粤北山区生态旅游发展的战略思路及对策研究

粤北山区山清水秀,生态优良,民俗风情浓郁,客家文化底蕴深厚,具有发展生态旅游的优势条件.在分析生态旅游开发环境和资源条件的基础上,对粤北山区生态旅游发展的战略思路和战略定位进行了深入探讨,提出构建区域性旅游中心城市、塑造系列特色生态文化旅游精品、打造客家文化生态旅游区和加强区域旅游合作的建议,以期实现粤北山区旅游可持续发展.     

引入化学反应的600MW火电机组烟气SCR脱硝性能模拟

以600 MW火电机组现有SCR脱硝装置为研究对象,应用CFD软件完成建立模型、划分网格、选择数学模型、设置边界条件、模拟计算等工作,最终得出SCR脱硝系统流速分布及Cv值、压力损失、NH3分布及逃逸浓度等结果。结果表明:SCR脱硝系统流速分布均匀、偏差符合设计要求,NH3与烟气混合均匀,氨逃逸浓度低。     

Preparation of Calcium Silicate Absorbent from Iron Blast Furnace Slag

ABSTRACT

Calcium silicate hydrate (CSH) solids were prepared from hydrated lime and iron blast furnace slag in an aqueous agitated slurry at 92 °C. While it was hoped a minimal lime/slag ratio could be used to create near-amorphous CSH, the surface area of the product improved by increasing the lime/slag weight ratio to 2. The addition of gypsum to the lime/slag system dramatically improved the formation of surface area, creating solids with 139 m²/g after 30 hr of reaction when only a minimal amount of lime was present. The SO₂ reactivity of solids prepared with gypsum greatly exceeded that of hydrated lime, achieving greater than 70-80% conversion of the alkalinity after 1 hr of reaction with SO₂. The use of CaCl₂ as an additive to the lime/slag system, in lieu of gypsum, also produced high-surface-area solids, 115 m²/g after 21 hr of reaction. However, the SO₂ reactivity of these sorbents was relatively low given the high surface area. This emphasized that the correlation between surface area and SO₂ reactivity was highly dependent on the solid phase, which was subsequently dependent on slurry composition.     

Nitrogen footprints: Regional realities and options to reduce nitrogen loss to the environment

Ambio - Nitrogen (N) management presents a sustainability dilemma: N is strongly linked to energy and food production, but excess reactive N causes environmental pollution. The N footprint is an...     

An introduction to decision science for conservation

Biodiversity conservation decisions are difficult, especially when they involve differing values, complex multidimensional objectives, scarce resources, urgency, and considerable uncertainty. Decision science embodies a theory about how to make difficult decisions and an extensive array of frameworks and tools that make that theory practical. We sought to improve conceptual clarity and practical application of decision science to help decision makers apply decision science to conservation problems. We addressed barriers to the uptake of decision science, including a lack of training and awareness of decision science; confusion over common terminology and which tools and frameworks to apply; and the mistaken impression that applying decision science must be time consuming, expensive, and complex. To aid in navigating the extensive and disparate decision science literature, we clarify meaning of common terms: decision science, decision theory, decision analysis, structured decision-making, and decision-support tools. Applying decision science does not have to be complex or time consuming; rather, it begins with knowing how to think through the components of a decision utilizing decision analysis (i.e., define the problem, elicit objectives, develop alternatives, estimate consequences, and perform trade-offs). This is best achieved by applying a rapid-prototyping approach. At each step, decision-support tools can provide additional insight and clarity, whereas decision-support frameworks (e.g., priority threat management and systematic conservation planning) can aid navigation of multiple steps of a decision analysis for particular contexts. We summarize key decision-support frameworks and tools and describe to which step of a decision analysis, and to which contexts, each is most useful to apply. Our introduction to decision science will aid in contextualizing current approaches and new developments, and help decision makers begin to apply decision science to conservation problems.     

On the risk of extinction of a wild plant species through spillover of a biological control agent: Analysis of an ecosystem compartment model

Invasive plant species can be controlled by introducing natural enemies (insect herbivores) from their native range. However, such introduction entails the risk that the introduced herbivores attack indigenous plant species in the area of introduction. Here, we study the effect of spillover of a herbivore from a managed ecosystem compartment (agriculture) to a natural compartment (non-managed) and vice versa. In the natural compartment, an indigenous plant species is attacked by the introduced herbivores, whereas another indigenous plant species, which competes with the first, is not attacked. The combination of competition and herbivory may result in extinction of the attacked wild plant species. Using a modelling approach, we determine model parameters that characterize the risk of extinction for a wild plant species. Risk factors include: (1) a high attack rate of the herbivores on the wild non-target species, (2) niche overlap expressed as strong competition between the attacked non-target species and its competitor(s), and (3) factors favouring large spillover from the managed ecosystem compartment to the natural compartment; these include (3a) a high dispersal ability, and (3b) a moderate attack rate of the introduced herbivore on the target species, enabling large resident populations of the insect herbivore in the managed compartment. The analysis thus indicates that a high attack rate on the target species, which is a selection criterion for biocontrol agents with respect to their effectiveness, also mitigates risks resulting from spillover and non-target effects. While total eradication of an invasive plant species is not possible in the one-compartment-one-plant-one-herbivore system, natural enemy spillover from a natural to a managed compartment can make the invasive weed go extinct.     

Impacts of national park tourism sites: a perceptual analysis from residents of three spatial levels of local communities in Banff national park

Environment, Development and Sustainability - Communities next to national parks, known as gateway communities, can benefit from national park development. Gateway communities are unique and...