Study on point-to-ring corona based gyroscope

We present for the first time a novel gyroscope using circulatory electro-hydrodynamics flow in a confined space. Three point-ring corona actuator is to generate ionic flows in three separated channels and the ionic flows then merge together at a nozzle of the main chamber to create a jet flow. The residual charge of ion winds is removed by a master-ring electrode. By the effect of angular rate, the jet flow handled by a hotwire anemometry is deflected and sensed. Results by both experiment and numerical simulation consistently show good repeatability and stability of the new configuration-based device. Since ion wind is generated by a minimum power, the device does not require any vibrating component, thus the device is robust, low cost and energy consumption

Hydrodynamic Simulations of Circumstellar Envelopes under the Gravitational Influence of a Wide Binary Companion: Comparison Between Circular and Elliptical Orbits

Shapes of circumstellar envelopes around mass losing stars contain information of the very inner region of the envelope where mass loss process takes place. It’s well known that the presence of a binary companion leads to strong influence on the structure of the envelope through orbital motion of the mass losing star and the gravitational interaction of the companion with the stellar wind. To investigate this effect and structures of envelopes, we have performed high resolution hydrodynamic simulations of a wide binary system in a number of orbital configurations. Our simulations clearly show the importance of the equation of state of the gas because in isothermal case the width of the spiral arm is significantly broadened with respect to the ideal gas case, therefore resulting in unrealistic spiral patterns. As the orbital geometry changes from circular to elliptical, our simulation results show that the spiral becomes bifurcated and increasingly asymmetric as indicated in previously published results. In the polar direction, the prominent alternating arcs associated with circular orbital configuration morph into almost continuous circular rings. The physical condition of the gas in the envelope is shown to vary strongly between the spiral arm and inter-arm regions. Our hydrodynamic simulations will be useful to interpret high angular resolution observations of circumstellar envelopes

Factors affecting the decision to choose a university of high school students: A study in An Giang Province, Vietnam

It is important to provide high school students with the necessary information for them to consult and make a decision to choose a university. The study aims to identify and evaluate the influence of factors in the decision to choose a university for high school students. The questionnaire survey method was used to collect data from 393 students from eight high schools in An Giang Province, Vietnam. Exploratory factor analysis and linear regression were used to analyze the data. The research results show that students are quite satisfied and quite certain with their decision to choose a university, while there are six important factors affecting the decision to choose a university. Influential factors with decreasing order of magnitude are: i) Factors consulted by teachers, family, friends, and relatives; ii) Factors of future job opportunities; iii) Factors of media activities; iv) Factors of learning conditions; v) Factors of university reputation; vi) Factors belong to the students themselves. The findings of the study show that there is no statistically significant difference between the group of males and females, between grades 10, 11, and 12. Besides, there is a statistically significant difference between students in high schools. The findings of this study have theoretical and practical implications for university admissions in Vietnam. Proposals made to university administrators were discussed. From the research results, we want to help students find the right university, and support universities to improve the efficiency of admissions

Development of PSO for tracking Maximum Power Point of Photovoltaic Systems

For a photovoltaic system, the relationship of the output voltage and power is usually non-linear, so it is essential to equip a MPPT controller in PV systems. Furthermore, the hotspot problem is a common phenomenon, resulting from the PV system operating under PSC. Partial shading not only damages the PV cells, but also makes it difficult to find the global MPP in the characteristic curves of P-V. The paper proposes a novel version of PSO, namely PPSO in order to detect the global peak among the multiple peaks, known as the true maximum energy from PV panel. For this, the PPSO algorithm makes the velocity of each particle be perturbed once the particles are struck into a local minima state in order to find the best optimum solution in the MPPT problem. The perturbation in the velocity vector of each particle not only helps them tracking the MPP accurately under the changing environmental conditions, such as large fluctuations of insolation and temperature like PSC; but also removes the steady-state oscillation. The proposed approach has been tested on a MPPT system, which controls a dc-dc boost converter connected in series with a resistive load. Moreover, the obtained results are compared to those obtained without any MPPT controller to prove the efficiency of the suggested method. In addition, this novel version gives the highest accuracy of tracking the optimum power in the least iteration number as compared to the conventional PSO

THÀNH LẬP SƠ ĐỒ PHÂN BỐ ĐỨT GÃY KHU VỰC BIỂN VEN BỜ NAM TRUNG BỘ TRÊN CƠ SỞ MINH GIẢI TÀI LIỆU ĐỊA CHẤT - ĐỊA VẬT LÝ

The scheme of the faults in South Central coastal region was established on the basis of interpreting the high resolution shallow seismic data and the deep-seismic data, in combination with the previous studies on geodynamics, tectonic evolution, geological hazards of the South Central coastal region. The fault systems were formed based on updated geophysical, geomorphological, tectonophysic and remote sensing data, including 19 faults in 3 directions: Sub-longitudinal (8 faults), NE-SW (7 faults) and NW-SE (4 faults).Sơ đồ phân bố đứt gãy khu vực biển ven bờ Nam Trung Bộ được thành lập trên cơ sở minh giải, phân tích tài liệu địa chấn nông phân giải cao, địa chấn dầu khí, kết hợp và kế thừa các kết quả nghiên cứu địa chất-địa động lực, tiến hóa kiến tạo. Hệ thống đứt gãy được nghiên cứu, chính xác hóa từ các tài liệu địa vật lý, địa chất-địa mạo, vật lý kiến tạo, viễn thám mới nhất. Trong khu vực có 19 hệ đứt gãy, phát triển theo 3 hướng chính là á kinh tuyến (8 hệ đứt gãy), đông bắc -tây nam (7 hệ đứt gãy) và tây bắc - đông nam (4 hệ đứt gãy)

Tannins: Extraction from Plants

The chapter presents mainly on different extraction methods of tannin. Some technical means required for effective extraction are also presented, for example, collection and treatment of plant and drying and storage of plant. Opportunity and challenges in application of extraction methods are also exhibited in the chapter

Recent geodynamic characteristics of the Southern Central coast and the relations with geological hazards

Recent geodynamic characteristics of the Southern Central coast are analyzed on the basis of vertical and horizontal displacement velocities along active fault zones. The horizontal displacement velocity varies in magnitude from this fault system to another fault system, from 0.11–0.3 mm/year on the strike-slip - normal faults to 0–0.058 mm/year on the strike-slip faults and normal faults. The subsidence velocity changes complicatedly, different from one fault to another fault, depending on the mechanism of faults. On the continental shelf, most of the values of high subsidence’s velocity are related to the normal and strike-slip faults. Subsidence activities make the sea level increase highly, the subsidence activity makes the sea level rise at structures that fall close to the shore, reach about 0.2–0.48 mm/year in late Pleistocene - Holocene. The increase of sea level directly affects the intensity of erosion, flood, salinity and land loss events in coastal lowlands. Slippage of the seabed, earthquakes, volcanoes are geological hazards directly related to the geodynamic regime of the Southern Central coast

Synthesize and characterization of artificial human bone developed by using nanocomposite

The combination of biopolymers with bioceramics plays vital role in development of artificial bone. Hydroxyapatite is extensively used as a material in prosthetic bone repair and replacement. In this paper synthesis of Hydroxyapatite- Polymethyl methacrylate – Zirconia (Hap-PMMA-ZrO2) composite by using powder metallurgy technique. The mechanical, morphological, In-vitro biocompatibility and tribological properties were characterized by universal testing machine, micro-vickers hardness tester, high resolution transmission electron microscope (HR-TEM), MTT assay and pin-on-disc setup. In-vitro cytotoxicity test on HeLa cell lines shows cell viability constant when doses concentration increases so material found non-toxic. Results show that micro Vickers hardness i.e. 520 approximately matches with natural human bone i.e. 400. Compressive strength is less as compared to human bone because of powder metallurgy route used for fabrication and is 74 MPa. Density of proposed composite artificial human bone i.e. 1.52 g/cc is less as compared to natural bone i.e. 2.90 g/cc. The Hap-PMMA-ZrO2 composite will be good biomaterials for bone repair and replacement wor

Neuromuscular Blockade Agents Reversal with Sugammadex Compared to Neostigmine in the Living Kidney Donors

Backround: The reversation of NMBA (neuromuscular blocking agents) prevents numerous postoperative complications, increases quality of recovery and decreases the time, expenditure spending in hospital. The choice of medicine used to reverse NMBA depends  considered as a key fators to gain the best outcome and to avoid the side effects. Aim: To evaluate the postoperative effect on muscle relaxation reversal and side effects of sugammadex 2 mg/kg versus the combination of  neostigmine and atropine sulfate in the living kidney donors. MethodS: A randomised controlled trial on 70 patients undergoing living kidney donation surgery were allocated to 2 groups. Patients in group I (SUGA) were reversed with sugammadex 2 mg/kg and in group II (NEO/ATR) with the combination of neostigmine and atropine sulfat. Results: With 35 patients in each group, the study results showed that after 3 mintutes of reversal patients reaching TOF value ≥ 0.9 in group SUGA is 91.4%, after 5 minutes 100% of patients in group SUGA reached TOF value ≥ 0.9 . In group NEO/ATR after 3 minutes 28.6% patients reached TOF ≥ 0.9 and 40% patients reached TOF≥ 0.9 after 5 minutes. The difference in percentage of patients reaching TOF ≥ 0.9 after 3 minutes, 5 minutes of reversal between two groups is significant (p<0.05). After 10 minutes, 100% patients in both group got TOF ≥ 0.9. Time to exutubation of group SUGA was 249.43 ± 81.75 seconds and it was 456.29 ± 146.45 seconds in group NEO/ATR. Nausea, bradycardia, and increased phlegm production in group NEO/ATR was 22.9%; 28.5%; 25.7% respectively; while those side effects were not met in group SUGA, the difference was significant (p<0.05). Conclusion: The muscle relaxation reversal effect of sugammadex was faster than that of neostigmine, the duration TOF ≥ 0.9 and the time to extubation was significantly faster. Sugammadex did not cause hemodynamic changes before and after muscle relaxation reversal, neostigmine resulted in the bradycardia, increased phlegm secreting and other side effects. The renal function after 24 hours postoperatively of two groups was similar