Analysis of water temperatures in Conowingo Pond as influenced by the Peach Bottom atomic power plant thermal discharge

Numerical surface water hydrodynamic and transport models have been traditionally applied to predict power plant thermal impacts under design conditions. The need to understand both thermal impacts and receiving water biogeochemical impacts and associated ecological and health risks under highly variable transient conditions on seasonal to annual time scales necessitates the use of predictive multidimensional modeling systems. Over the last decade, three-dimensional hydrodynamic and reactive transport modeling has matured from a research subject to a practical analysis technology. Simultaneously, computational requirements for realistic three-dimensional modeling have changed from super computers and high-end workstations to economical commodity personal computers. This paper describes a three-dimensional surface water model system, the Environmental Fluids Dynamics Code (EFDC), capable of addressing a variety of power plant impact issues, including thermal transport, water quality-eutrophication, and toxic contaminant transport and fate, in surface water systems. The development history of the model and its previous applications, as well as its theoretical and computational formulations are presented. Model extensions addressing coupled near- and far-field thermal transport due to high velocity cooling water discharges are discussed in detail. To illustrate the model’s capabilities, preliminary results of thermal transport in Conowingo Pond associated with the Peach Bottom Atomic Power Station’s (PBAPSs) discharge are presented and compared with field observations.     

Parallel processing of a random-walk model of atmospheric dispersion

Algorithms for random-walk models of atmospheric dispersion take considerable processing time on sequential computers. Such algorithms are, however, more suited to parallel computers as they contain a high degree of parallelism. In this paper, to show this suitability and to investigate the improvement in the processing time with the use of a parallel computer, the model algorithm developed and applied in Luhar and Britter (1989, Atmospheric Environment23, 1911–1924) has been implemented on a Distributed Array of Processors (DAP). The results show a 14-fold improvement in the processing time over a sequential machine.     

Review of post-combustion carbon dioxide capture technologies using activated carbon

Carbon dioxide(CO_2) is the largest anthropogenic greenhouse gas(GHG) on the planet contributing to the global warming. Currently, there are three capture technologies of trapping CO_2 from the flue gas and they are pre-combustion, post-combustion and oxy-fuel combustion. Among these, the post-combustion is widely popular as it can be retrofitted for a short to medium term without encountering any significant technology risks or changes.Activated carbon is widely used as a universal separation medium with series of advantages compared to the first generation capture processes based on amine-based scrubbing which are inherently energy intensive. The goal of this review is to elucidate the three CO_2 capture technologies with a focus on the use of activated carbon(AC) as an adsorbent for post-combustion anthropogenic CO_2 flue gas capture prior to emission to atmosphere. Furthermore, this coherent review summarizes the recent ongoing research on the preparation of activated carbon from various sources to provide a profound understanding on the current progress to highlight the challenges of the CO_2 mitigation efforts along with the mathematical modeling of CO_2 capture. AC is widely seen as a universal adsorbent due to its unique properties such as high surface area and porous texture. Other applications of AC in the removal of contaminants from flue gas, heavy metal and organic compounds, as a catalyst and catalyst support and in the electronics and electroplating industry are also discussed in this study.     

Computational fluid dynamics applied to water and wastewater treatment facility modeling

The major issues in water and wastewater industry are to meet quality requirements, to guarantee treatment process efficiency, to contain investment and operating costs. This implies the use of powerful predictive modeling and simulation tools which are able to account for the multiple interaction between all the water quality and process design parameters. Computational Fluid Dynamics modeling tools have already been widely used in other industries but their application in water industry is quite recent. This paper presents different applications of CFD modeling to the study of the hydrodynamic and mass transfer performance of single- or two-phase flow reactors used in water and wastewater treatment. Numerical simulations, together with experimental measurements, have been performed on laboratory and full-scale plants in order to gain a better understanding of the physical phenomena (mixing, interfacial transfer) occurring in these systems. Numerical simulations are systematically validated by experiments. The paper shows how CFD can be helpful in order to improve the design of existing water treatment plants and the process efficiency. In this scope, CFD enables designs more reliable and cost effective water treatment processes which remain basic environmental policy issues.     

国际土地利用/覆盖变化模型研究综述

国际上对土地利用/覆盖变化的研究由来已久,近年由于土地利用/覆盖变化对全球变化的贡献及响应,预测土地利用/覆盖变化成为必然。由此,越来越多的科学家致力于研究土地利用/覆盖变化模型,并取得了积极进展。论文介绍了目前国际上土地利用/覆盖变化模型的一些相关问题:①土地利用/覆盖变化模拟的尺度依赖性;②土地利用/覆盖变化模拟的数据问题;③预测土地利用/覆盖变化的位置与数量。回顾了已有的5种主要的土地利用/覆盖变化模型:①基于行为者的土地利用/覆盖变化模型;②经验统计模型;③最优化模型;④混合/综合模型;⑤动力模拟模型。最后总结了现有模型中存在的问题,并探讨了今后土地利用/覆盖变化模型发展的方向。     

Computational fluid dynamics applied to water and wastewater treatment facility modeling

The major issues in water and wastewater industry are to meet quality requirements, to guarantee treatment process efficiency, to contain investment and operating costs. This implies the use of powerful predictive modeling and simulation tools which are able to account for the multiple interaction between all the water quality and process design parameters. Computational Fluid Dynamics modeling tools have already been widely used in other industries but their application in water industry is quite recent. This paper presents different applications of CFD modeling to the study of the hydro-dynamic and mass transfer performance of single- or two-phase flow reactors used in water and wastewater treatment. Numerical simulations, together with experimental measurements, have been performed on laboratory and full-scale plants in order to gain a better under-standing of the physical phenomena (mixing, interfacial transfer) occurring in these systems. Numerical simulations are systematically validated by experiments. The paper shows how CFD can be helpful in order to improve the design of existing water treatment plants and the process efficiency. In this scope, CFD enables designs more reliable and cost effective water treatment processes which remain basic environmental policy issues.     

Using structural equation modeling to test environmental performance in small and medium-sized manufacturers: can SEM help SMEs?

Small and medium-sized enterprises (SMEs), defined as manufacturers employing 500 or fewer people, represent an estimated 70–98% of the manufacturing population globally and together have the potential to significantly impact the environment. Many of these small manufacturers throughout the world are not in compliance with environmental regulations, and even fewer see the need to focus on pollution prevention, implement environmental management systems, or to use life-cycle management or other proactive environmental management practices. A validated environmental performance model for SMEs holds the promise of providing a roadmap to more productive environmental results. This paper discusses structural equation modeling as a useful methodology to validate environmental performance models.The paper shares some insights from the use of structural equation modeling, which was used to evaluate the development of an environmental performance model for SMEs. The model was based on the Malcolm Baldrige Criteria. We review SEM methodology and share results from a population of SMEs in the plastics manufacturing sector. Fit statistics confirmed the overall model fit, but not all of the paths in the model were statistically significant. An assessment of the non-significant paths (from leadership and from the system components of the model to environmental results) led the authors to conclude that an improved definition of environmental results is critical. Education of SMEs on the benefits of improved environmental performance is also warranted.     

Multi-Agent System 模型在土地利用/覆盖变化中的研究进展

在微观与中宏观尺度上,MAS模型可以反映景观中具有自动性、异质性和分散性的人类决策,利于阐明智能体对自然与社会经济环境的适应机制。因而在自然资源管理、农业经济和城市模拟等领域得到广泛应用。目前,该模型的研究主要集中在智能体决策、智能体相互作用、模型多尺度、模型检验与验证等几个方面。综合分析得出如下结论:①智能体决策框架还需进一步完善,特别有限理性决策框架(Bounded Rationality)还需进一步完善;②智能体之间相互作用的研究仍停留在定性的、概念性的水平,还需进一步研究定量分析智能体相互作用的方法;③在多尺度研究中,第一种尺度转化途径机理明确,但决策的空间显性(spatially-explicit)表达较为困难;第二种途径可以表达空间显性,但决策与土地利用变化之间的逻辑解释不强;第三种途径可以表达土地利用过程中决策与复杂性关系,但智能体之间的相互作用处理较为简单;④还需加强对模型的检验与验证方面的研究,探索验证人类复杂行为的技术方法。     

土地利用动态变化的空间分析测算模型

论文首先从土地利用变化的空间涵义出发,细分出未变化部分、转移部分和新增部分等3种空间类型,并据此对现有测算土地利用变化速率的数量分析和动态度模型进行了评析,提出了修正后的空间分析测算模型,旨在更为精细和准确地测算各土地利用类型的动态变化程度;并以北京城市边缘区的土地利用变化作为案例,对3种模型的测算结果进行了比较分析。结果表明:空间分析测算模型由于细分并同时考虑了各土地利用类型的空间转移及新增过程,能更为准确地测算出各种土地利用类型的动态变化程度与速率。     

Making resources work more efficiently – the importance of supply chain partnerships

State and federal governments in Australia have implemented a range of assistance programs for manufacturing industries to become more resource efficient and reduce waste. While many of these programs focus on Cleaner Production at single sites, an increasing number of assistance programs are offered across supply chains. Sustainability Victoria, a Victorian government authority, supports projects that focus on resource efficiencies across supply chains in key industry sectors.In this study, tools were adapted and utilised to identify efficiency potentials and losses across supply chains in the timber furniture manufacturing and the food industry sector. In this respect, waste generation and value loss due to inefficient use of critical materials within the processes were estimated from purchase and waste handling data. Primary companies were chosen to undertake efficiency trials that could demonstrate value gain across the supply chain.This study describes the realisation of greater efficiencies in material usage when engaging proactively with supply chain partners immediately adjacent to the primary company. Demonstration trials confirmed that through a more integrated approach among supply chain partners the potential in using materials more efficiently and design processes can lead to enhanced productivity without compromising environmental burden. Hence, the study describes targeted resource efficiency, recycling and process optimisation opportunities as identified in the supply chain trials on timber furniture manufacturing and food industries.     

土地利用和土地覆盖变化研究模型综述

本文综述了全球变化研究中土地利用和土地覆盖变化（ＬＵＣＣ）的主要模型,重点介绍了植被模型和引入社会驱动力的ＬＵＣＣ模型,并归纳出ＬＵＣＣ模型的以下发展趋势：①新一代的ＬＵＣＣ模型应该能够模拟ＬＵＣＣ的主要社会经济和自然驱动力,包括从ＬＵＣＣ到驱动力和全球变化的主要反馈关系；②具有明确的空间关系,能够以适当的空间分辨率,比较好地预测长期的（５０～１００ａ）土地利用和覆盖变化及有关的生物物理参数,如植被特征、资源的积聚和退化等；③能够更好地认识ＬＵＣＣ与其主要驱动力之间的关系在局地、区域和全球尺度上的动态和后果；充分考虑土地利用和覆盖变化对政策、技术进步、人口增长、经济发展、市场变化等社会变量的灵敏性,此外,还应注意意识、信仰等文化因素的影响；④发展新的ＬＵＣＣ建模方法,使ＬＵＣＣ模型能够与其它类型的全球变化模型,特别是气候模型建立联系。     

土地功能与土地利用表征土地系统和景观格局的差异研究——以陕西省蓝田县为例

论文依据土地提供主要服务的差异将土地利用功能划分为3 个大类和6 个亚类;通过对比研究区2010 年与2020 年土地利用类型变化和土地功能的变化,分析两者表征土地系统变化的差异;再利用5 个景观格局指数对比分析土地利用类型变化和土地功能类型变化对景观的影响,探索两者表征景观的差异。通过上述分析得出如下结论：①土地利用类型与土地功能类型均能表征不同类型间的转化,但前者可更为细致地表达出土地功能所包含土地类型间的转化;②在土地利用类型不发生变化的情况下,土地功能依然可以表征土地系统的变化;③土地功能变化分析能得到更为宏观的景观空间特征。     

城市餐厨垃圾产量的空间降尺度模拟

文章以厦门岛为例,采用多元回归模拟和空间分析技术相结合的方法,选取了与厦门岛城市餐厨垃圾产量相关的土地利用、GDP、人口等相关社会经济地理因子进行空间化模拟研究。结果表明:(1)所选地理因子均对餐厨垃圾密度空间分布有一定影响,其中商住混合用地、商业服务用地、城镇住宅用地和城中村用地等土地利用类型的面积比例是主要的影响因子。(2)受多种因素共同影响,筼筜湖周边及厦门岛西南等商业繁华的区域餐厨垃圾密度较高,呈现空间集聚效应。(3)模型验证结果较为理想,各街道内餐厨垃圾总量模拟值与统计值比较符合,实现了厦门岛餐厨垃圾总量的降尺度模拟,是研究城市餐厨垃圾分布规律和实现餐厨垃圾产量空间化的一种尝试,以便为城市餐厨垃圾科学管理和决策提供参考,为餐厨垃圾资源化回收利用提供基础空间数据。     

Product service systems in the automobile industry: contribution to system innovation?

This article investigates the actual and potential contribution that product service systems (PSSs) can make in moving beyond incremental technological improvements towards a focus on behavioural changes and system innovation in the automobile industry. It begins by discussing the means by which existing and planned PSS initiatives can be evaluated in terms of their contribution towards innovation at the system level in the automotive industry. Building on and expanding earlier work, it is suggested that they should be assessed against an expanded set of five key evaluative criteria including: evidence of ‘higher-order’ learning amongst stakeholders; changes in infrastructure and institutional practice; changes in vehicle design, manufacture and end-of-life management; changes in vehicle ownership structure; and changes in modes of producer–user interactions. Following this discussion, the article provides a structured overview of some current and planned PSS initiatives at the empirical level in the automotive industry. The identified initiatives are then assessed against the key evaluative criteria in an effort to reveal their actual or potential contribution to meeting the sustainability challenges of the automotive industry. Based on this exercise, it is argued that since most current initiatives do not unify these key elements of a PSS in a single coherent system they do not constitute ‘complete’ versions of PSS, and therefore, fail to deliver the full range of envisaged benefits in contributing towards system innovation. The article concludes by outlining some key areas for future research into potential strategies to address such challenges.     

土地利用/覆被变化研究的几个问题

近年来土地利用/覆被变化研究取得了许多进展,理论和研究方法有很大发展。其主要趋向是,重视从动态过程角度进行土地利用/覆被变化的分类;强调将土地利用/覆被变化的驱动力区分为自然驱动力和社会经济驱动力,后者则受到研究者越来越大的重视;强调土地利用/覆被变化的模型必须有相应理论的支持,而且所建模型应能动态地模拟不同土地利用之间的竞争;此外,强调在土地利用与土地覆被分类、土地利用/覆被变化的驱动力研究及影响分析中,要重视空间尺度和时间尺度问题。     

CO2 emission reduction for Japanese petrochemicals

Energy efficiency in the Japanese industry is one of the highest in the world. As a consequence, reduction of CO₂ emissions is considered to be difficult and costly. However little attention has been paid as of yet to changes related to so-called non-energy use of fossil fuels. The analysis in this paper suggests that a large number of options exist for emission reduction in the Japanese petrochemical industry. This includes the introduction of biomass feedstocks, the introduction of new catalytic production processes, and changes in waste handling. The use of bioplastics and the use of CO₂ feedstocks seem costly options for GHG emission reduction that should not be applied on the short term. Japanese GHG emissions can be reduced by 7.7% if the optimal set of emission mitigation options is applied. About 60 Mt emission reduction (4.9%) can be achieved by changes on the supply side, another 35 Mt emission reduction (2.8%) can be achieved by changes in waste management. While changes in waste management can be implemented before 2010, biomass introduction on the supply side will probably require a longer lead-time. About half of the emission reduction is cost–effective, but will require further technology development. The other half can be achieved at a cost level of 10,000 yen/t CO₂ (80 US$/t CO₂). The latter part is based on proven technology that is currently not cost–effective.     

Making the seafood industry more sustainable: creating production chain transparency and accountability

The sustainable seafood area has seen experiments with market-based approaches in the US and Europe since the mid-1990s. These include consumer campaigns and Marine Stewardship Council certification. Such consumption strategies have made much progress but need to focus more on how production and consumption intersect. Because producers, their impacts and implementation of sustainable fishing practices are currently unidentifiable, it is difficult to tell whether industry is changing. This article argues that seafood producers can be made more accountable for their production impacts through taking a production chain view, making producers more transparent and creating production chain pressures.     

我国环保产业发展现状和展望

在过去几十年里，我国环保事业不断发展，但是，总的发展速度滞后于国民经济发展的速度。而随着国民经济的持续高速增长，必然对生态环境造成很大压力。我国政府已认识到环境保护可持续发展的重要性，以及加快发展环保产业的紧迫感，国家将加大环保产业的投资和管理力度，这就给环保产业创造了巨大的发展空间和潜在的市场，因此，环保产业也必将成为本世纪的新的投资热点和竞争焦点。     

人工湿地污染物降解模型研究

近年来,人工湿地作为一种绿色、高效的污水处理技术,得到了长足发展和广泛应用。文章综述了人工湿地数学模型的研究进展,重点介绍国内外已成功应用的“箱式”模型和基于过程的模型的开发情况。同时分析了这两类模型的优缺点。建模的目的在于深入理解湿地内部污染物去除过程,从而优化设计参数,指导人工湿地在国内的实践应用。但现阶段,人工湿地去除污染物的内部机制尚未得到定量化,可见湿地模型的未来发展趋势在于对湿地内部过程的深入理解。