187 research outputs found

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

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    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.TheauthorsfindthattheelectricitypriceandthedomestictradebalanceinALTarelesssensitivetofluctuationsintheinternationalpriceofcoalthaninBAU.Thetotalcostsaccumulatedbetweenperiod2010−2040wouldbelowerinALT:632billionUS/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.Thisdifferencearisesfromseveralfactors:lowerinvestmentinnewcapacity(226vs306billionUS. 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);andlowerexpendituresonimportedfuels(57vs115billionUS); 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

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

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    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

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

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    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.TheauthorsfindtheelectricitypriceandthedomestictradebalanceinALTlesssensitivetofluctuationsintheinternationalpriceofcoalthaninBAU.Thetotalcostsaccumulatedbetweentheperiodof2010−2040wouldbelowerinALT:632billionUS/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.Thisdifferencearisesfromseveralfactors:lowerinvestmentinnewcapacity(226vs306billionUS. 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);andlowerexpendituresonimportedfuels(57vs115billionUS); 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

    Data Driven Customer Segmentation for Vietnamese SMEs in Big Data Era

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    Almost Vietnamese big businesses often use outsourcing services to do marketing researches such as analysing and evaluating consumer intention and behaviour, customers’ satisfaction, customers’ loyalty, market share, market segmentation and some similar marketing studies. One of the most favourite marketing research business in Vietnam is ACNielsen and Vietnam big businesses usually plan and adjust marketing activities based on ACNielsen’s report. Belong to the limitation of budget, Vietnamese small and medium enterprises (SMEs) often do marketing researches by themselves. Among the marketing researches activities in SMEs, customer segmentation is conducted by tools such as Excel, Facebook analytics or only by simple design thinking approach to help save costs. However, these tools are no longer suitable for the age of data information explosion today. This article uses case analysing of the United Kingdom online retailer through clustering algorithm on R package. The result proves clustering method’s superiority in customer segmentation compared to the traditional method (SPSS, Excel, Facebook analytics, design thinking) which Vietnamese SMEs are using. More important, this article helps Vietnamese SMEs understand and apply clustering algorithm on R in customer segmenting on their given data set efficiently. On that basis, Vietnamese SMEs can plan marketing programs and drive their actions as contextualizing and/or personalizing their message to their customers suitabl

    Feasibility and sustainability of co-firing biomass in coal power plants in Vietnam

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    International audienceThe technology of co-firing biomass with coal is well-matured as demonstrated in many power plants in Europe and the US. It is considered as a relatively low-cost technology to utilize biomass in power generation as well as to reduce the greenhouse gases emissions and coal consumption in coal power plants. However, biomass co-firing is still a new concept in the context of Vietnam energy sector. By 2030, the capacity of coal power plants in Vietnam will be expanded to 75 GW, which accounts for 57% of total power generation. This will increase the greenhouse gases emissions and pose a great challenge on coal supply for Vietnam. This research aims to evaluate the feasibility and sustainability of co-firing biomass in coal power plants in Vietnam. The assessment is conducted using a set of indicators, which is divided into four categories: technical, economical, environmental and social aspects. The feasibility and sustainability assessment is then applied to a case study, a newly constructed 1000 MW fluidized bed coal power plant in Quang Ninh Province. In the case study, direct co-firing technology with 5% of biomass co-fired percentage is selected for the evaluation of the indicators

    Structural, Mechanical, Electronic and Thermodynamic Analysis of Calcium Aluminum Silicate Crystalline Phases in Stone Wool Insulation Materials: A first-principles study

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    Stone wool materials have gained considerable attention due to their effectiveness as thermal and acoustic insulation solutions. The comprehension of crystal structure properties is pivotal in determining the overall performance of these materials, as it enables us to optimize their composition for enhanced insulating capabilities. Crucial factors such as structural, mechanical, and thermodynamic characteristics of crystalline phases within stone wool are vital for evaluating its thermal and acoustic insulation properties. This study investigates the properties of calcium aluminum silicate crystal phases commonly present in stone wool, including anorthite, svyatoslavite, scolecite, and dehydrated scolecite using density functional theory (DFT) calculations. In comparison to previous works, this study provides a more comprehensive analysis using advanced DFT calculations. Our analysis reveals the complex interplay between the crystal structures and mechanical behavior of these phases. The calculated bulk modulus of the phases varies significantly, ranging from 38 to 83 GPa. We have compared the calculated elastic properties with available experimental data and found excellent agreement, confirming the accuracy of the computational approach. Moreover, we find that polymorphism has a significant impact on the mechanical strength, with anorthite exhibiting higher strength compared to svyatoslavite. Furthermore, dehydration is found to cause a reduction in unit volume and mechanical strength. The thermodynamic properties of dehydrated scolecite, including entropy and heat capacity, are significantly lower due to the absence of water molecules. These findings highlight the importance of understanding the structural and mechanical characteristics of calcium aluminum silicate phases in stone wool materials. Additionally, our findings have broader implications in various industries requiring effective insulation solutions such as to develop new materials or to enhance the energy efficiency of existing insulating products. © 2023 The Author(s)publishedVersio

    Elastic and thermodynamic properties of the major clinker phases of Portland cement: Insights from first principles calculations

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    Portland based cement is one of the most popular materials used in the civil and construction applications. Reliable computational methods to provide an insight into the underlying mechanics of the major phases of this material are of great interest for cement design. The present work investigated the performance of density functional theory (DFT) calculations using the PBE-D2 method to predict the mechanical, thermodynamic properties of four major phases namely Alite C3S, Belite C2S, tricalcium aluminate C3A and tetracalcium aluminoferrite C4AF. The calculated elastic properties were in a good agreement with available experimental data. In addition, a deeper insight into the electron density of state, spin-polarization, atomic charge, as well as free energy and entropy properties were also presented. Further development is necessary to improve the established DFT models for predicting the mechanical properties of the ferrite phase of Portland clinker.publishedVersio

    THE AMOUNT AND SPECIATION OF TRACE ELEMENTS TRANSPORTED FROM RICE FIELD TO CANAL DURING A FLOODING EVENT

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    Trace element pollution of soils, sediments and surface water can pose a risk for the local population and the environment of Vietnam. Rice fields can be affected by storm events, which cause the release of trace elements into surface water and transport them into drinking wells. The aim of this study was to investigate if dissolved and suspended As, Pb and Zn concentrations in surface water of a paddy rice fields and an irrigation canals increased during a flooding event and exceed the Vietnamese Surface Water Quality Standards and WHO Guidelines for Drinking-water Quality. The study site is a rice field area in the Thanh Hoa province in Central Vietnam, which experiences an average of 2.4 storms every year causing overflow of streams and low-order canals. Concentrations of As increased during the flooding event with dissolved As being the prevailing fraction, which followed a late flush behavior. Lead showed no significant difference in concentration over time. Zn concentrations only increased significantly in the canal upstream the field in the morning of the first day. Suspended Zn dominated at that time, following the first flush behavior of TSS concentrations. Concentrations of As, Pb and Zn did not exceed the Vietnamese Surface Water Quality Standards or WHO Guidelines for Drinking-water Quality at any time and they are therefore of no concern for the health of the local populatio

    Phosphate Adsorption by Silver Nanoparticles-Loaded Activated Carbon derived from Tea Residue.

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    This study presents the removal of phosphate from aqueous solution using a new silver nanoparticles-loaded tea activated carbon (AgNPs-TAC) material. In order to reduce costs, the tea activated carbon was produced from tea residue. Batch adsorption experiments were conducted to evaluate the effects of impregnation ratio of AgNPs and TAC, pH solution, contact time, initial phosphate concentration and dose of AgNPs-AC on removing phosphate from aqueous solution. Results show that the best conditions for phosphate adsorption occurred at the impregnation ratio AgNPs/TAC of 3% w/w, pH 3, and contact time lasting 150 min. The maximum adsorption capacity of phosphate on AgNPs-TAC determined by the Langmuir model was 13.62 mg/g at an initial phosphate concentration of 30 mg/L. The adsorption isotherm of phosphate on AgNPs-TAC fits well with both the Langmuir and Sips models. The adsorption kinetics data were also described well by the pseudo-first-order and pseudo-second-order models with high correlation coefficients of 0.978 and 0.966, respectively. The adsorption process was controlled by chemisorption through complexes and ligand exchange mechanisms. This study suggests that AgNPs-TAC is a promising, low cost adsorbent for phosphate removal from aqueous solution

    The immunogenicity of plant-based COE-GCN4pII protein in pigs against the highly virulent porcine epidemic diarrhea virus strain from genotype 2

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    Porcine epidemic diarrhea virus (PEDV) is a serious infectious causative agent in swine, especially in neonatal piglets. PEDV genotype 2 (G2) strains, particularly G2a, were the primary causes of porcine epidemic diarrhea (PED) outbreaks in Vietnam. Here, we produced a plant-based CO-26K-equivalent epitope (COE) variant from a Vietnamese highly virulent PEDV strain belonging to genotype 2a (COE/G2a) and evaluated the protective efficacy of COE/G2a-GCN4pII protein (COE/G2a-pII) in piglets against the highly virulent PEDV G2a strain following passive immunity. The 5-day-old piglets had high levels of PEDV-specific IgG antibodies, COE-IgA specific antibodies, neutralizing antibodies, and IFN-γ responses. After virulent challenge experiments, all of these piglets survived and had normal clinical symptoms, no watery diarrhea in feces, and an increase in their body weight, while all of the negative control piglets died. These results suggest that the COE/G2a-pII protein produced in plants can be developed as a promising vaccine candidate to protect piglets against PEDV G2a infection in Vietnam
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