122 research outputs found

    Stability of Cracked Plates with Nonlinearly Variable Thickness Resting on Elastic Foundations

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    In this paper, the stability of rectangular cracked plates with nonlinearly variable thickness resting on the elastic foundations is studied. The thickness of the plate varies exponentially along the x-axis. Meanwhile, the elastic foundation is modeled by a two-parameter Pasternak elastic foundation type. The crack is assumed at the center of the plate with variable length and angle of inclination. The establishment of the stability equations of the cracked plate is based on the Higher Order Shear Deformation Theory (HSDT) combined with the phase field theory. Next, using the finite element method to solve the equations to find the minimum force that causes plate instability. To test the reliability of the computational theory, the results are compared with several reputable published papers. Then, the article will investigate the influence of elastic foundation, crack location, crack length and crack inclination on the stability of plate. The results show that the elastic foundation has a great influence on the plate stability, while the crack inclination angle has less influence. Finally, there are some images of the destabilization patterns of cracked plates placed on an elastic foundation

    Modelling and Experimental Validation of a VNT Turbocharger for Improving Performances of a Marine Diesel Generator Engine

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    This paper presents modelling and experimental validation for improving the performances of a marine diesel generator engine. Based on the diesel engine theory, the laws of conservation of energy, and the principle of movement of flow through turbocharger nozzle, a mathematical model of a real turbocharged engine was built, concentrating on the mathematic model of flow through nozzles. This model is simulated by Matlab/Simulink program, the results of simulation showed the relationships between the engine and the turbocharger, the turbine and the compressor, and between the nozzles and the turbocharger. The experiments were carried out to validate this model, the errors between the simulation and measure were acceptable. The measure and simulation results also determined that at the low load conditions (≤50% load) engine performances can be improved by adjusting nozzle opening degree (from fully opening to 90% and 80% opening)

    Stability of Cracked Plates with Nonlinearly Variable Thickness Resting on Elastic Foundations

    Get PDF
    In this paper, the stability of rectangular cracked plates with nonlinearly variable thickness resting on the elastic foundations is studied. The thickness of the plate varies exponentially along the x-axis. Meanwhile, the elastic foundation is modeled by a two-parameter Pasternak elastic foundation type. The crack is assumed at the center of the plate with variable length and angle of inclination. The establishment of the stability equations of the cracked plate is based on the Higher Order Shear Deformation Theory (HSDT) combined with the phase field theory. Next, using the finite element method to solve the equations to find the minimum force that causes plate instability. To test the reliability of the computational theory, the results are compared with several reputable published papers. Then, the article will investigate the influence of elastic foundation, crack location, crack length and crack inclination on the stability of plate. The results show that the elastic foundation has a great influence on the plate stability, while the crack inclination angle has less influence. Finally, there are some images of the destabilization patterns of cracked plates placed on an elastic foundation

    Farmers’ own assessment of climate smart agriculture: Insights from Ma village in Vietnam

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    The project Integrated agricultural technologies for enhanced adaptive capacity and resilient livelihoods in climate-smart villages (CSVs) of Southeast Asia aims to provide climate-smart agriculture (CSA) options to enhance adaptive capacity and resilience among CSV farmers and stakeholders. In 2016, in Ma village in Vietnam, one of the CSVs in the region, monitoring and evaluation (M&E) activities focused on the social dimension of the action research: how key actors involved in the research are experiencing progress, costs and benefits, achievements and challenges. To date, M&E of the biophysical dimension by scientists and farmers has received little attention. Although scientists have developed a coherent analytical CSA framework that guides the field research, so far they have struggled to practically track and measure outcome results in a systematic way. This report documents and reflects on how woman and man farmers in Ma village are assessing the biophysical results of the climate-smart techniques and practices they have adopted. They do this mostly through direct observation, some measurement, “before and after” comparison, and some comparison with what neighbours are doing. Overall, farmers’ assessment appears positive despite the lack of quantitative precision to support their judgement. There is work to do for the CSA scientists

    Mechanism of beach erosion at the west of Phu Quoc Island, Southern Vietnam

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    Phu Quoc Island locates in Gulf of Thailand, Southern Vietnam. Several years ago, due to the effect of climate change and the development ofbeach tourism, beach erosion in the Western beach occurred seriously.ReferencesOceanography monitoring data at Phu Quoc Station from 1979 to 2010, National Institute of Hydrology and Meteorology, Ha Noi March 2011.Duriyapong F. and Nakhapakorn K., 2011. “Coastal vulnerability assessment: a case study of Samut Sakhon coastal zone”, Songklanakarin J.Sci. Technol. 33 (4), p469-476.Krystian W. Pilarczyk, Ryszard B. Zeidler, 1996. Offshore breakwaters and shore evolutioncontrol.Le Hoai Nam, 2013. Coastal erosion at PhuQuoc Island from 1979-2010, Doctoraldissertation, Ho Chi Minh City University ofScience.Nicole Hacking, 1998. Macrofaunalcommunity structure of beaches in northern NewSouth Wales, Australia, Mar. Freshwater Res., 49,page 47-53.Mike 21 User Manual and Mike 21/3FMScientific Reference Manual.http://vi.wikipedia.org/wiki/T%E1%BA%ADp_tin:Phu_quoc_1.jp

    Smart Shopping Assistant: A Multimedia and Social Media Augmented System with Mobile Devices to Enhance Customers’ Experience and Interaction

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    Multimedia, social media content, and interaction are common means to attract customers in shopping. However these features are not always fully available for customers when they go shopping in physical shopping centers. The authors propose Smart Shopping Assistant, a multimedia and social media augmented system on mobile devices to enhance users’ experience and interaction in shopping. Smart Shopping turns a regular mobile device into a special prism so that a customer can enjoy multimedia, get useful social media related to a product, give feedbacks or make actions on a product during shopping. The system is specified as a flexible framework to take advantages of different visual descriptors and web information extraction modules. Experimental results show that Smart Shopping can process and provide augmented data in a realtime-manner. Smart Shopping can be used to attract more customers and to build an online social community of customers to share their interests in shopping

    Frequency and Risk Factor of Lower-limb Deep Vein Thrombosis after Major Orthopedic Surgery in Vietnamese Patients

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    BACKGROUND: Deep venous thrombosis (DVT) is a prevalent complication of orthopedic surgery. According in many studies. The incidence of DVT may be up to 50% if thromboprophylaxis is not available. AIM: The objective of this study was to check the degree of disease, clinical characteristics and analyzed factors in vulnerabilities with lower-limp DVT after orthopedic surgery in a Vietnam teaching hospital. METHODS: Orthopedic patients who met criteria were recruited at our hospital between August 2017 and June 2018. Ultrasound was used to discovering lower-limp DVT in pre-surgery and 7 days after surgery in all patients. RESULTS: The incidence of DVT after orthopedic surgery was 7.2%. Patients with older age (> 60) have a risk of 2 times higher of DVT after surgery than normal people (p < 0.05). The incidence of postoperative DVT was higher in immobile individuals > 72 hours (p < 0.05). Patients with prolonged surgical time (>120 minutes) had a higher risk of postoperative DVT than non-surgical patients’ surgery (p < 0.05). CONCLUSIONS: DVT remains a common complication following orthopedic surgery. Older age, immobility status, and surgical time have been found to be risky factors for the development of postoperative lower-limp DVT in orthopedic patients

    Barriers to implementing climate policies in agriculture: A case study from Viet Nam

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    This paper takes an in-depth look at the agricultural sector in Viet Nam, contributing to a better understanding of the main bottlenecks in implementing the Paris Agreement, evaluating the relevance and impact of selected barriers for the implementation of current climate policies and their implications for nationally determined contribution (NDC) design
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