我国乡村旅游文献研究的特点与评价

我国乡村旅游发展历史较短，相关的研究文献集中出现在20世纪90年代末期及以后，乡村旅游研究文献的深度和广度一定程度上凸显了我国乡村旅游发展和研究现状。选取具有代表性的89篇乡村旅游文献，在全面分析文献内容的基础上，从不同的角度进行数理统计分析，得出国内乡村旅游文献研究的一些特点，同时做出相应的评价和展望。     

Merits of ozonation and catalytic ozonation pre-treatment in the algal treatment of pulp and paper mill effluents

Since the performance of algal treatment for pulp mill effluent decreases with increasing color intensity and AOX content, which mainly originate from the chlorine bleaching of Kraft pulp, the separated CEH bleaching effluent was pre-treated by both the conventional and the heterogeneous catalytic ozonation processes. An increase in the BOD(5)/COD ratio from 0.11 to 0.28 and 87% color abatement in terms of Pt-Co were achieved by catalytic ozonation, which had the best treatment performance. Biodegradability enhancement of the CEH effluent correlated well with a decrease in toxicity, high-molecular-weight-compound content, and AOX abatement. By the pre-treatment of the CEH bleaching effluent, the overall efficiencies of algal treatment of the combined pulp mill effluent in terms of the fractional removal of COD and color were increased from 76% and 53% to 86-90% and 96-99%, respectively. Effects of both the conventional and the catalytic ozonation pre-treatments on subsequent biological treatment were close to each other and they reduced the filling period of the Sequential Batch Reactor (SBR) cycle from 8 to 5 days.     

Effect of sequentially combining methanol and acetic acid on the performance of biological nitrogen and phosphorus removal

A sequentially combined carbon (SCC) source using methanol and acetic acid was investigated for biological nitrogen and phosphorus removal in a wastewater treatment process consisting of an anoxic zone, an oxic zone and a final settling tank. The anoxic zone was divided into two separate anoxic zones to feed methanol in the first anoxic zone and acetic acid in the second anoxic zone. Methanol and acetic acid, each as the sole carbon source, were also tested for comparison. The use of SCC was superior in nitrogen removal with all combined COD ratios of methanol/acetic acid tested, yielding 95.8-97% efficiency (less than 1 mg N/l in the final effluent). The highest phosphorus removal of above 92% (final effluent concentration of 0.12 mg P/l) was achieved when only acetic acid was used at a quantity equivalent to 50 mg COD/l. However, when SCC was used, the acetic acid dosage of 50 mg COD/l could be reduced down to 20 mg COD/l when 30 mg COD/l was replaced by methanol; this resulted in a final effluent phosphorus concentration of 0.6 mg P/l. Additional benefits of SCC included the excellent sludge settling properties compared to the use of methanol or acetic acid alone.     

Influence of parameters on the heterogeneous photocatalytic degradation of pesticides and phenolic contaminants in wastewater: a short review

In recent years, the application of heterogeneous photocatalytic water purification processes has gained wide attention due to its effectiveness in degrading and mineralizing the recalcitrant organic compounds as well as the possibility of utilizing the solar UV and visible-light spectrum. This paper aims to review and summarize the recent works on the titanium dioxide (TiO(2)) photocatalytic oxidation of pesticides and phenolic compounds, predominant in storm and wastewater effluents. The effects of various operating parameters on the photocatalytic degradation of pesticides and phenols are discussed. Results reported here suggest that the photocatalytic degradation of organic compounds depends on the type and composition of the photocatalyst and, light intensity, initial substrate concentration, amount of catalyst, pH of the reaction medium, ionic components in water, solvent types, oxidizing agents/electron acceptors, catalyst application mode, and calcination temperature in the water environment. A substantial amount of research has focused on the enhancement of TiO(2) photocatalysis by modification with metal, non-metal and ion doping. Recent developments in TiO(2) photocatalysis for the degradation of various pesticides and phenols are also highlighted in this review. It is evident from the literature survey that photocatalysis has good potential to remove a variety of organic pollutants. However, there is still a need to determine the practical utility of this technique on a commercial scale.     

Multi-scale analysis of a household level agent-based model of landcover change

Scale issues have significant implications for the analysis of social and biophysical processes in complex systems. These same scale implications are likewise considerations for the design and application of models of landcover change. Scale issues have wide-ranging effects from the representativeness of data used to validate models to aggregation errors introduced in the model structure. This paper presents an analysis of how scale issues affect an agent-based model (ABM) of landcover change developed for a research area in the Midwest, USA. The research presented here explores how scale factors affect the design and application of agent-based landcover change models. The ABM is composed of a series of heterogeneous agents who make landuse decisions on a portfolio of cells in a raster-based programming environment. The model is calibrated using measures of fit derived from both spatial composition and spatial pattern metrics from multi-temporal landcover data interpreted from historical aerial photography. A model calibration process is used to find a best-fit set of parameter weights assigned to agents' preferences for different landuses (agriculture, pasture, timber production, and non-harvested forest). Previous research using this model has shown how a heterogeneous set of agents with differing preferences for a portfolio of landuses produces the best fit to landcover changes observed in the study area. The scale dependence of the model is explored by varying the resolution of the input data used to calibrate the model (observed landcover), ancillary datasets that affect land suitability (topography), and the resolution of the model landscape on which agents make decisions. To explore the impact of these scale relationships the model is run with input datasets constructed at the following spatial resolutions: 60, 90, 120, 150, 240, 300 and 480 m. The results show that the distribution of landuse-preference weights differs as a function of scale. In addition, with the gradient descent model fitting method used in this analysis the model was not able to converge to an acceptable fit at the 300 and 480 m spatial resolutions. This is a product of the ratio of the input cell resolution to the average parcel size in the landscape. This paper uses these findings to identify scale considerations in the design, development, validation and application of ABMs of landcover change.     

Anaerobic-aerobic treatment of purified terephthalic acid (PTA) effluent; a techno-economic alternative to two-stage aerobic process

This paper addresses the treatment of purified terephthalic acid (PTA) effluent using anaerobic and aerobic processes. Laboratory studies were carried out on flow proportionate composite wastewater generated from the manufacturing of PTA. An activated sludge process (ASP-two stage and single stage) and an upflow anaerobic fixed film fixed bed reactor (AFFFBR) were used, individually and in combination. The performance of a full-scale ETP under existing operating conditions was also studied. Full scale ETP studies revealed that the treatment of PTA effluent using a two-stage ASP alone does not meet treated effluent quality within the prescribed Indian Standards. The biomass produced in the two stage ASP was very viscous and fluffy and the sludge volume index (SVI) was very high (200-450 ml/g). However, pretreatment of PTA effluent using an upflow AFFFBR ensured substantial reduction in BOD (63%) and COD (62%) with recovery of biogas at 1.8-1.96 l/l effluent treated at a volumetric loading rate (VLR) 4-5 kg COD/m(3) d. The methane content in the biogas varied between 55% and 60%. The pretreated effluent from the upflow AFFFBR was then treated through a single stage ASP. The biomass produced in the ASP after anaerobic treatment had very good settlability (SVI: 75-90 ml/g) as compared to the two stage ASP and the treated effluent quality with respect to BOD, COD and SS was within the prescribed Indian Standards. The alternative treatment process comprising an upflow AFFFBR and a single stage ASP ensured net power saving of 257 kW and in addition generated 442 kW of power through the AFFFBR.     

“文化旅游圈”视角下的古都旅游开发——以开封为例

国内旅游开发趋近成熟,规模效应初显,旅游目的地竞争也应适时调整策略.整合资源、抱团竞争成为区域旅游增强竞争力的重要手段.开封作为“七朝古都”,拥有丰富的文化旅游资源,尤其是北宋遗留的历史胜迹非常丰富.在相关研究的基础上,选取开封“宋文化”主题为切入点,以区域旅游整合开发为指导理念,提出文化旅游圈的构想,论述了“宋文化”旅游圈的功能与构建对策,以期为构建此文化旅游圈提出可行性建议.     

柠檬酸废水处理改造工程实例

采用多级内循环厌氧反应器MIC/上升式厌氧反应器UASB串联工艺处理柠檬酸生产排放的高浓度有机废水,其中厌氧处理段的COD去除率＞94％,整体COD去除率可达98.3％左右.最终排放口出水COD平均值为190 mg/L,pH值为6～9,达到柠檬酸行业废水排放标准.     

Multimodel inference and adaptive management

Ecology is an inherently complex science coping with correlated variables, nonlinear interactions and multiple scales of pattern and process, making it difficult for experiments to result in clear, strong inference. Natural resource managers, policy makers, and stakeholders rely on science to provide timely and accurate management recommendations. However, the time necessary to untangle the complexities of interactions within ecosystems is often far greater than the time available to make management decisions. One method of coping with this problem is multimodel inference. Multimodel inference assesses uncertainty by calculating likelihoods among multiple competing hypotheses, but multimodel inference results are often equivocal. Despite this, there may be pressure for ecologists to provide management recommendations regardless of the strength of their study's inference. We reviewed papers in the Journal of Wildlife Management (JWM) and the journal Conservation Biology (CB) to quantify the prevalence of multimodel inference approaches, the resulting inference (weak versus strong), and how authors dealt with the uncertainty. Thirty-eight percent and 14%, respectively, of articles in the JWM and CB used multimodel inference approaches. Strong inference was rarely observed, with only 7% of JWM and 20% of CB articles resulting in strong inference. We found the majority of weak inference papers in both journals (59%) gave specific management recommendations. Model selection uncertainty was ignored in most recommendations for management. We suggest that adaptive management is an ideal method to resolve uncertainty when research results in weak inference.     

Environmental education research notes (USA)

Conclusion The Commission's efforts are currently in a second phase directed toward identification and additional of more research papers and higher levels of analysis. Funding support is provided from the operating budget of the National Association for Environmental Education. Persons interested in additional information concerning the activities of the NCEER may contact Professor Iozzi at The Institute for Science, Technology, and Social Science Education, Rutgers—The State University of New Jersey, Doolittle Hall, New Brunswick, NJ 08903 USA. Copies ofResearch in Environmental Education 1971–1980 may be obtained from the publisher, SMEAC Information Reference Center, The Ohio State University, 1200 Chambers Road, Columbus, OH 43212 USA, for $15. also Associate Director, Educational Resources Information Center (ERIC) Clearinghouse for Science, Mathematics, and Environmental Education (SMEAC). In preparing these notes, use was made of abstracts printed inResearch in Environmental Education 1971–1980.     

Household use of and satisfaction with alternative water sources in Victoria Australia

Climate change is increasing the variability of rainfall, and thus the availability of water supplies in many areas of the world. These impacts are already being felt in the state of Victoria, Australia where a 12 year drought period was recently experienced. Restrictions to water use have been implemented, as one component of a broad policy approach to manage the drought. While anecdotal evidence suggests that the substitution of centralised water supplies is occurring, this has not been proven empirically. This paper reports results from a survey of households in Victoria regarding their use of alternative water sources. The study found that substitution is occurring. Garden watering is the purpose which has the highest rate of alternative water source use. In total 41.6% of respondents always, and 33.2% sometimes use an alternative water source for garden watering. The most commonly used alternative source of water for garden watering is water previously used in the laundry (30.7%). The alternative source of water used was found to vary depending on the purpose of the water use. High levels of satisfaction were found for all alternative water sources used. Several barriers were found to the use of alternative water sources, the main of which were: inflexibility of existing infrastructure, cost, policy, and housing status. The results have implications for water retailers, policy makers and governments in locations facing water shortage.     

湿式空气非均相催化氧化处理有机废水中难降解有机物的研究

湿式空气催化氧化是曩为经济的环境友好型高级氧化技术之一,在处理有机废水中难降解有机物方面极具前景.为提高氧化效率,钌（Ru）、铑（Rh）、铂（Pt）、钯（Pd）等贵金属及铜（Cu）、铈（Ce）、锰（Mn）、铁（Fe）、镍（Ni）、铝（Al）、铬（Cr）及钴（Co）等金属氧化物等常作为非均相催化剂应用到湿式空气催化氧化体系中.本文对非均相催化湿式空气氧化处理有机废水中难降解有机物的非均相催化剂、工艺条件及反应机理进行了探讨,最后指出了催化剂的失效、解决方法及技术发展方向.     

Occurrence of carbamazepine in soils under different land uses receiving wastewater

Due to its resistance to many wastewater treatment processes, the antiepileptic drug carbamazepine (CBZ) is routinely found in wastewater effluent. Wastewater irrigation is an alternative to stream discharge of wastewater effluent, which utilizes the soil as a tertiary filter to remove excess nutrients and has the potential to remove pharmaceutical compounds. Previous data suggest that CBZ is strongly sorbed to soil; however, it is unknown what its fate is for long periods of irrigation and if land use affects its distribution. Therefore, the objectives of our research were to characterize CBZ concentrations in soils that have been receiving wastewater irrigation for >25 yr under three different land uses: cropped, grassed, and forested. Triplicate soil cores were collected at each of the land uses to a depth of 120 cm. Extractions for CBZ were performed using 5-g soil samples and 20 mL of acetonitrile. The extracted solutions were analyzed on a liquid chromatograph tandem mass spectrometer. The samples were also analyzed for supporting information such as organic carbon, pH, and electrical conductivity. Results suggest that there is accumulation of the CBZ in the surface soils, which have the highest organic carbon content. Average concentrations of CBZ in the surface soils were 4.92, 2.9, and 1.92 ng g, for the forested, grassed, and cropped land uses, respectively. The majority of the CBZ was found in the upper 30 cm of the profile. Our results suggest that the soils adsorb CBZ and slow its movement into groundwater, compared to the movement of nonadsorbed chemicals.     

POTENTIAL EFFECTS OF CLIMATE CHANGE ON AGRICULTURAL WATER USE IN THE SOUTHEAST U.S.1

ABSTRACT: Climate change has the potential to have dramatic effects on the agricultural sector nationally and internationally as documented in many research papers. This paper reports on research that was focused on a specific crop growing area to demonstrate how farm managers might respond to climate-induced yield changes and the implications of these responses for agricultural water use. The Hadley model was used to generate climate scenarios for important agricultural areas of Georgia in 2030 and 2090. Linked crop response models indicated generally positive yield changes, as increased temperatures were associated with increased precipitation and CO2. Using a farm management model, differences in climate-induced yield impacts among crops led to changes in crop mix and associated water use; non-irrigated cropland received greater benefit since irrigated land was already receiving adequate moisture. Model results suggest that farm managers will increase cropping intensity by decreasing fallowing and increasing double cropping; corn acreage decreased dramatically, peanuts decreased moderately and cotton and winter wheat increased. Water use on currently irrigated cropland fell. The potential for increased water use through conversion of agriculturally important, but currently non-irrigated, growing areas is substantial.     

A TWO-DIMENSIONAL PARTICLE TRACKING ESTUARINE TRANSPORT MODEL1

ABSTRACT: A two-dimensional particle tracking model is developed for estuarine water quality investigation. The method requires only the solution of a two-dimensional hydrodynamics model and, therefore, is more economical to use than conventional multi-dimensional estuarine transport models. The present model does not consider turbulent diffusion, and it handles only conservative constituents. The model was applied to Humboldt Bay, California, where the flushing of sewage effluent was simulated. The model was applied to evaluate the present release plan, and to determine alternative release plans for limiting the transport of sewage effluent into shellfish producing areas Within the Bay.     

Nitrous oxide emissions from wastewater treatment and water reclamation plants in southern California

Nitrous oxide (N?O) is a long-lived and potent greenhouse gas produced during microbial nitrification and denitrification. In developed countries, centralized water reclamation plants often use these processes for N removal before effluent is used for irrigation or discharged to surface water, thus making this treatment a potentially large source of N?O in urban areas. In the arid but densely populated southwestern United States, water reclamation for irrigation is an important alternative to long-distance water importation. We measured N?O concentrations and fluxes from several wastewater treatment processes in urban southern California. We found that N removal during water reclamation may lead to in situ N?O emission rates that are three or more times greater than traditional treatment processes (C oxidation only). In the water reclamation plants tested, N?O production was a greater percentage of total N removed (1.2%) than traditional treatment processes (C oxidation only) (0.4%). We also measured stable isotope ratios (δN and δO) of emitted N?O and found distinct δN signatures of N?O from denitrification (0.0 ± 4.0 ‰) and nitrification reactors (-24.5 ± 2.2 ‰), respectively. These isotope data confirm that both nitrification and denitrification contribute to N?O emissions within the same treatment plant. Our estimates indicate that N?O emissions from biological N removal for water reclamation may be several orders of magnitude greater than N?O emissions from agricultural activities in highly urbanized southern California. Our results suggest that wastewater treatment that includes biological nitrogen removal can significantly increase urban N?O emissions.     

Local Sustainability Indicators

Local Environment has established a bit of a niche in local sustainability indicator studies. In 1997 it published the important debate between Jeb Brugman and Graham Pinfield, which highlighted that sustainability indicators and their role are contested issues (Vol. 2, Nos 1-3). In 1999 it produce a first special issue on the topic (Vol. 4, No. 2). As the editors identified, this special issue probed ‘deeper into aspects of indicator selection, methodology, theory and practice’. The papers presented there began to discuss a theme that is developed further in this special issue, that of the relationship between the objective and the subjective in indicator development and use. Our special issue brings together three full papers and a commentary presenting research and information from the USA, Sweden, France and Austria. In this editorial we are going to review the growth of interest in sustainability indicators and the changing way in which they are viewed and briefly comment on some recent indicator projects that we have been involved in.     

国内外旅游网络平台研究进展与基金项目资助

通过对国内外1979—2019年的831篇文献进行梳理、归纳与总结,从年度载文数量、来源期刊类型、作者发文篇数等6个方面入手,分析比较了国内外旅游网络平台的研究现状、研究热点及进展,研究依次分为起步阶段、拓展阶段与提升阶段。结果表明:①国外对旅游网络平台的研究已进入提升阶段,国内正处于拓展阶段。②国内外均采用定性与定量相结合的研究方法,国内定量的数学模型相对简单,国外定量的数学模型相对复杂。③国内外“以人为本”为切入点研究旅游活动主体——旅游者的需求,国内侧重旅游网络平台的设计和营销及实例等,国外侧重研究个性化定制的旅游网络平台。通过对国内外基金项目资助的发文量分析,展望了国内外旅游网络平台发展的新动态。     

植物修复研究的知识谱图分析

为了解有关植物修复研究领域的研究热点、发展趋势、核心作者及研究机构,通过检索1999~2020(3.18)年共21年CNKI数据库中有关植物修复研究的文献,利用CiteSpace软件绘制关于植物修复研究的知识谱图,并进行文献可视化分析。结果表明:近21年来该研究领域发文数量呈波动式增长态势;我国植物修复研究近年来主要分布在重金属污染修复领域,以重金属污染、土壤、黑麦草、生态修复、超富集植物等为主要关键词;骆永明、吴龙华、周启星、陈同斌、林立金、王丹等是主要发文作者;我国植物修复研究近年来呈局部集中,总体分散的特征,主要研究机构为西南科技大学生命科学与工程学院、中国科学院大学/中国科学院研究生院、中国科学院南京土壤研究所等;我国植物修复研究自1999年开始,1999~2003年为起步初探阶段,2004~2015年为稳定发展阶段,2016~2020(3.18)为快速增长阶段。研究为我国未来植物修复研究提供了一定的借鉴和指导。