An environmental evaluation of geopolymer based concrete production: reviewing current research trends

In this study we carry out a detailed environmental evaluation of geopolymer concrete production using the Life Cycle Assessment methodology. The literature shows that the production of most standard types of geopolymer concrete has a slightly lower impact on global warming than standard Ordinary Portland Cement (OPC) concrete. Whilst our results confirm this they also show that the production of geopolymer concrete has a higher environmental impact regarding other impact categories than global warming. This is due to the heavy effects of the production of the sodium silicate solution. Geopolymer concrete made from fly ashes or granulated blast furnace slags based require less of the sodium silicate solution in order to be activated. They therefore have a lower environmental impact than geopolymer concrete made from pure metakaolin. However, when the production of fly ashes and granulated blast furnace slags is taken into account during the life cycle assessment (using either an economic or a mass allocation procedure), it appears that geopolymer concrete has a similar impact on global warming than standard concrete. This study highlights that future research and development in the field of geopolymer concrete technology should focus on two potential solutions. First of all the use of industrial waste that is not recyclable within other industries and secondly on the production of geopolymer concrete using a mix of blast furnace slag and activated clays. Furthermore geopolymer concrete production would gain from using waste material with a suitable Si/Al molar ratio in order to minimise the amount of sodium silicate solution used. Finally, by taking into account mix-design technology, which has already been developed for OPC concrete, the amount of binder required to produce a geopolymer concrete could be reduced.     

环境对装备的影响及装备环境工程标准分析

阐述了环境及影响对装备的重要性，研究了MIL-STD-810F、DEFSTAN00-35、NATOSTANG4370、GJB4239等装备环境工程标准的特点，提出了我国开展环境工程的建议。     

Copper slag: optimization of productivity and consumption for cleaner production in dry abrasive blasting

Copper slag, a by-product from copper smelting industry, is widely used as an abrasive material to remove rust, old coating and other contamination in dry abrasive blasting which is an expensive process and results in significant amounts of particulate emissions and spent abrasive. This paper presents models developed to improve productivity and consumption of copper slag as functions of blast pressure, abrasive feed rate, and surface contamination. These models will help industries in selecting optimum process conditions for maximum efficiency and to achieve cleaner production by consuming less materials and energy resources. In addition, the models will greatly assist in evaluation of the life cycle costs for use of copper slag in dry abrasive blasting.     

Integrated environmental assessment and pollution prevention in Vietnam: the case of anthracite production

Using the concept of life cycle analysis, the whole life cycle of anthracite production in Vietnam was assessed and the environmental “hot-spots” were identified. These include (i) dust pollution at coal transfer points or piles in storage; (ii) noise pollution resulting from the usage of heavy equipment, and (iii) high volume of acid and turbid mine water discharged into the environment.Pollution prevention and treatment options were identified and discussed in this study which consists of wet treatment of dust, planning, collection and treatment of mine water, planting of trees for dust and noise reduction as well as minimization of erosion. Some recommendations are made for pollution abatement from coal production and improvement of anthracite production in the region.     

Economic and environmental effects of unilateral climate actions

Unilateral climate policy can be detrimental to global climate protection. Our objective is to provide insight into such a policy, to quantify the risk of carbon leakage, and to investigate the effects related to potential anti-leakage measures. We analyze existing definitions of carbon leakage and propose an alternative, rigorous one, which is different in three respects. The definition is then tested using computable general equilibrium analysis of the global economy and decomposition analysis. We identify a list of parameters that affect not only the magnitude but also the sign of the carbon leakage rate. Manipulating elasticities of substitution suggests that carbon leakage can be either positive or negative. Computable general equilibrium models, which are widely applied, including by the European Commission in this area, should be transparent, and their assumptions call for careful validation. We find that emission limits are properly distributed between sectors covered by the European Union Emissions Trading System and other sectors for the first commitment period (ended in 2012) but not for the second one (ending in 2020), where the target for the non-trading sectors should be reduced relative to the target for the trading sectors in order to equlize marginal abatement costs.     

Minimization of energy use in multipurpose batch plants using heat storage: an aspect of cleaner production

A mathematical technique for optimization of energy use through the exploitation of heat storage in heat integrated multipurpose batch plants is presented in this document. Storage of heat is effected through the use of a heat transfer fluid. The resultant mathematical formulation exhibits a mixed integer linear programming (MILP) structure, which yields a globally optimal solution for a predefined storage size. The concept of heat integration in batch plants with the objective of minimising energy use is indeed an aspect of cleaner production that has received very limited attention in published literature. This is largely because batch plants are perceived to be less energy-intensive compared to their continuous production counterparts which is untrue for some batch operations, like dairy and brewing processes; hence the need for dedicated techniques. Application of the proposed method to an agrochemical facility has shown savings of more than 75% in external utility steam consumption.     

一种粉煤灰加气砼清洁生产新技术的研究

针对粉煤灰加气砼砌块生产的特点，分析了粉煤灰加气砼清洁生产的基本技术，设计了一种粉煤灰加气砼破碎磨粉车间清洁生产新方法，该方法能实现粉煤灰加气砼破碎磨粉车间湿式去尘，并有效提高水、气资源的综合利用率，该方法也可用于其它粉尘排放量大的场所除尘。     

Cleaner manufacture of multipurpose batch chemical and biochemical plants. Scheduling and optimal choice of production recipes

This study presents an approach for cleaner management of multipurpose batch chemical or biochemical plants. Given that manufacture of most of the products could be carried out in multiple ways depending on chosen production recipes, the scheduling framework is extended by involving the choice of appropriate production recipes. Using as optimization criteria the Global or Local Environmental Impact Assessments defined in Minimum Environmental Impact Methodology, the mathematical formulation that results in multi-objective optimization problems is presented for a special class of schedules.The approach is implemented on an example from dairy industry. Production of two types of curds by selection from two available recipes for each one of them is considered. The problem is translated to a single objective. Two most reliable solutions are obtained, which differ in chosen production recipes, milkfat content and units involved for tasks implementation. Comments on the impacts on the load of Biochemical Oxygen Demand at the end of each production cycle due to simultaneous curds manufacturing and contributions of individual dairy wastes in Global Biochemical Oxygen Demand are also provided.     

Accommodating consensus and diversity in environmental knowledge production: Achieving closure through typologies in IPBES

How can a diversity of perspectives be accommodated in scientific and political consensus on environmental issues? This paper adopts a science and technology studies (STS) approach to examine how the pursuit of consensus-based knowledge and diverse participation, as seemingly contradictory commitments, have been converted into practice in the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES). Through a series of negotiations, these commitments have been translated into a set of situated practices that now dominate this expert panel. Consensus has been achieved through the pursuit of closure, in which meetings of expert and administrator groups produce texts, tables and images that stabilise ostensibly collective decisions. Within this framework, diverse perspectives have been accommodated through the production of typologies, such as lists of comparable options, which allow for the coexistence and commensurability of a range of knowledges and experts. However there is a politics to typologies, which requires specific attention to how decisions are made (deliberation), who participates in them (participation), and the extent to which these participants are representative of broader knowledge and policy communities (representation). While the potential of typologies to accommodate consensus and diversity offers the hope of realising ‘unity in diversity’ for both environmental knowledge and policy, recognising the politics of their production is important for more equitable processes of environmental governance.     

Environmental impact of cement production: detail of the different processes and cement plant variability evaluation

This study evaluates the environmental impact of the cement production and its variations between different cement plants, using Life Cycle Impact Assessment. For that purpose, details of the cement production processes are investigated in order to show the respective part of raw materials preparation and clinker production using environmental impacts calculated with CML01 indicators. For the kiln emission data, a European pollutant emission register for French intensive industries is used to quantify the variability of indicators between cement plants. For the CML01 indicators that are controlled by kiln emissions, some of them (i.e. global warming, photochemical oxidation) show variations between cement plants between 20 and 30%, as for other (i.e. acidification, eutrophication, terrestrial ecotoxicity) variations are greater than 40% due to the lack of accurate measurements on both pollutant content and annual flow. Finally, a normalisation, using Western Europe yearly emissions is performed and permits to highlight among all the CML01 indicators which ones are the main impacts for the cement production. Abiotic depletion, global warming, acidification and marine ecotoxicity are the four identified impacts.     

Geographic distribution and environmental characterization of livestock production systems in Eastern Africa

The central role played by livestock in the livelihoods of rural households in the developing world is seldom fully appreciated by policy makers, development agencies and donors. Knowledge gaps in the geographic distribution and environmental determinants of farming systems, especially if viewed through the livestock lens, compound this problem. We have produced a map of pastoral, agro-pastoral and mixed farming systems across Eastern Africa, by analysing datasets collected in the framework of livelihood analysis. Input data were gathered between 2000 and 2007 by various emergency and development agencies for Djibouti, Eritrea, Kenya, Somalia, Uganda and parts of Ethiopia and Sudan. A quantitative definition of the production systems is adopted, based on the ratio of livestock- to crop-derived income. The resulting livelihood-based map of livestock production systems was compared through correspondence analysis to an alternative livestock production systems map, produced independently from environmental data. Convergence between the two mapping approaches was evident. The geographic distribution of the livestock production systems was also modelled using multivariate analysis of remotely sensed and other geospatial datasets. Models show high statistical accuracy, and were thus used to fill the gaps in the observed distribution of livestock production systems. Finally, selected environmental factors underpinning the systems (agro-climatology, human and livestock populations and land cover) were analysed in detail, enabling the livestock production systems to be characterized in terms of them. The regional scope of the map, as well as its direct link with a vast amount of livelihood information, render it a valuable tool for a range of development and research applications, including those related to global change.     

Methods and data for the environmental inventory of contrasting pig production systems

The comparison of the environmental performance of contrasting agricultural production systems using life cycle assessment (LCA) requires very specific data for each production mode, especially for direct emissions on the farm. In a case study of pig production, three contrasting production scenarios were defined: conventional good agricultural practice (GAP), organic agriculture (OA), and red label (RL). An expert panel produced methods for the estimation of emissions for key-processes of these scenarios. Clear differences were obtained for these emissions between the three scenarios. Finally, the summation of the main emissions for the entire life cycle allowed the identification of weak points for each scenario, which can be explained by the differences obtained for the emissions of the key-processes studied.     

Machining efficiency of powder mixed near dry electrical discharge machining based on different material combinations of tool electrode and workpiece electrode

Powder mixed near dry electrical discharge machining (PMND-EDM) is a novel electrical discharge machining (EDM) process. It is proposed to further improve the machining efficiency of dry EDM. The principle of material removal in PMND-EDM is illustrated and its deionization principle is proposed. The influence of residual heat on MRR is analyzed. The concept of superfluous residual heat is proposed. The material removal rate (MRR), the main index of machining efficiency for PMND-EDM process, is researched. Single factor experiments are performed to get effect of peak current, pulse on time, pulse off time, flow rate, tool rotational speed, air pressure and powder concentration on MRR under different material combinations of tool electrode and workpiece electrode. Thermal phenomena in PMND-EDM are illustrated. Effect of each process parameter on MRR of PMND-EDM is gotten and analyzed based on the deionization principle of PMND-EDM. Differences in MRR under different material combinations are found out. Brass tool electrode and W18Cr4V workpiece gain higher MRR under most of discharge conditions, while the superiority of copper tool electrode and 45 carbon steel workpiece in MRR arise when there is improper heat dissipation. The difference is analyzed based on the deionization principle of PMND-EDM.     

Side effects of categorized environmental measures and their implications for impact analysis

Environmental measures have sometimes unintended side effects. The paper focuses on side effects that are the result of relations and feedback mechanisms between economic activities and industries in production–consumption chains. The theoretical framework of the chain analysis tools, life cycle assessment and substance flow analysis is used to define five different types of environmental measures: volume measures (1), efficiency measures (2), end-of-pipe emission reduction measures (3), re-use and recycling (4) and useful application of waste products (5). Each of these types of measures can re-direct substance flow in a different process, thus causing pollutant emissions to the environment to shift to similar or other emissions upstream or downstream in the economic chain. Using this categorization, the occurrence of a number of different processes that can lead to side effects can be predicted.     

Effects of environmental factors on the production and release of matrix-bound phosphine from lake sediments

Effects of pH, temperature, and oxygen on the production and release of phosphine in eutrophic lake sediments were investigated under laboratory tests. Results indicated that the elimination of matrix-bound phosphine was accelerated under initial pH 1 or 12. Phosphine levels could reach maximum under initial pH 10. The contents of phosphine increased with the addition of alkali under pH 4–12. The rates of phosphine production and release from lake sediments varied with temperature. 20°C was the most favorable temperature for the production of matrix-bound phosphine. Oxygen showed little effect on matrix-bound phosphine. Matrix-bound phosphine concentrations in lake sediments were concluded to be dependent on a balance of natural generation and depletion processes. Translated from Acta Scientise Circumstantiae, 2005, 25(5): 681–685 [译自: 环境科学学报]     

The effects of land tenure change on sustainability: human security and environmental change in southern African savannas

Using a human security perspective, we investigate how the history of land tenure changes has driven sustainability in southern African savannas. The paper examines four countries—Botswana, Mozambique, South Africa and Zimbabwe. Two research questions are addressed: first, how has colonial land tenure and distribution affected people's options and capacity to end, mitigate or adapt to risks to their human, environmental and social rights, and what have been the related effects on land uses and degradation? Second, to what extent have post-independence land reforms addressed threats to human security and political causes of land degradation? The inequitable distribution of land and colonial legacy of dual or pluralistic systems of tenure are found to be at the root of many agrarian and environmental problems. Post-independence land reforms have largely failed to address these fundamental issues, sometimes even reinforcing threats to social, economic and environmental sustainability. The skewed distribution of land and resources, insecure rights, and the marginalisation and restriction of savanna livelihood systems have persisted, undermining human security and environmental integrity in the region as well as leading to mounting conflict and insecurity.     

环境条件对浮游藻色素特征的影响及应用研究进展

基于色素分析的浮游藻化学分类方法已经成为从宏观上对浮游藻群落组成和丰度进行定量研究的良好工具。浮游藻化学分类方法的应用需要对藻类色素特征及其在不同环境条件下的变化特点有较充分的了解。本文对在实验室培养条件下,光照和营养盐条件对不同藻种单位细胞色素含量、特征色素对叶绿素a比值的色素特征的影响,以及在淡水、高浑浊河口环境下,多种因素的综合作用、非藻类色素引起的误差等因素的研究进展进行了综述,并阐述了相关应用、存在的问题及未来的展望。     

LCA of environmental and socio-economic impacts related to wood energy production in alpine conditions: Valle di Fiemme (Italy)

An extended Life Cycle Assessment (LCA) is performed for evaluating the impacts of a woody biomass supply chain for heating plants in the alpine region. Three main aspects of sustainability are assessed: greenhouse gas emissions, represented by global warming potential (GWP) impact category, costs and direct employment potential. We investigate a whole tree system (innovative logging system) where the harvest of logging residues is integrated into the harvest of conventional wood products. The case study is performed in Valle di Fiemme in Trentino region (North Italy) and includes theoretical and practical elements. The system boundary is the alpine forest fuel system, from logging operations at the forest stand to combustion of woody biofuels at the heating plant. The functional unit is 1 m³ solid over bark of woody biomass, delivered to the district heating plant in Cavalese (Trento). The relative sustainability of traditional and innovative systems is compared and energy use is estimated. Results show that the overall GWP and costs are about 13 kg CO_2equivalent and 42 euro per functional unit respectively for the innovative system. Along the product supply chain, chipping contributes the greatest share of GWP and energy use, while extraction by yarder has the highest financial costs. The GWP is reduced by 2.3 ton CO_2equivalent when bioenergy substitutes fuel oil and 1.7 ton CO_2equivalent when it substitutes natural gas. The sensitivity analysis illustrates that variations in fuel consumption and hourly rates of costs have a great influence on chipping operation and extraction by cable yarder concerning GWP and financial analysis, respectively. This is confirmed by sensitivity analysis. Better technologies, the use of biofuels along the product supply chain and more efficient systems might reduce these impacts. Replacing the traditional system with the innovative one reduces emissions and costs. A low energy input ratio is required for harvesting logging residues. The direct employment potential is a conflicting aspect and needs further investigations.     

A method for evaluating the overall technical and economic performance of environmental innovations in production cycles

As is demonstrated by a great deal of scientific literature on the subject, an ever-increasing number of businesses are adopting cleaner production as a strategy to minimise the impact of their activities and their products on the environment. However, the range of approaches which are grouped together and given the common name ‘cleaner production’ is quite broad and diversified and includes a variety of innovative solutions that lead to very different results. Indeed, varying results have been obtained; the improvements in that industry has achieved in its environmental performance, both on a single business basis and in the overall product life cycle, as well as in the financial and economic returns. The present study proposes a quantitative method of classification, cleaner production innovations based on technical and economic criteria. The method proposed here is based on improvements made to the environment and the economic benefits to both the single business and to the overall socio-economic system as well as on the inter-relations between these variables.