Research on distribution performance of desert sand for heat storage in downcomer

In this research, desert sand is used as the sensible heat storage medium, which exchanges heat with air in the downcomer to realize heat storage and heat release. The desert sand distribution uniformity has a significant impact on the heat exchange performance and efficiency between desert sand and air for the process of convection in the downcomer. Given the superiority of sensible heat storage in convective heat transfer between desert sand and air, distributors with cylinder or conical bore solid particles and homogeneity performance testing device are designed and manufactured on the basis of convection system equipped with solid particle–air downcomer. Then, the convection experiment between solid sand and air is researched. The greater the desert sand flow rate and higher the volume density, the larger the variance of regional mass flow rate and the worse the homogeneity performance. For the cylinder bore distributor, the smaller the sand particle size is, the greater affected the sand groups can be. The sand homogeneity performance is preferable with the two particle size ranges: 0.18-0.25 mm and 0.15-0.18 mm. The total sand flow rate decreases, but the uniformity improves with the increase of the air flow velocity, and the best distribution performance is achieved at an air velocity of 0.6 m/s. However, the distribution performance declines with the air flow velocity persistently increasing because the sand groups are pushed to one pipe side close to the wall. The sand groups deflect seriously with the air flow velocity increasing.     

Rabbit biocontrol and landscape‐scale recovery of threatened desert mammals

Funding for species conservation is insufficient to meet the current challenges facing global biodiversity, yet many programs use expensive single‐species recovery actions and neglect broader management that addresses threatening processes. Arid Australia has the world's worst modern mammalian extinction record, largely attributable to competition from introduced herbivores, particularly European rabbits (Oryctolagus cuniculus) and predation by feral cats (Felis catus) and foxes (Vulpes vulpes). The biological control agent rabbit hemorrhagic disease virus (RHDV) was introduced to Australia in 1995 and resulted in dramatic, widespread rabbit suppression. We compared the area of occupancy and extent of occurrence of 4 extant species of small mammals before and after RHDV outbreak, relative to rainfall, sampling effort, and rabbit and predator populations. Despite low rainfall during the first 14 years after RHDV, 2 native rodents listed by the International Union for Conservation of Nature (IUCN), the dusky hopping‐mouse (Notomys fuscus) and plains mouse (Pseudomys australis), increased their extent of occurrence by 241–365%. A threatened marsupial micropredator, the crest‐tailed mulgara (Dasycercus cristicauda), underwent a 70‐fold increase in extent of occurrence and a 20‐fold increase in area of occupancy. Both bottom‐up and top‐down trophic effects were attributed to RHDV, namely decreased competition for food resources and declines in rabbit‐dependent predators. Based on these sustained increases, these 3 previously threatened species now qualify for threat‐category downgrading on the IUCN Red List. These recoveries are on a scale rarely documented in mammals and give impetus to programs aimed at targeted use of RHDV in Australia, rather than simply employing top‐down threat‐based management of arid ecosystems. Conservation programs that take big‐picture approaches to addressing threatening processes over large spatial scales should be prioritized to maximize return from scarce conservation funding. Further, these should be coupled with long‐term ecological monitoring, a critical tool in detecting and understanding complex ecosystem change.     

Carrying capacity of an uninhabited island off the southwestern coast of Korea

An emergy evaluation was carried out to assess the carrying capacity of a small, uninhabited island (Woosedo) off the southwestern coast of Korea. The sea area within 1 km from the high tide level of the island was included in the evaluation. The total environmental emergy input to Woosedo was 1.66E19 sej/yr, with the most emergy contribution from the tidal energy. The land and marine ecosystems of Woosedo contributed 4.97 million Em$ (7600 Em$/ha/yr) to the Korean economy annually. If Woosedo was developed to the national average at the emergy investment ratio of 2.86, its carrying capacity was estimated at 1034 people at the current living standard of Korea. With this population, the island system would not be sustainable with a very low emergy sustainability index of 0.36. At the same living standard used in the developed scenario, the carrying capacity of the island would be 370 people for a sustainable development scenario and 270 people if the renewable emergy were the only source to support the population. The emergy contribution of the marine ecosystem of the island was the major source of support in determining the level of carrying capacity of the island.     

珠江三角洲区域一体化的水利政策法规体系研究

建立珠江三角洲区域一体化的水利政策法规体系是珠江三角洲国民经济社会发展和水利现代化建设的需要。从珠江三角洲地区现行水利政策法规存在的问题入手,开展珠江三角洲区域一体化的政策法规体系研究。结果表明：珠江三角洲地区现行水利政策法规体系仍很不完善,许多立、改、废工作亟待进行,2008年水政执法有效率总体较高,但很少在珠江三角洲层面开展区域一体化的联合执法,珠江三角洲水利政策法规体系建设应重点加强与水利现代化建设、水资源一体化配置、保护及管理相关的政策法规,进而建立统一协调、快速高效的区域一体化的联合执法体系。     

Impacts of the deforestation driven by agribusiness on urban population and economic activity in the Dry Chaco of Argentina

Agriculture expansion oriented to global market has changed the relation between population and deforestation in South America. Actually, the population dynamic in an agricultural frontier turned into a consequence of deforestation (rather than the cause). For Dry Chaco of Argentina during the period 1991–2001, we explore the impacts of deforestation over urban population and employment dynamics in small- and medium-size urban centers. We used deforestation maps from remote sensing data and demographic information from the national census. We found a positive relation between population growth and deforestation. Additionally, urban centers in a context of new and active deforestation stages generate more jobs than in a context of advanced stages. Based on our results, we suggest a boom and bust pattern. Agriculture expansion and deforestation generate transient jobs and benefits, but in a long-run perspective, positive impacts are uncertain.     

三维荧光光谱结合荧光区域指数分析方法评估堆肥腐熟度

评估堆肥腐熟度是确保堆肥产品质量的重要保证. 采用三维荧光光谱结合荧光区域指数分析方法快速评估菜粕和稻糠堆肥过程中的腐熟度. 结果表明:菜粕和稻糠堆肥可在16 d内完成一次发酵,其中第7～14天为高温期(>50 ℃,共8 d);随后,堆体进入降温期,第16天降至32 ℃. 堆肥初期(第0～6天)DOC(溶解性有机碳)、DON(溶解性有机氮)质量浓度和EC(电导率)先稳定在一个较低的水平;在堆肥高温期(第7～14天),ρ(DOC)、 ρ(DON)和EC则分别迅速升至10.47 mg/L、7.52 mg/L和5.76 mS/cm. 堆肥腐熟度相关指标〔即ρ(DOC)、 ρ(DON)和EC〕与FRI(荧光区域指数)方法中P_Ⅲ,n、P_Ⅴ,n、P_Ⅴ,n/P_Ⅲ,n指标的变化趋势一致,并且具有极显著相关性(R>0.942,P<0.01);而与P_Ⅰ,n变化趋势相反,也具有显著的相关性(R<-0.871,P<0.05). 因此,P_Ⅲ,n、P_Ⅴ,n、P_Ⅴ,n/P_Ⅲ,n与P_Ⅰ,n可以用于表征堆肥腐熟度.      

区域生态学基本理论探索

全球经济一体化、区域发展一体化,以及生态服务转移引发的区域生态问题越来越受到人们的关注,区域生态问题也直接影响到区域的可持续发展.因此,构建一门针对区域生态问题的系统学科成为当务之急.本文基于生态学、地理学、经济学及其它相关学科理论,尝试从学科发展角度探讨建立区域生态学学科理论框架.文章提出区域生态学是研究区域生态结构、过程、功能,以及区域间生态要素耦合和相互作用机理的学科,生态介质是区域生态的联系纽带和核心要素.根据生态系统构成要素和当前人类活动,影响区域的突出生态介质有水、风和资源,通过这3种介质,分别形成流域、风域和资源圈3大类型生态区域.区域生态学的主要研究范畴和要点有：区域生态结构、过程与功能、区域生态完整性和生态分异规律、区域生态演变规律及其驱动力、区域生态承载力和生态适宜性、区域生态联系和生态资产流转,以及区域生态补偿和环境利益共享机制.     

不同排污收费情景下的发电企业减排模型研究

考虑未来多种污染物排污收费情景及区域电力需求的固有随机特性,建立了2阶段电源规划优化模型,分析了不同排污收费情景、不同电力需求水平下的区域电力结构变化以及污染物和CO2减排策略.在同时征收SO2排污费和CO2排放费的情景(情景3)下,清洁能源发电在发电系统中的比重增加,以煤电为主的火电比重下降;系统减排CO2 8.438′106t,同时协同减排SO2 5202t、NOx 7854t、颗粒物17.42t,但系统费用会显著增加.在同时征收SO2、NOx排污费和CO2排放费的情景下,系统减排SO2 8515t、NOx 13878t、颗粒物23.52t、CO2 12.988′106t,同时系统费用也会进一步增加.在目前征收SO2排污费的基础上征收CO2排放费或同时征收NOx排放费和CO2排放费,可以提高清洁发电方式在发电系统中的比重,降低SO2、NOx和CO2的排放量.     

基于AERMOD及减排政策的昆明市工业区SO2情景模拟

以昆明市工业区为试点,将2009年作为基准年,2015年作为情景年,利用Aermod模型系统以及相关数据对工业区内SO2环境浓度进行预测.模拟情景的建立基于“十二五”工业源减排规划.研究发现工业源减排措施将对区域SO2浓度有显著影响,降幅最高可达13%.2015年不同模拟时段的SO2等浓度下分布面积均较2009年有明显减小,高浓度地区个数变少,这种现象也出现在污染源非集中地区.研究结果表明利用模型预测可有效分析减排政策对工业区内环境质量状况的影响,有助于建立减排响应机制.     

秸秆还田对江西农田土壤固碳影响的模拟分析

秸秆还田等农田管理措施能有效地增加土壤碳储量,从而有利于减缓大气CO₂浓度的上升趋势。论文基于环境政策综合气候模型(EPIC),采用千烟洲生态试验站和鹰潭生态试验站农田监测场长期观测数据,验证和优化了EPIC模型参数,同时利用1990-2010年江西省气象资料以及土壤清查资料,模拟分析了4种秸秆还田(CR)比例情景下2010-2030年江西省水稻田土壤的固碳潜力。研究结果表明,无秸秆还田 (CR0%)和秸秆还田25%(CR25%)两种处理下耕作层土壤有机碳储量分别下降21.3%和6.5%,秸秆还田50%(CR50%)和100%(CR100%)处理下土壤有机碳储量分别增加5.4%和11.9%;相对CR0%情景而言,CR25%、CR50%、CR100% 情景下江西省水稻田土壤总固碳潜力分别为6.43、14.92和25.26 TgC(1 Tg = 10⁶ t)。研究结果表明,通过合理的调控措施,采用保护性耕作(秸秆还田)是提高水稻田土壤固碳能力的一种有效途径。