59 research outputs found

    The maximum power point tracking based-control system for small-scale wind turbine using fuzzy logic

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    This paper presents the research on small-scale wind turbine systems based on the Maximum Power Point Tracking (MPPT) algorithm. Then propose a new structure of a small-scale wind turbine system to simplify the structure of the system, making the system highly practical. This paper also presented an MPPT-Fuzzy controller design and proposed a control system using the wind speed sensor for small-scale wind turbines. Systems are simulated using Matlab/Simulink software to evaluate the feasibility of the proposed controller. As a result, the system with the MPPT-Fuzzy controller has much better quality than the traditional control system

    ANTIBACTERIAL AND PHOTOCATALYTIC ABILITY OF THE Ag/TiO2 COATING ON THE GLASS SURFACE.

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    The coating on the glass surface was made by heating the mixture of resinate Ag and tetra-n-butyl orthotitanate (TBO) at 570 oC for 1 hour. The characteristics and structure of the mixture Ag/TiO2 with the content of Ag : TiO2 from 0 – 8 (% mol) were studied by the methods such as XRD, FTIR, UV-viz, SEM, EDS. The research results of antibacterial ability and the degradation of blue methylene (MB) were shown that this coating can be used for antibacterial and photocatalytic abilit

    Optical Sensors for Planetary Radiant Energy (OSPREy): Calibration and Validation of Current and Next-Generation NASA Missions

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    A principal objective of the Optical Sensors for Planetary Radiance Energy (OSPREy) activity is to establish an above-water radiometer system as a lower-cost alternative to existing in-water systems for the collection of ground-truth observations. The goal is to be able to make high-quality measurements satisfying the accuracy requirements for the vicarious calibration and algorithm validation of next-generation satellites that make ocean color and atmospheric measurements. This means the measurements will have a documented uncertainty satisfying the established performance metrics for producing climate-quality data records. The OSPREy approach is based on enhancing commercial-off-the-shelf fixed-wavelength and hyperspectral sensors to create hybridspectral instruments with an improved accuracy and spectral resolution, as well as a dynamic range permitting sea, Sun, sky, and Moon observations. Greater spectral diversity in the ultraviolet (UV) will be exploited to separate the living and nonliving components of marine ecosystems; UV bands will also be used to flag and improve atmospheric correction algorithms in the presence of absorbing aerosols. The short-wave infrared (SWIR) is expected to improve atmospheric correction, because the ocean is radiometrically blacker at these wavelengths. This report describes the development of the sensors, including unique capabilities like three-axis polarimetry; the documented uncertainty will be presented in a subsequent report

    Optimal design parameters of air suspension systems for semi-trailer truck. Part 2: results and discussion

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    Based on the results of model and algorithm in Part1 for searching the optimal design parameters of vehicle suspensions using genetic algorithm, in Part 2, the simulation results with MATLAB Simulink combined with an optimal program are written to search the optimal design parameters of vehicle air suspension systems in two optimal conditions. The optimal results indicate that the DLC values at all axles of vehicle respectively reduce by 9.09 %, 10.71 %, 11.11%, 10.81 %, 8.82 % (in Case 1) and 14.29 %, 19.23 %, 20.00 %, 17.14 %, 12.12 % (in Case 2) in comparison with the original air suspension systems when vehicle moves on the ISO class C road surface at v= 20 m/s and full load. All these things indicate that using the genetic algorithm optimization method does not only reduce the tire dynamic loads acting on road surface but also improves the ride comfort. Finally, the optimum performance of vehicle suspension systems is considered and reassessed under different operating conditions. The evaluation results indicate that the optimum performance of the air suspension systems has better potential to improve the road friendliness which provides a ride comfort for road surfaces and vehicle

    Optimal design parameters of air suspension systems for semi-trailer truck. Part 1: modeling and algorithm

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    The purpose of this paper is to improve the performance of air suspension systems for a semi-trailer truck in the direction of reducing the dynamic wheel load acting on road surface (Part 1: modeling and algorithm). To achieve the goal of finding the optimal design parameters for the air suspension systems, a half-vehicle dynamic model under the road-vehicle interaction with 12 degrees of freedom (d.o.f) is established for searching the optimal design parameters of vehicle suspensions using genetic algorithm (GA). Dynamic load coefficient (DLC) is considered as a target function. Two optimal conditions: optimal design of geometrical parameters of air spring suspension systems (Case 1) and optimal design of parameters of air suspension systems (Case 2) are selected in this study. The results of this paper are the basis for optimization and discussion in Part 2 as the results and discussion

    KẾT QUẢ BƯỚC ĐẦU NGHIÊN CỨU KHU HỆ CÁ CỬA SÔNG THU BỒN, TỈNH QUANG NAM

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    This report presents the result of four surveys in 2013 at 12 sampling stations on fish composition of fish fauna in the Thu Bon estuary of Quang Nam province (the central Vietnam) and a total of 139 species of fishes were identified belonging to 110 genera, 63 families and 17 orders. Analysis of community structure of fish fauna showed that the order Perciformes was the most popular, making up 56.1%; Cypriniformes (8.6%); Pleuronectiformes (6.5%); Clupeiformes and Siluriformes (4.3%); Anguilliformes, Tetraodontiformes (3.6%); Mugiliformes (2.9%); ... The family Gobiidae was the most abundant with 12 species, making up 8.6% of the total number of species; Cyprinidae (10 species, 7.2%); Leiognathidae, Carangidae had the same number of species (6 species, 4.3%); Clupeidae, Lutjanidae: 5 species (3.6%); Serranidae, Mugilidae, Soleidae, Gerreidae, Ambassidae, Tetraodontidae: 4 species (2.9%); In addition, 4 families had 3 species, 12 families had 2 species and 35 families had 1 species. Cluster analysis based on the Bray - Curtis similarity index of nine fish faunas (Bach Dang, Thai Binh, Bu Lu, Son Tra peninsula, Thu Bon, coastal wetlands of Quang Nam, Nha Phu - Binh Cang, Ben Tre and Tra Vinh) showed that fish composition of the coastal - estuaries of Tra Vinh and Ben Tre had the highest similarity (78%), subsequently fish faunas of Thu Bon had similarity with that of Quang Nam (47%), Quang Nam and Nha Phu - Binh Cang (41%), Bu Lu and Thu Bon (38%). The result was also classified into three distinct groups of 9 fish faunas: group 1- Tra Vinh, Ben Tre and Thai Binh; group 2- Quang Nam, Thu Bon, Nha Phu - Binh Cang, Son Tra and Bu Lu; group 3- Bach Đang. The species richness (Margalef’s index) of Thu Bon (28.0) was less abundant than that of other areas: the highest species richness belonging to Tra Vinh (39.4), Thai Binh (38.6), Nha Phu - Binh Cang (35.9), Son Tra (31.8), Bu Lu (29.7), … The diversity of species composition according to the taxa in each region showed the characteristic of each fish fauna. The fish fauna is evidently typical of characteristics of the estuarine waters and coastal lagoons. There are 4 threatened species which are listed in the Vietnam’s Red Data Book (2007) at ex-tremely vulnerable levels.Thực hiện 4 chuyến khảo sát thu mẫu thành phần loài cá vùng cửa sông Thu Bồn trong năm 2013 tại 12 điểm thu mẫu. Kết quả đã ghi nhận được 139 loài thuộc 17 bộ, 63 họ và 110 giống. Phân tích cấu trúc quần xã khu hệ cá cho thấy: bộ cá Vược Perciformes là bộ cá phổ biến nhất chiếm 56,1%; tiếp đến là bộ cá Chép 8,6%; bộ cá Bơn Pleuronectiformes chiếm 6,5%; bộ cá Trích Clupeiformes và cá Nheo Siluriformes mỗi bộ 4,3%; bộ cá Chình Anguilliformes, cá Nóc Tetraodontiformes (3,6%); bộ cá Đối Mugiliformes (2,9%); ... Các họ chiếm ưu thế về loài: họ cá Bống trắng (Gobiidae) 12 loài chiếm 8,6% tổng số loài; cá Chép (Cyprinidae) 7,2%; cá Liệt (Leiognathidae) và cá Khế (Carangidae) mỗi họ 4,3%; cá Trích (Clupeidae), cá Hồng (Lutjanidae): 3,6%, ... So sánh với 8 khu hệ cá cửa sông - ven biển Việt Nam (Bạch Đằng, Thái Bình, Bù Lu, Sơn Trà, vùng đất ngập nước ven biển tỉnh Quảng Nam, Nha Phu - Bình Cang, Bến Tre và Trà Vinh) ghi nhận, vùng ven biển cửa sông Trà Vinh và Bến Tre có mức tương đồng cao nhất 78%, tiếp đến là Quảng Nam và Thu Bồn 47%, Quảng Nam và Nha Phu - Bình Cang 41%, Bu Lu và Thu Bồn 38%. Phân tích chỉ số giống nhau về thành phần loài của 9 khu hệ cá hình thành nên 3 nhóm: nhóm 1: Trà Vinh, Bến Tre và Thái Bình; nhóm 2: Quảng Nam, Thu Bồn, Nha Phu - Bình Cang, Sơn Trà và Bù Lu; Bạch Đằng hình thành riêng nhóm 3. Độ giàu có về loài của Thu Bồn đạt 28,0; Trà Vinh đạt cao nhất 39,4; tiếp đến là Thái Bình (38,6); Nha Phu - Bình Cang (35,9), Sơn Trà (31,8), Bù Lu (29,7), … Tính đa đạng về thành phần loài cá theo các bậc taxon trên từng vùng thể hiện tính đặc trưng riêng cho từng khu hệ. Các khu hệ cá thể hiện rõ tính chất nước lợ điển hình của các thuỷ vực cửa sông, đầm phá ven biển. Có 4 loài cá quý hiếm được ghi trong sách đỏ Việt Nam 2007 ở mức độ rất nguy cấp

    Preparation, Characterization, and Antibacterial Activity of Silver Nanoparticle-Decorated Ordered Mesoporous Carbon

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    In this study, Ordered Mesoporous Carbon (OMC) was prepared using resol as a carbon precursor and F127 as a soft template. Small-angle X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM) images, and nitrogen adsorption and desorption isotherms revealed that OMC possessed ordered hexagonal mesostructures (p6m) with an ordered pore size of 3.2nm, a high specific surface area (SBET) of 539m2/g, and a large total pore volume (Vtotal) of 0.44cm3/g. Subsequently, silver nanoparticles synthesized from an aqueous AgNO3 solution using glucose as a reducing agent and starch as a stabilizing agent were decorated on OMC, producing Ag/OMC. XRD analysis revealed that the composite contained silver crystals. In addition, the content and size of silver nanoparticles in Ag/OMC were 0.71wt% (AAS) and around 25-50nm (TEM), respectively. Due to the surface cover of silver nanoparticles, SBET and Vtotal of Ag/OMC slightly decreased to 417m2/g and 0.38cm3/g, respectively. Both agar and broth dilution techniques were used to evaluate the antibacterial activity of the material against Staphylococcus aureus. Ag/OMC with a Minimum Inhibitory Concentration (MIC) of 25.0μg/mL is a potential candidate for use against Staphylococcus aureus

    Effect of time and temperature on the survival rate of mouse sperm (Mus musculus var. Albino) in short-term preservation without cryoprotectant agents

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    In this study, we studied the use of physiological saline solution (NaCl 0,9%) or dulbecco’s phosphatebuffered saline (D-PBS) for mature sperms short-term preservation. After being collected from epididymides, sperms were adjusted to desired concentration (2x106 sperms/ml) with NaCl 0.9% solution or D-PBS solution (the dishes containing sperms were covered by mineral oil) and stored at 4oC, iooC and room temperature (RT/26oC
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