352 research outputs found

    Extended state observer based load frequency controller for three area interconnected power system

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    In this paper, we develop a new extended state variable observer based LFC scheme for three-area interconnected power systems. The extended state observerbased load frequency controllers are developed which utilize disturbance estimation techniques. The propose control approach assures that the fluctuating things of the load frequencies reaches to a safer range and the load frequencies can also be made at a very minimal not to have an effect on power quality and power flow in multi-area interconnected power system. The results of the simulations using MATLAB/SIMULINK done did not only address that the proposed newly control method works effectively but also change powerfully the parameter variations of the interconnected areas of the power system. Especially, it works very well to limit disturbances impact on interconnected areas in the system. Therefore, the performance of interconnected power system under different multi-conditions is simulated with the new control method to demonstrate the feasibility of the system

    Evaluate the Results at Minimum 2-Years of Treating Rotator Cuff Tear by Arthroscopic Surgery

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    BACKGROUND: Rotator cuff tear (RCT) is a common injury of the shoulder, especially middle-aged people. Nonoperative treatment, cortisone injections are only effective at an early stage. Open surgery causes postoperative atrophy of the deltoid muscle, so results are limited. Arthroscopic rotator cuff repair surgery has been performed in Vietnam for about ten years, with many advantages such as the ability to accurately assess the lesions and less invasive procedure. In order to have a clearer view, we performed a mid-term assessment of the effectiveness of this surgery. AIM: Evaluate results over 2 years of patients with rotator cuff tears treated with arthroscopic surgery and their quality of life. METHOD: A group of 30 patients were diagnosed with RCT and surgery by arthroscopy to treat at Hanoi Medical University Hospital and Saint Paul Hospital between Jun 2015 and April 2017. The results of the surgeries were assessed by the degree of pain, muscle power, motion of the shoulder joint according to UCLA shoulder score. Evaluate the quality of life through the Rotator Cuff-Quality of Life (RC-QoL) index. RESULTS: The average age was 60.7 years. Female / male ratio was 1.3. Thirty-six months ± 6.41 was the average follow-up time (min 27 – max 50 months). The shoulder function is recorded according to UCLA has an average score of 30.9, therein good and excellent result were 90 %. The mean RC-QoL index was 91.5%. CONCLUSION: Treatment of RCT by arthroscopic surgery that has been evaluated for a minimum of 2 years follow-up showed good results and high quality of patient’s life

    Farmers practices in organic and inorganic fertilization on crops, trees and vegetables

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    224pThis chapter provides the analysis and evaluation of compost utilization for agricultural production in Thai Binh province, Vietnam, as well as the database for simulating future possibilities of the usage of pig effluence through provincial orientations for livestock development up to 2010 in Thai Binh province. Requirement of organic fertilizer in agricultural production is major absorption banks of waste from livestock components and human ejection that includes rice-based system and annual crops, fruit trees and aquaculture system. Details of the capacity of absorption of each component which depends on soil characteristics, crops' demand, season cropping and farming management techniques by farmers, are provided. Field survey results clearly indicated that agriculture in Thai Binh has facing with the shortage of organic fertilizer and imbalance nutrient in production

    Síntesis de interpolación de los controladores para un sistema de accionamiento eléctrico multimotor que contiene un elemento enlazado elásticamente

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    Partial differential equations, integral, differential, or other equations describe multi-motor automatic electric drive systems containing elastic conveyor belts. Because of the elastic and distributive nature of the system parameters, the transfer function describing them is often a complex expression, containing not only the arguments as a linear system but also the inertial and transcendental components. This makes the precise control of tension and speed synchronously much more complicated than the centralized parameter system. A promising numerical solution based on the real interpolation method will simplify the procedure for synthesizing control loops while preserving the characteristic properties of objects with distributed parameters. The objective of the study is to propose a feasible solution for synthesizing the regulators based on the real interpolation method; it allows direct operation with the original transfer function containing the inertial and transcendental components. In this paper, we proposed an approach to synthesize the control system for objects with distributed parameters using the real interpolation method to reduce computational capacity and synthesis error while preserving the properties of this object class. Building an experimental model of the two-motor electric drive system containing an elastic conveyor to verify the effectiveness of the proposed algorithm. The simulation and experimental results indicate that the control system with the received regulators operating stably and meets the required quality criteria. It proves the efficiency of the synthesis algorithm based on the real interpolation method.Introducción: los sistemas de accionamiento eléctrico multimotor que incluyen transportadores elásticos son un ejemplo de sistemas típicos con parámetros distribuidos descritos por ecuaciones complejas. Debido a la naturaleza elástica y distributiva de los parámetros del sistema, la función de transferencia que los describe suele ser una expresión compleja que contiene los componentes inercial y trascendental. Problema: la naturaleza elástica y distributiva de los parámetros del sistema hace que el control preciso de la tensión y la velocidad sincrónicamente sea mucho más complicado que el sistema de parámetros centralizados. Metodología: se propone una solución numérica para sintetizar los reguladores basada en el método de interpolación real para reducir la capacidad computacional y el error de síntesis preservando las propiedades características de los objetos con parámetros distribuidos. Conclusión: la eficacia del algoritmo propuesto se verifica mediante un modelo experimental del sistema de accionamiento eléctrico de dos motores que contiene un transportador elástico. Los resultados de simulación y experimentales indican que el sistema de control con los reguladores recibidos opera de manera estable y cumple con los criterios de calidad requeridos. Originalidad: los resultados de la investigación se pueden aplicar en el desarrollo de sistemas centrales de control y monitoreo para líneas de producción automáticas con sistemas de accionamiento multimotor que incluyen transportadores

    THE VIEWS OF SOME ECONOMIC THEORIES ON THE ECONOMIC CRISIS OF CAPITALISM AND SOME LESSONS FOR VIETNAM

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    After a brief analysis of the views presented in the economic theories of neo-liberalism, Keynes and Marx on the economic crisis of capitalism the authors of this article point out some methodological recommendations for the development of socialistic-oriented market economy in Vietnam. The experience of dealing with the crisis shows the importance of upholding the advantages of socialist regime: the leadership of the Communist Party in appropriate policyguidelines, the role of the Government in its consistent implementation of its policies, the role of the state's economic sector in sustaining the stability of the whole economy as well as in economic recovery, the contribution and support by the people for the common cause of development of Vietnam

    Composition of animal manure and co-products

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    224pThis study was conducted to determine the real outflow of liquid effluents to be considered in balance calculations at the farm and regional levels in Vietnamese conditions. The variability of the chemical composition of a local dataset was analysed considering the highly heterogeneous wastes and byproducts used on crops. Near infrared spectroscopy (NIRS) was introduced to evaluate the feasibility of a rapid technique applied to animal wastes. Characterization of effluent outflows and water use and composition variation of solid co-products (compost and fish food) was carried out. Quantity of animal solid waste per pig head in the cold seasons was higher than in the hot season. Data collected from ten farms in Thai Binh (Vietnam), showed that the content of the main constituents in the fresh weight (FW) in the warm season was 17.3% OM total. Nitrogen, P2O5 and K2O totals were 160, 3.51 and 0.59%, respectively. Raising pigs in the cold season discharged 0.352kg N, 0.229 kg P2O5 and 0.148 kg K2O per metric ton live weight and he liquid part contributed 5.5, 2.1 and 12.8%, respectively. A total of 66 samples of compost and animal waste as fish feed were taken during summer, of which 46 were ready-to-spread compost, 20 others were animal excreta as fish feed. These results confirmed the fact that it is possible to use the animal waste source coming from the pig farms of Thai Binh province as a main nutrient for crops, especially for rice. After preliminary calibrations using NIRS spectrometry with local pig waste and co-products, perspectives are promising in terms of research and local development. A description of the design of the Chinese digester, more commonly called biogas digester and of the NIRS technique is provided

    A Murnaghan-Nakayama rule for Grothendieck polynomials of Grassmannian type

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    We consider the Grothendieck polynomials appearing in the K-theory of Grassmannians, which are analogs of Schur polynomials. This paper aims to establish a version of the Murnaghan-Nakayama rule for Grothendieck polynomials of the Grassmannian type. This rule allows us to express the product of a Grothendieck polynomial with a power sum symmetric polynomial into a linear combination of other Grothendieck polynomials.Comment: 10 pages, 7 figure

    Research on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy when modified by La, Ce and thermo-mechanical treatment

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    Influence of rare-earth (La, Ce) and thermo-mechanical treatment on microstructure and mechanical properties of Al-Zn-Mg-Cu alloy are presented in this article. After casting, the alloy which was modified by La, Ce, the grain size of samples obtained around 40–50 Âµm compared to that of without about 65 Âµm; and after homogeneous, the grain sizes is about 30 Âµm. After the cold deformation process, the distance between plates is 10 Âµm. By EDS after casting, the samples have tended to more La, Ce elements at the grain boundary, after homogeneous, the uniformation distribution of rare-earths was presented by mapping of EDS’s results. In addition, after rolling and heat treatment, the elements were found on the grain boundary and matrix. After recrystallization annealing, the grain size is around 10 Âµm with the modification sample. The grain size was reduced by two processes of modification as well as thermal-mechanical treatment is a condition for increasing the ductility of the studied alloy. Further, as a result of ability deformation from the tensile test, these results demonstrate that the tensile test obtained 140 % when adding La, Ce contents into the alloy combine with thermal-mechanical treatment. The combined used of La, Ce and thermal-mechanical treatment have increased the ductility of Al-Zn-Mg-Cu allo

    Slender piezoelectric cantilevers of high quality AlN layers sputtered on Ti thin film for MEMS actuators

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    Very good crystallinity and highly c-axis-oriented aluminum nitride (AlN) thin films are sputtered on titanium (Ti) to fabricate thin piezoelectric cantilevers. Raman spectroscopy measurements and X-ray diffraction (XRD) indicate the high quality of these AlN films. A fabrication process, fully CMOS compatible, is developed to realize slender piezoelectric microcantilevers. Actuation enhancement for the AlN piezoelectric cantilevers is achieved by coating the slender beams with a thin PECVD silicon nitride (SiN) layer. Very good linearity and high displacement, up to 19.5 nm for 200 ÎĽm long cantilevers and 4.25 nm for 100 ÎĽm long cantilevers for 1 V actuation at quasi-static mode, are obtained with a 500 nm SiN top layer. These displacement values are three times larger than our previously reported values for cantilevers without SiN layer coating. This makes these cantilevers, without the need of employing nonstandard metals such as platinum (Pt), very promising for micro/nanoactuators
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