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Search Results: 1 - 10 of 5408 matches for " Sy Hung Mai "
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Research on Delay Risks of EPC Hydropower Construction Projects in Vietnam  [PDF]
Mai Sy Hung, Jianqiong Wang
Journal of Power and Energy Engineering (JPEE) , 2016, DOI: 10.4236/jpee.2016.44002
Abstract: In recent years, in Vietnam, economy has been developing rapidly. To ensure rapid and sustainable economic growth, strong support from the energy sector is required. Governments in Vietnam have invested in numerous hydropower projects, many of which employ the EPC (Engineering, Procurement and Construction) contract. However, the EPC general contractors are facing many difficulties, resulting in schedule delays and considerable losses. This research is conducted to highlight the main risk factors in the delays of hydropower construction projects in Vietnam. The research employs the method of statistical calculations and risk analysis to obtain feedback from experts participating in similar projects. The research outcomes are as follows: identifying the risks that can cause delays in EPC hydroelectric construction projects in Vietnam; calculating and classifying the degree of impact of each risk to the progress of the construction. The practical significance of this study is to ensure the timely completion of projects, benefits for the investors, and the EPC general contractors.
Research on Quality Risk of EPC Hydropower Projects in Vietnam  [PDF]
Sy Hung Mai, Jianqiong Wang
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.52024
Abstract: Engineering, procurement and construction (EPC) contracts are on the way to become the most usual form of contracting applied by the private sector to undertake construction works on large scale Hydropower projects. If EPC contract management is not implemented and controlled properly. Quality is the first important factor for any contractors who involve in the hydropower project execution. The purpose of this study is to investigate and evaluate risks causing not good quality of EPC hydropower projects in Vietnam. In addition, the study also provided the recommendations for project practitioners to mitigate the impacts of those identified risks. The findings of this study can be a good managerial reference for project management teams who are working in other countries that have similar economic and investment environments to Vietnam to get their EPC construction project completed on quality, thus will ensuring the benefits to the government, the investors, the contractors, and the parties involved.
Research on Subcontractor Risk of EPC Hydropower Project in Vietnam  [PDF]
Dinh Bui, Sy Hung Mai, Huu Hai Vu
World Journal of Engineering and Technology (WJET) , 2019, DOI: 10.4236/wjet.2019.71003
Abstract: Engineering, procurement and construction (EPC) contracts are becoming the most popular form to undertake construction works on large-scale hydropower projects.The EPC general contractors in Vietnam have been coped with lots of difficulties during the construction phase of hydropower projects, resulting in significant schedule delays and cost overrun. One of the reasons is poor Subcontractors capacity.In order to overcome above, the current study attempts?to research on identification and control Subcontractors risks of delay process of EPC hydropower project in Vietnam.Through summarizing international research achievements of previous researches relating on EPC hydropower projects combining with analysis characteristics of developing construction of EPC hydropower projects in Vietnam, the current study pointed out all kinds of subcontractor risk of delay process of EPC hydropower project in Vietnam;?a questionnaire with 18 risk elements was designed and then delivered to experts in EPC hydropower project management area. Based on the risk model, 11 main risk elements were identified which can be categorized into 3 groups.?Lastly, the current study proposed suggestions to reduce or avoid risks as well as approach to control risks.Furthermore, the findings of this study can be a good managerial reference for project management teams who are working in other countries that have similar economic and investment environment to Vietnam to get their EPC construction project completed on schedule, thus ensuring the benefits to the government, the investor, the contractor, and the parties involved.
Research on Cost Overrun Risk of Construction Phase of Vietnam Highway International Contracting Project  [PDF]
Hong Anh Vu, Jianqiong Wang, Lianxing Min, Sy Hung Mai, Hong Phong Nguyen
Engineering (ENG) , 2016, DOI: 10.4236/eng.2016.83011
Abstract: Recently, the highway construction projects increase rapidly in Vietnam and most of them are international contracting projects. It results serious negative influence on the local government and enterprises that the common cost overrun of projects, and the risk factors of it is different in the different countries, different stages and projects types. So in this paper, we generate an evaluation index system of highway construction projects cost overrun risk in Vietnam in the perspective of different project participants, and also evaluate the effects of these factors in method of regression analysis. The empirical results confirmed 7 main factors that have aggravated cost overrun risk in construction stages, e.g. survey and design scheme risk. In final, the corresponding suggestions are proposed to reduce the project cost overrun risk.
Fault-tolerant Operations for Universal Blind Quantum Computation
Chia-Hung Chien,Rodney Van Meter,Sy-Yen Kuo
Computer Science , 2013,
Abstract: Blind quantum computation is an appealing use of quantum information technology because it can conceal both the client's data and the algorithm itself from the server. However, problems need to be solved in the practical use of blind quantum computation and fault-tolerance is a major challenge. On an example circuit, the computational cost measured in T gates executed by the client is 97 times more than performing the original computation directly, without using the server, even before applying error correction. (The client still benefits due to drastically reduced memory requirements.) Broadbent et al. proposed running error correction over blind computation, but our first protocol applies one layer of Steane's [[7,1,3]] code underneath instead. This protocol has better fault tolerance, but still results in a substantial overhead. We propose another protocol to reduce the client's computational load by transferring the qubit preparation to the server. For each logical qubit used in the computation, the client is only required to receive eight logical qubits via teleportation then buffer two logical qubits before returning one. This protocol also protects the client's fault-tolerant preparation of logical qubits from a side-channel attack.
Advanced Deterioration Diagnosis Model for Building External Wall Tiles  [PDF]
Sy-Jye Guo
World Journal of Engineering and Technology (WJET) , 2018, DOI: 10.4236/wjet.2018.62B001
In 1981 Taiwan entered a period of intense construction, meaning that today many buildings are more than 30 years old. Lack of maintenance has led to frequent safety incidents involving external walls. This study focuses on a deterioration diagnostic model for external wall tiles of aged buildings, using both stage 1 and stage 2 diagnostic methods. The visual test results are categorized based on impact on public safety, and renovation strategies are proposed. Stage 1 diagnosis mainly adopted the DER visual inspection deterioration assessment method. For enhance the accuracy, this research adopted the Infrared Thermal Imaging detection method to double confirm the visual inspection results. After producing an external wall tile Condition Indicator (CI). For stage 1 diagnostic results that fall in a gray area, stage 2 diagnosis was carried out using a tap tone test, followed by fast Fourier transform and pattern recognition to analyze the tapping results. Finally, the study provides a deterioration evaluation criteria for external wall tiles replacement recommendations and a standard operating procedure for deterioration diagnosis. The study also recommends directions for future amendment of regulations, and provides a basis of reference for the government in determining urban renewal, renovation and maintenance strategies.
Modeling Off-Shore Wind Turbine Construction Project Subject to Impact of Wind Uncertainty  [PDF]
Sy-Jye Guo
World Journal of Engineering and Technology (WJET) , 2019, DOI: 10.4236/wjet.2019.72B005
Offshore wind farm is a key item in green energy and sustainable development. The Taiwan strait owns the world-class wind farm with average wind speed of 12 m/s and a potential for 3000 hours/year of power generation. Compared to wind turbines on land, the offshore wind turbine provide more stable power and less obstacles as well as less power loss. The potential and advantages of offshore wind farm development in the Taiwan strait has become the aims of the Taiwan government policy from now to 2025. This research will collect the historical climate data (wind and wave) of the Taiwan offshore wind farm in the Chan-hwa county. Combined the productivity loss respected to the installation of wind turbine due to different wind speed effect, as well as the productivity loss respected to the construction of pile foundation due to different wave height effect, this study will build up a total project duration forecast system based on the historical climate data of the offshore wind farm. Even the literature views from the experienced projects in North Europe including UK, Netherland and Spain, the climate uncertainty still plays a significant factor of the total construction duration for offshore wind farm. The results of this research can provide a more scientific and reliable duration forecast for future offshore wind farms construction in Taiwan.
Pilot plant production of Anti-malarial Drug piperaquine phosphate and synthesis of its metabolites
Nguyen Van Hung,Pham Van Cuong,Doan Thi Mai Huong,Tran Van Hieu
Journal of Analytical Science & Technology , 2011,
Abstract: An optimized, convergent, safe synthesis of piperaquine phosphate (1), an antimalarial agent, as well as synthesis of its main metabolites was described. Major improvements for piperaquine phosphate (1) production were made in the preparation of intermediate 7 by using directly piperazine instead of N-formyl piperazine. The structures of the synthetic compounds were determined from spectral analysis including MS and 2D NMR.
Conduction gap in graphene strain junctions: direction dependence
Mai Chung Nguyen,Viet Hung Nguyen,Huy-Viet Nguyen,Philippe Dollfus
Physics , 2014, DOI: 10.1088/0268-1242/29/11/115024
Abstract: It has been shown in a recent study [Nguyen et al., Nanotechnol. \textbf{25}, 165201 (2014)] that unstrained/strained graphene junctions are promising candidates to improve the performance of graphene transistors that is usually hindered by the gapless nature of graphene. Although the energy bandgap of strained graphene still remains zero, the shift of Dirac points in the \textbf{\emph{k}}-space due to strain-induced deformation of graphene lattice can lead to the appearance of a finite conduction gap of several hundreds meV in strained junctions with a strain of only a few percent. However, since it depends essentially on the magnitude of Dirac point shift, this conduction gap strongly depends on the direction of applied strain and the transport direction. In this work, a systematic study of conduction gap properties with respect to these quantities is presented and the results are carefully analyzed. Our study provides useful information for further investigations to exploit graphene strained junctions in electronic applications.
Enhanced Seebeck effect in graphene devices by strain and doping engineering
Mai Chung Nguyen,Viet Hung Nguyen,Huy-Viet Nguyen,Jerome Saint-Martin,Philippe Dollfus
Physics , 2015, DOI: 10.1016/j.physe.2015.05.020
Abstract: In this work, we investigate the possibility of enhancing the thermoelectric power (Seebeck coefficient) in graphene devices by strain and doping engineering. While a local strain can result in the misalignment of Dirac cones of different graphene sections in the k-space, doping engineering leads to their displacement in energy. By combining these two effects, we demonstrate that a conduction gap as large as a few hundreds meV can be achieved and hence the enhanced Seebeck coefficient can reach a value higher than 1.4 mV/K in graphene doped heterojunctions with a locally strained area. Such hetero-channels appear to be very promising for enlarging the applications of graphene devices as in strain and thermal sensors.
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