The Prospective Evolution of the Vietnamese Power Sector: The Vulnerability and Externality Analysis

With its rapidly increasing power demand of 16% p.a since 1990s along with its limited supply power capacity, how sustainable is Vietnam's electricity development? What are the major factors explaining its performance relative to other Asian countries? To answer these questions, this paper examines the Vietnamese power system from the 1990s to 2040 by using LEAP simulation. Twelve vulnerability and externality indexes regarding social-economic-environmental dimensions are calculated to assess vulnerability levels of the sector in seven scenarios. External costs of CO2, NOx, SO2 and PM10 are calculated to examine how far the costs could affect on the electricity cost in Vietnam. In sensitivity analysis, the paper assesses the impacts of international coal price's fluctuations on the electricity price and the trade balance of Vietnam. The study confirms that Vietnam's power sector will become more vulnerable to fossil fuels' prices, environmental pollutants and climate change if the sector goes for the current policy pathways. With the efficiency scenarios examined in the study, the sector would be more independent and less vulnerable. To reduce the vulnerabilities, the study suggests that Vietnam should promote energy efficiency and electricity generation from non-fossil fuels and internalize external costs into the power sector. Vietnam needs also get involved in international financial mechanisms for clean development and technology transfer programs to efficiently exploit its renewable energy potentials

Experiences of Renal Stone Fragmentation with the Use of the Ultrasound-guided Mini-percutaneous Nephrolithotipsy in 650 Patients

AIM: This study assesses the results of treatment using the mini-percutaneous nephrolithotipsy (PCNL) procedure on renal stone patients in a lateral position under ultrasound guidance, performed at the Ha Noi Hospital of Post and Telecommunications. METHODS: The study was conducted with 650 kidney stone patients who were treated using the ultrasound-guided mini-PCNL procedure in a lateral position, at the Ha Noi Hospital of Post and Telecommunications, over the period from June 2018 to June 2019. RESULTS: For the 650 patients, the mean age was 47.3 ± 7.6 (from 21 to 91 years old); the mean size of stones: 19.4 ± 1.2 mm (from 12 mm to 60 mm); the mean operative time: 49.3 minutes (from 37 to 90 min); the mean period of hospitalization: 3.9 days (from 3 to 12 days); the mean stone-free rate (SFR): 90.6%; the rate of second surgery: 1.07%; hemorrhage complication: 0.8%; urinary tract infections: 7.7%; septicemia: 0.6%; administered open surgery: 0.46%; and administered other methods: 0.76%. CONCLUSION: Renal stone fragmentation using the mini-PCNL procedure, performed on patients placed in lateral position under ultrasound guidance, is a method that is effective, beneficial, and safe for patients with renal stones and upper ureteral stones

Offshore Wind Data Integration

Doktorgradsavhandling i informasjons- og kommunikasjonsteknologi, Universitetet i Agder, Grimstad, 2014Using renewable energy to meet the future electricity consumption and to reduce environmental impact is a significant target of many countries around the world. Wind power is one of the most promising renewable energy technologies. In particular, the development of offshore wind power is increasing rapidly due to large areas of wind resources. However, offshore wind is encountering big challenges such as effective use of wind power plants, reduced cost of installation as well as operation and maintenance (O&M). Improved O&M is likely to reduce the hazard exposure of the employees, increase income, and support offshore activities more efficiently. In order to optimize the O&M, the importance of data exchange and knowledge sharing within the offshore wind industry must be realized. With more data available and accessible, it is possible to make better decisions, and thereby improve the recovery rates and reduce the operational costs. This dissertation proposes a holistic way of improving remote operations for offshore wind farms by using data integration. Particularly, semantics and integration aspects of data integration are investigated. The research looks at both theoretical foundations and practical implementations. As the outcome of the research, a framework for data integration of offshore wind farms has been developed. The framework consists of three main components: the semantic model, the data source handling, and the information provisioning. In particular, an offshore wind ontology has been proposed to explore the semantics of wind data and enable knowledge sharing and data exchange. The ontology is aligned with semantic sensor network ontology to support management of metadata in smart grids. That is to say, the ontology-based approach has been proven to be useful in managing data and metadata in the offshore wind and in smart grids. A quality-based approach is proposed to manage, select, and provide the most suitable data source for users based upon their quality requirements and an approach to formally describing derived data in ontologies is investigated

Development Of Palm Kernel Oil Polyol - Based Shape Memory Polyurethane With Polyethylene Glycol (Peg) And Poly Caprolactone (Pcl) As Soft Segment

Shape memory polyurethanes (SMPU) is one of the most notable and common shape memory polymer (SMP), and its composites has gained attention due to the enhancement in both shape memory and mechanical properties. In addition, as the awareness of sustainable development, environmental issues, and fossil fuel depletion, palm kernel oil polyol (PKO-p) - based SMPU and its relative composite reinforced with graphene nanoplatelets (GNPs) were synthesized and characterized in this study. Both SMPU and its composite samples were fabricated using two-step pre-polymerization method. A series of SMPU with different type, molecular weight (MW), and molar ratio of long chains polyol (polycaprolactone diol (PCL) and polyethylene glycol (PEG)) was synthesized and analyzed. The results pointed out that PU-PEG samples (PKO-p - based SMPU with PEG as the long chain polyol) exhibited better shape fixity but low tensile strength which is due to the high crystallinity of PEG and extremely high degree of phase separation (DPS) whereas PU-PCL samples (PKO-p - based SMPU with PCL as the long chain polyol) were not able to show shape fixability but exhibited better tensile strength and flexibility due to the effect of phase mixing. The type of polyols attributed significantly to the shape memory properties while the MW had a slight effect on its properties. PU-PCLPEG samples with the combination of PCL and PEG as soft segments overcame the drawbacks of PU-PCL and PU-PEG samples. For the fabrication of SMPU composites, GNPs was functionalized by acid treatment and evaluated using several analyses (Fourier transform infra-red, Zeta potential, Filed-emission scanning electron microscope, Raman spectroscopy) before incorporating with pre-polymer to produce the composites (varies at 0.25, 0.5, 1.0, 1.5wt% of GNP). With the presence of oxygen-containing functional groups introduced during acid treatment process, treated GNPs dispersed and distributed in polyurethane (PU) matrix was better than the composite with un-treated GNPs, hence results in a remarkable enhancement in mechanical properties, especially the tensile strain at break. Functionalized GNP - based SMPU composite (PU-F) reached maximum tensile strength at 1wt% of functionalized GNP, which is 150% higher compared to that of neat SMPU while tensile strain at break increased 1590% than that of neat SMPU at 0.25wt% functionalized GNP. In contrary, there was a reduction on the modulus of PU-F samples compared with the pristine SMPU, and the modulus was improved significantly when the amount of functionalized GNP reached 1wt%. With regards to the shape properties of all composites, shape fixity was almost similar to that of neat SMPU and all the composite samples recovered completely to their original shape with 100% shape recovery

Perspective of CO2 capture & storage (CCS) development in Vietnam: Results from expert interviews

International audienceThis paper summarizes expert opinions regarding crucial factors that mayinfluence Vietnam’s future use of carbon capture and storage (CCS) based onface-to-face interviews in December 2013 with 16 CCS-related experts fromthe Vietnamese government, research institutes, universities and the energyindustrial sector. This study finds that financial incentives and climate policyare the most important factors for the development of CCS technologies inVietnam in the next two decades. Financial incentives involve direct subsidiesfrom the government, such as tax exemptions for land use and the importationof CCS-related equipment. In addition, all the experts agree that internationalfinancial support is important to initiate a large deployment of CCStechnologies in Vietnam by implementing demonstrative/pilot projects to proveCCS’s working efficiency

Costs and Benefits of a Greener Alternative for the Development of Vietnam's power sector

International audienceIn this study, BAU (a scenario based on current trends) and ALT (a greener alternative with more renewables, higher energy efficiency) are developed. The external costs of CO 2 , NOx, SO 2 and PM 10 in the Vietnamese power sector are estimated at 20, 1328, 2047 and 1460 US$/ton, respectively. The authors find that the electricity price and the domestic trade balance in ALT are less sensitive to fluctuations in the international price of coal than in BAU. The total costs accumulated between period 2010-2040 would be lower in ALT: 632 billion US$ compared with 974 billion US$. This difference arises from several factors: lower investment in new capacity (226 vs 306 billion US$); lower local pollution costs (73 vs 137 billion US$); and lower expenditures on imported fuels (57 vs 115 billion US$). The outcomes of ALT are in accord with the targets in the most recent Green Growth Strategy of Vietnam

Size-dependent behaviour of functionally graded microbeams using various shear deformation theories based on the modified couple stress theory

This study investigates the mechanical behaviours of functionally graded (FG) microbeams based on the modified couple stress theory. The material properties of these beams are varied through beam’s depth and calculated by using classical rule of mixture and Mori–Tanaka scheme. The displacement fields are presented by using a unified framework which covers various theories including classical beam theory, first-order beam theory, third-order beam theory, sinusoidal beam theory, and quasi-3D beam theories. The governing equations of bending, vibration and buckling problems are derived using the Hamilton’s principle and then solved by using Navier solutions with simply-supported boundary conditions. A number of numerical examples are conducted to show the validity and accuracy of the proposed approaches. Effects of Poisson’s ratio, material length scale parameter, power-law index, estimation methods of material properties and slenderness ratio on deflections, stresses, natural frequencies and critical buckling loads of FG microbeams are examined

Low Carbon Scenario for the Power Sector of Vietnam: Externality and Comparison Approach

International audienceIn this paper, BAU (a scenario based on current trends) and ALT (a greener alternative with more renewables, higher energy efficiency) are developed. The external costs of CO2, NOx, SO2 and PM10 in the Vietnamese power sector are estimated at 20, 1328, 2047 and 1460 US$/ton, respectively. The authors find the electricity price and the domestic trade balance in ALT less sensitive to fluctuations in the international price of coal than in BAU. The total costs accumulated between the period of 2010-2040 would be lower in ALT: 632 billion US$ compared with 974 billion US$. This difference arises from several factors: lower investment in new capacity (226 vs 306 billion US$); lower local pollution costs (73 vs 137 billion US$); and lower expenditures on imported fuels (57 vs 115 billion US$). The outcomes of ALT are in accord with the targets in the most recent Green Growth Strategy of Vietnam and the Intended Nationally Determined Contributions (INDCs) of the country to UNFCCC and COP21