s stability theory to ensure the stability of system. Simulation results are presented to demonstrate the effectiveness of the proposed controller.The simulation results indicate that the CMAC multiple nonlinear multiple estimators are close to the actual nonlinear disturbance value, and the effectiveness of the proposed RACMAC method compared with the FOPID and SMC controllers has been studied previously
Multivalvular involvement associated with Libman-Sacks endocarditis detected by multimodality imaging: A case report
Libman-Sacks endocarditis accounts for 6–11 percent of systemic lupus erythematosus patients and is associated with varying degrees of valvular dysfunction, increased risk for stroke and transient ischemic attacks, and increased mortality. In previous studies, left-sided valvular Libman-Sacks vegetations were more frequently detected than right sided vegetations; reported cases of bilateral involvement is very rare. A comprehensive clinical assessment and the multimodality imaging is of utmost importance in the management of systemic lupus erythematosus. In this case report, we describe a 31-year-old female patient with uncontrolled systemic lupus erythematosus initially presented with gastrointestinal symptoms but eventually had a vegetation-like structure on the posterior leaflet of the mitral valve which was revealed during routine echocardiography. Two-dimensional/three-dimensional transthoracic and transesophageal echocardiography, cardiac magnetic resonance, and cardiac computed tomography further characterized the mitral valve vegetation and revealed an additional vegetation of the pulmonary valve. Echocardiography remains the cornerstone for the detection of Libman-Sacks vegetations. Cardiac MRI and cardiac CT are useful in characterizing lesion size and effects and may prove particularly helpful in the assessment of right-sided or multivalvular endocarditis. The presence of focal brain lesions on brain MRI prompted antithrombotic therapy
SIP-MBA: A secure IoT platform with brokerless and micro-service architecture
The Internet of Things is one of the most interesting technology trends today. Devices in the IoT network are often geared towards mobility and compact in size, thus having a rather weak hardware configuration. There are many light weight protocols, tailor-made suitable for limited processing power and low energy consumption, of which MQTT is the typical one. The current MQTT protocol supports three types of quality-of-service (QoS) and the user has to trade-off the security of the packet transmission by transmission rate, bandwidth and energy consumption. The MQTT protocol, however, does not support packet storage mechanisms which means that when the receiver is interrupted, the packet cannot be retrieved. In this paper, we present a broker-less SIP-MBA Platform, designed for micro-service and using gRPC protocol to transmit and receive messages. This design optimizes the transmission rate, power consumption and transmission bandwidth, while still meeting reliability when communicating. Besides, we implement users and things management mechanisms with the aim of improving security issues. Finally, we present the test results by implementing a collect data service via gRPC protocol and comparing it with streaming data by using the MQTT protocol.Web of Science12759358
IoHT-MBA: An Internet of Healthcare Things (IoHT) platform based on microservice and brokerless architecture
Internet of Thing (IoT), currently, is one of the technology trends that are most interested. IoT can be divided into five main areas including: Health-care, Environmental, Smart city, Commercial and Industrial. The IoHT-MBA Platform is considered the backbone of every IoT architecture, so the optimal design of the IoHT-MBA Platform is essential issue, which should be carefully considered in the different aspects. Although, IoT is applied in multiple domains, however, there are still three main features that are challenge to improve: i) data collection, ii) users, devices management, and iii) remote device control. Today's medical IoT systems, often too focused on the big data or access control aspects of participants, but not focused on collecting data accurately, quickly, and efficiently; power redundancy and system expansion. This is very important for the medical sector - which always prioritizes the availability of data for therapeutic purposes over other aspects. In this paper, we introduce the IoHT Platform for Healthcare environment which is designed by microservice and brokerless architecture, focusing strongly on the three aforementioned characteristics. In addition, our IoHT Platform considers the five other issues including (1) the limited processing capacity of the devices, (2) energy saving for the device, (3) speed and accurate of the data collection, (4) security mechanisms and (5) scalability of the system. Also, in order for the IoHT Platform to be suitable for the field of health monitoring, we also add realtime alerts for the medical team. In the evaluation section, moreover, we describe the evaluation to prove the effectiveness of the proposed IoHT Platform (i.e. the proof-of-concept) in the performance, non-error, and non affected by geographical distance. Finally, a complete code solution is publicized on the authors' GitHub repository to engage further reproducibility and improvement.Web of Science12760159
Changes in the Recovery Efficiency, Nutritional and Safety Quality of Dried Sergestid Shrimp (Acetes species) during Commercial Production
The sun-dried method is popular for producing dried Sergestid shrimp in Vietnam, but maintaining consistent product quality across seasons is challenging due to its dependence on weather conditions. A previous study used convection drying at a laboratory scale. In this study, the laboratory scale was upgraded to a commercial scale, and recovery efficiency and Sergestid shrimp images were recorded during production stages. Parameters were adjusted for economic efficiency and convenience. Results showed a decrease in recovery efficiency on the laboratory scale, while the commercial scale improved with washing and blanching. Overall, there was no significant difference in recovery efficiency between the commercial production (15.76 %) and laboratory scale (16.29 %). The commercial-scale dried Sergestid shrimp exhibited better colour than the laboratory-scale product. The product met food safety and quality criteria according to Vietnamese standards. Microorganisms such as Coliforms, E. coli, B. cereus, C. perfringens and salmonella, and total number of yeast and mold spores, were not detected in the product. On the other hand, the product of commercial production contained 256 kcal 100 g−1 of energy and a protein content of 55.50 ± 0.33 %. These findings form a foundation for scaling up production and assessing economic feasibility. Adjusting production parameters using larger equipment contributes to achieving optimal production efficiency and economic benefits
Heat Dissipation for Microprocessor Using Multiwalled Carbon Nanotubes Based Liquid
Carbon nanotubes (CNTs) are one of the most valuable materials with high thermal conductivity (2000 W/m·K compared with thermal conductivity of Ag 419 W/m·K). This suggested an approach in applying the CNTs in thermal dissipation system for high power electronic devices, such as computer processor and high brightness light emitting diode (HB-LED). In this work, multiwalled carbon nanotubes (MWCNTs) based liquid was made by COOH functionalized MWCNTs dispersed in distilled water with concentration in the range between 0.2 and 1.2 gram/liter. MWCNT based liquid was used in liquid cooling system to enhance thermal dissipation for computer processor. By using distilled water in liquid cooling system, CPU’s temperature decreases by about 10°C compared with using fan cooling system. By using MWCNT liquid with concentration of 1 gram/liter MWCNTs, the CPU’s temperature decreases by 7°C compared with using distilled water in cooling system. Theoretically, we also showed that the presence of MWCNTs reduced thermal resistance and increased the thermal conductivity of liquid cooling system. The results have confirmed the advantages of the MWCNTs for thermal dissipation systems for the μ-processor and other high power electronic devices
Application of Fuzzy-ANFIS Controller for Ball on Wheel System
The ball-on-wheel (BoW) is a nonlinear single input-multi output (SIMO) system consisting of a ball located on a wheel. The system’s challenge is to balance ball at the highest point on the wheel. In this paper, we propose a method of applying ANFIS toolbox in imitating a successful controller (in this case, it is PD controller). This process creates a similar fuzzy controller which controls well this system. Therefore, through this research, ANFIS toolbox shows the ability in imitating an expert‘s control law through collecting data of operations
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