An economic analysis of sweet potato production and utilization for animal feed on North Vietnam

The study aimed to determine the effects of government policies on the incentive structure of the sweet potato industry. It reviewed the national program on sweet potato production and the government policies in the input and output markets of the sweet potato industry and related these to the question of whether or not the country has comparative advantage in sweet potato production. The nominal protection rate (NPR) was used as measure of production incentive. On the other hand, the comparative advantage study focused on the concept of net social profitability (NSP). Results showed that government policies provided incentives to sweet potato growers, as indicated by the NPR values which ranged from 7 - 25 percent. However, these also served as disincentives for sweet potato growers by imposing positive implicit tariff (IT) on major inputs (e.g., fertilizer) used for sweet potato production. The NSP values in all study areas were positive, showing that sweet potato production in North Vietnam had comparative advantage, or sweet potato production in the study areas used domestic resources more efficiently. The largest NSP value was three thousand five hundred seventeen point five dong and the smallest value was one hundred eight-two dong per hectare of sweet potato in Hatay and Hanoi, respectively. The study also evaluated the prospects of using sweet potato products (roots and vines) were mainly used for swine feed. The largest proportion of roots used as feed was 82.1 percent and the smallest was 50.2 percent in Hatay and Thanhhoa, respectively. For sweet potato vine, the highest proportion used was 80.8 percent in Thanhhoa and the lowest was 54.5 percent in Hanoi. Sweet potato occupied a large part in total feeds costs for swine: 16.5 - 33.6 percent in Bacthai and 29.1 - 45.1 percent in Thanhhoa. Weight gains of swine fed with sweet potato, which has good supplemental protein, was at par with those given commercial feeds. The study showed that using sweet potato as the main feed ingredient for swine

Catalytic upgrading of biomass pyrolysis vapours using Faujasite zeolite catalysts

Bio-oil produced via fast pyrolysis of biomass has the potential to be processed in a FCC (fluid catalytic cracking) unit to generate liquid fuel. However, this oil requires a significant upgrade to become an acceptable feedstock for refinery plants due to its high oxygen content. One promising route to improve the quality of bio-oil is to pyrolyse the parent biomass in the presence of a catalyst. This work investigates the influence of faujasite catalysts on the pyrolysis of pinewood. Pyrolysis process with Na-faujasite, Na0.2H0.8-faujasite, and H-faujasite (Na-FAU, Na0.2H0.8-FAU, and H-FAU) were carried out in a fixed-bed reactor at 500 °C. It is shown that, in the same condition, catalytic upgrading of pyrolysis vapour is superior to in-situ catalytic pyrolysis of biomass when it comes to quality of bio-oil. The yields of coke, gas and water increase while that of organic phase decreases proportional with the concentration of protons in catalysts. Compared to the other two catalysts, Na0.2H0.8-FAU removes the most oxygen from bio-oil, reduces amount of acids and aldehydes/ketones which result in a higher energy-contained and more stable oil with less corrosive property. However, the biggest contribution to the oxygen removal is via the formation of reaction water, which is not an optimum path. This leaves space for future development

Effects of Air Entrainment on Fluid Transients in Pumping Systems

In pumping installations, fluid transient computations are necessary to achieve safety, efficiency and economy in design and operation. In some systems, where air content and air entrainment exist, such computations become highly inaccurate when constant wave speed is assumed. In this paper, a numerical model and a computational procedure have been developed to investigate the effects of air entrainment on the pressure transient in pumping systems. Free gas in the fluid and cavitation at the fluid vapour pressure were modeled in the form of variable wave speed model, which was numerically solved by the method of characteristics. This model was tested for the case of pump trips due to power failures. The pressure transient results obtained by this variable wave speed model were analyzed and compared with those results obtained by constant wave speed model and with the experimental results of other investigators

Soil health impacts of rubber farming: The implication of conversion of degraded natural forests into monoculture plantations

High revenues from rubber latex exports have led to a rapid expansion of commercial rubber cultivation and, as a consequence, the conversion of different land use types (e.g., natural forests) into rubber plantations, which may lead to a decrease in soil health. In this study in Quang Tri Province, Vietnam, we determined: (1) the variation of soil health parameters along a chronosequence of rubber tree stands and natural forests and (2) the relationships and potential feedback between vegetation types, vegetation structures and soil health. Our results revealed that: (1) soil health was higher in natural forests than in rubber plantations with a higher values in higher biomass forests; (2) soil health was lower in younger rubber plantations; (3) soil health depends on vegetation structure (with significantly positive relationships found between soil health and canopy cover, litter biomass, dry litter cover and ground vegetation cover). This study highlights the need for more rigorous land management practices and land use conversion policies in order to ensure the long-term conservation of soil health in rubber plantations

Introducing an agricultural app to urban vegetable farmers: a pilot study in Hanoi

Plantix is an agricultural app which offers diagnosis and advice for more than 30 crops. It was developed by a private company based in Germany. It has a great potential as a new form of extension service complementing a traditional face-to-face extension service. CGIAR’s Plant Health Initiative seeks to introduce the app as part of a package of innovations available for integrated pest and disease management to facilitate farmers’ behavioral change. Plantix has been widely used in India, but it has not been very common yet in Vietnam. The aim of this pilot study is to test the usability of Plantix app for urban vegetable growers in Hanoi, Vietnam. 12 farmers (6 women and 6 men) participated in the training on how to use the app and provided feedback after a two-week trial. Results show that both women and men farmers are greatly interested in using the app. Some farmers purchased and sprayed appropriate pesticides following advice from the app. Each participant shared the app with 2-5 relatives, friends and/or neighbors. Women shared the app with their husbands as well as their female peers, while men tended to share it with their male peers. Although this pilot study confirms the usability of the app in the urban context of Vietnam with few constraints in access to internet and digital literacy for both women and men, some adjustments are required to meet their needs and to fit with the context

Freshwater Ecosystems: From Models to Applications

Freshwater ecosystems—lakes and streams—are being endangered by agricultural, urban, and industrial pollution; hydraulic engineering; and overexploitation, which threaten their capacity to provide important services (recreation and supply of food and clean water, among others). Ecological modeling may be employed to estimate impacts and analyze mitigation strategies. Toy models are easy to construct, but applying them to real-world problems is often challenging. Here, we show in two case studies how the connection from model to application can be made. The first study analyzes whether and how the impact of climatic change on a mostly recreational fishery in an Alpine lake can be mitigated, while the second looks at restoring biodiversity after cleaning up pollution in a Korean river system, using aquatic insects, which play an essential functional role in aquatic food-webs and are very sensitive to water quality, as indicators of ecosystem health. These studies highlight the ability of process-based eco-evolutionary models to generate testable hypotheses and contribute solutions to real-world problems

Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository—BMT1 of the DECOVALEX III project. Part 1: Conceptualization and characterization of the problems and summary of results

11 pagesInternational audienceGeological disposal of the spent nuclear fuel often uses the concept of multiple barrier systems. In order to predict the performance of these barriers, mathematical models have been developed, verified and validated against analytical solutions, laboratory tests and field experiments within the international DECOVALEX III project. These models in general consider the full coupling of thermal (T), hydraulic (H) and mechanical (M) processes that would prevail in the geological media around the repository. For Bench Mark Test no. 1 (BMT1) of the DECOVALEX III project, seven multinational research teams studied the implications of coupled THM processes on the safety of a hypothetical nuclear waste repository at the near-field and are presented in three accompanying papers in this issue. This paper is the first of the three companion papers, which provides the conceptualization and characterization of the BMT1 as well as some general conclusions based on the findings of the numerical studies. It also shows the process of building confidence in the mathematical models by calibration with a reference T–H–M experiment with realistic rock mass conditions and bentonite properties and measured outputs of thermal, hydraulic and mechanical variables

Numerical study of the THM effects on the near-field safety of a hypothetical nuclear waste repository—BMT1 of the DECOVALEX III project. Part 2: Effects of THM coupling in continuous and homogeneous rocks

14 pagesInternational audienceAn evaluation of the importance of the thermo-hydro-mechanical couplings (THM) on the performance assessment of a deep underground radioactive waste repository has been made as a part of the international DECOVALEX III project. It is a numerical study that simulates a generic repository configuration in the near field in a continuous and homogeneous hard rock. A periodic repository configuration comprises a single vertical borehole, containing a canister surrounded by an over-pack and a bentonite layer, and the backfilled upper portion of the gallery. The thermo-hydro-mechanical evolution of the whole configuration is simulated over a period of 100 years. The importance of the rock mass's intrinsic permeability has been investigated through scoping calculations with three values: 10−17, 10−18 and 10−19 m2. Comparison of the results predicted by fully coupled THM analysis as well as partially coupled TH, TM and HM analyses, in terms of several predefined indicators of importance for performance assessment, enables us to identify the effects of the different combinations of couplings, which play a crucial role with respect to safety issues. The results demonstrate that temperature is hardly affected by the couplings. In contrast, the influence of the couplings on the mechanical stresses is considerable

Defect-engineered metal-organic frameworks (MOF-808) towards the improved adsorptive removal of organic dyes and chromium (vi) species from water

In this work, two defective zirconium-based metal-organic frameworks (Zr-MOFs), MOF-808-OH and MOF-808-NH2, were synthesized by partially replacing the 1,3,5-benzenetricarboxylate building block with 5-hydroxyisophthalate and 5-aminoisophthalate, respectively. The structural features of the defective materials were analyzed by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), nitrogen physisorption at 77 K, and thermogravimetric analysis (TGA). Importantly, the number of defect sites determined via proton nuclear magnetic resonance (1H-NMR) analysis of the digested materials was approximately 7 mol% for MOF-808-OH and 3 mol% for MOF-808-NH2. The presence of the defect sites increased the number of acidic centers on Zr-clusters originating from missing-linker nodes which accounted for a remarkable adsorption capacity towards various anionic organic dyes and chromium (vi) species. Compared to standard MOF-808, the defect-engineered ones showed significant increments by 30-60% in trapping capacity for anionic contaminants including sunset yellow, quinoline yellow, methyl orange, and potassium dichromate, while they exhibited modest improvements by 5-15% in the removal of cationic dyes, namely malachite green and methylene blue