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1.
The use of different input data, functional units, allocation methods, reference systems and other assumptions complicates comparisons of LCA bioenergy studies. In addition, uncertainties and use of specific local factors for indirect effects (like land-use change and N-based soil emissions) may give rise to wide ranges of final results. In order to investigate how these key issues have been addressed so far, this work performs a review of the recent bioenergy LCA literature. The abundance of studies dealing with the different biomass resources, conversion technologies, products and environmental impact categories is summarized and discussed. Afterwards, a qualitative interpretation of the LCA results is depicted, focusing on energy balance, GHG balance and other impact categories. With the exception of a few studies, most LCAs found a significant net reduction in GHG emissions and fossil energy consumption when bioenergy replaces fossil energy.  相似文献   

2.
An array of emerging technologies, from electric vehicles to renewable energy systems, relies on large‐format lithium ion batteries (LIBs). LIBs are a critical enabler of clean energy technologies commonly associated with air pollution and greenhouse gas mitigation strategies. However, LIBs require lithium, and expanding the supply of lithium requires new lithium production capacity, which, in turn, changes the environmental impacts associated with lithium production since different resource types and ore qualities will be exploited. A question of interest is whether this will lead to significant changes in the environmental impacts of primary lithium over time. Part one of this two‐part article series describes the development of a novel resource production model that predicts future lithium demand and production characteristics (e.g., timing, location, and ore type). In this article, part two, the forecast is coupled with anticipatory life‐cycle assessment (LCA) modeling to estimate the environmental impacts of producing battery‐grade lithium carbonate equivalent (LCE) each year between 2018 and 2100. The result is a normalized life‐cycle impact intensity for LCE that reflects the changing resource type, quantity, and region of production. Sustained growth in lithium demands through 2100 necessitates extraction of lower grade resources and mineral deposits, especially after 2050. Despite the reliance on lower grade resources and differences in impact intensity for LCE production from each deposit, the LCA results show only small to modest increases in impact, for example, carbon intensity increases from 3.2 kg CO2e/kg LCE in 2020 to 3.3 kg CO2e/kg LCE in 2100.  相似文献   

3.
基于改进的相对生态风险模型,从风险源强度、受体暴露度以及风险效应三方面构建土地利用生态风险评价指标体系,以子流域为单元分析南京地区土地利用生态风险空间分异及影响因素,结果表明:综合生态风险值总体分布较分散,高风险区位于江北八百河流域、老山北坡及南坡河系、石臼湖流域,风险源强和受体暴露度较高,风险效应值较低,潜在生态风险很高,应重点实施环境治理,强化土地生态环境建设;较高风险区位于一干河、二干河、句容河、秦淮中游、江宁河、向阳河、固城湖、境外常州太湖流域,风险源强和受体暴露度中等,应加强环境治理,强化土地利用规划引导与集约利用;较低和低风险区包括境外沿江八卦洲、沿江靖安板块、沿江秦淮河、沿江汤水河、沿江滁河、横溪河、牛首河、前进河、马鞍山长江流域,风险源强和受体暴露度较低,风险效应值低,主要分布于沿江以及山地丘陵河流上游地区,沿江流域近年排污治理力度较大有效保证了低风险源强值,而山地丘陵河流上游植被覆盖度一般较高,人为影响相对较弱,应注重生态环境维护和土地集约利用;其他流域综合生态风险中等,应加强生态环境监测,防止生态环境恶化。  相似文献   

4.
Abstract

A detailed investigation was conducted to understand the contamination characteristics of a selected set of heavy metals (HMs) in 34 campus dust samples from Huaxi University Town. The HMs spatial distribution analysis based on ArcGIS software, the geo-accumulation index (Igeo) and health risk model were employed for evaluation, and multivariate statistical methods were used to identify possible sources. Results showed that the mean concentrations of Cu, Zn, Pb, Cr, Ni, and Cd were 68.18, 123.81, 45.26, 140.36, 47.26, and 0.47?mg/kg, respectively. The spatial distribution characteristics displayed that the relatively large concentrations for the analyzed HMs were mainly located at both teaching areas and students’ dormitory areas. The average values of Igeo indicated that HMs contamination level followed the decreasing trend of Cd?>?Cu?>?Cr?>?Pb?>?Ni?>?Zn. The health risk assessment results indicated that HMs in campus dust generally do not pose any immediate health risk for both adult males and adult females but the cumulative effect is a matter of concern. The sources analyses demonstrated that Cu, Zn, Cr, and Cd, primarily from motor vehicle emission and waste incineration, Pb predominantly originated from construction source, while Ni had the mixed sources of nature and traffic.  相似文献   

5.
分形理论及其在土壤空间变异研究中的应用   总被引:10,自引:0,他引:10  
Zhang FS  Liu ZX 《应用生态学报》2011,22(5):1351-1358
土壤具有不同程度的空间变异性,土壤空间变异研究对于土壤管理有重要意义.本文简要综述了分形理论及其在土壤空间变异研究中的应用,重点讨论了利用矩方法计算土壤属性分形维,多重分形分析土壤空间变异性及基于多重分形谱参数的土壤属性尺度转换.早期研究验证了分形理论在分析土壤空间变异中的有效性和应用潜力,国内外近期研究则报道了利用分形及多重分形理论分析土壤空间变异的最新进展.分形理论可以成为量化土壤属性空间变异性及尺度转换的重要工具.  相似文献   

6.
Greenhouse gas emissions from small and medium enterprises (SMEs) account for 70% of the industrial pollution in the European Union. Owing to limited economic and human resources, only a few SMEs start procedures to evaluate the environmental impact of processes and products through life cycle assessment (LCA). In this work, a cluster life cycle assessment (Cluster‐LCA) is proposed as an instrument for the diffusion and realization of LCA analysis in clustered SMEs. This methodology is illustrated with a case study in the tanning cluster in Tuscany. The different characteristics of the methodology are analyzed by identifying the intrinsic strengths, weaknesses, opportunities, and threats. The application of this methodology in a particular cluster is then discussed in order to gather some helpful insight for the application of this methodology in different clusters.  相似文献   

7.
刘春芳  王川 《生态学报》2018,38(20):7300-7311
生境质量是生态系统服务水平的重要表征,是区域生态安全保障和人类福祉提升的关键环节,评估土地利用变化引起的生境质量时空演变可为区域生态保护和土地管理提供科学依据。以典型黄土丘陵区县域——榆中县为例,基于Arc GIS平台和InVEST模型探讨了该县1995、2005和2015年生境质量空间格局及其演变特征。结论如下:(1)研究区土地类型和景观格局变化明显,主要土地利用变化是耕地转向建设用地和林地,以及草地和耕地之间的相互转变,这些变化导致景观异质性增强和破碎度上升。(2)生境质量空间格局一直表现为"南部高、中部居中、北部低"的态势。生境质量上升区域主要在北部,原因是"退耕还林"及"生态北山"工程的实施使得林地面积增加,下降区域主要在中部,主要是由建设用地扩张占用耕地造成的。(3)生境质量热点以及"H-H"型聚集区主要位于南部山区,而冷点和"L-L"聚集区主要位于北部黄土丘陵区,2015年生境质量空间集聚程度较1995年有所增强,"H-H"聚集区增加0.68%,"L-L"聚集区增加0.67%。对该类型区域生境质量优化提出了相应的政策建议。  相似文献   

8.
Human–wildlife conflicts have intensified by many folds and at different levels in recent years. The same is true in the case of the Hindu Kush Himalaya (HKH), the roof of the world, and a region known for its wealth in biodiversity. We present a systematic literature review (SLR) using the search, appraisal, synthesis, and analysis (SALSA) framework; and for spatial and network analysis, we employed the VOSviewer software. The review—covering 240 peer—articles within a span of 27 years (from 1982 to 2019)—revealed that in the last decade, there was a 57% increase in publications but with a disproportionate geographical and thematic focus. About 82% of the research concentrated on protected areas and large carnivores and mega herbivores played a big role in such conflicts. About 53% of the studies were based on questionnaires, and the main driver reported was habitat disturbance of animals due to land‐cover change, urbanization, and increase in human population. On the management front, the studies reported the use of traditional protection techniques like guarding and fencing. Our analysis of 681 keywords revealed a prominent focus on ‘human‐wildlife conflict,’ ‘Nepal,’ ‘Bhutan,’ ‘Snow Leopard,’ and ‘Leopard’ indicating the issue linked with these species and countries. The involvement of 640 authors from 36 countries indicates increasing interest, and Nepal and India are playing key roles in the region. As for the spatial analysis that was conducted, while it showed regional variations, there were conspicuous limitations in terms of having a transboundary focus. Thus, particular attention ought to be paid to building transboundary partnerships and improving management interventions; there is also a pressing need to understand the patterns of human–wildlife convergence, especially involving meso‐mammals.  相似文献   

9.
Question: Can species compositional dissimilarity analyses be used to assess and improve the representation of biodiversity patterns in a priori ecological classifications? Location: The case study examined the northern‐half of the South‐east Queensland Bioregion, eastern Australia. Methods: Site‐based floristic presence–absence data were used to construct species dissimilarity matrices (Kulczynski metric) for three levels of Queensland's bioregional hierarchy – subregions (1:500 000 scale), land zones (1:250 000 scale) and regional ecosystems (1:100 000 scale). Within‐ and between‐class dissimilarities were compiled for each level to elucidate species compositional patterns. Randomized subsampling was used to determine the minimum site sampling intensity for each hierarchy level, and the effects of lumping and splitting illustrated for several classes. Results: Consistent dissimilarity estimates were obtained with five or more sites per regional ecosystem, 10 or more sites per land zone, and more than 15 sites per subregion. On average, subregions represented 4% dissimilarity in floristic composition, land zones approximately 10%, and regional ecosystems over 19%. Splitting classes with a low dissimilarity increased dissimilarity levels closer to average, while merging ecologically similar classes with high dissimilarities reduced dissimilarity levels closer to average levels. Conclusions: This approach demonstrates a robust and repeatable means of analysing species compositional dissimilarity, determining site sampling requirements for classifications and guiding decisions about ‘lumping’ or ‘splitting’ of classes. This will allow more informed decisions on selecting and improving classifications and map scales in an ecologically and statistically robust manner.  相似文献   

10.
Abstract

The present study, deals with the estimation of degrees of contamination, ecological and human health risk of heavy metals (As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn) in sediments, surface water and fishes, which were collected from middle stretch of Damodar river and ponds at Asansol, which receives outfall of various coal-based industries. Metal content in the premonsoon season was higher than the postmonsoon, due to influx of rainwater. The heavy metal pollution indices (HPI) at some locations was observed up to 1.45 times than recommended value and the cadmium (Cd) was found dominating metal for high HPI value. The Cd concentration in surface water and pore water varied from 2.8 to 14.9?µg/L and 15.3–57.0?µg/L, respectively, which was up to 6 times higher than the permissible limit. Ecological risk assessment for sediments illustrates ‘moderate to considerable ecological risk’, especially because of Cd. Hazard index (HI) calculated to identify potential human health risk by dermal exposure of surface water was <0.1, indicating ‘negligible non-cancer risk’ for all age group of people. However, HI varied from 0.73 to 1.49 for adult and 1.37–2.78 by consumption of fishes indicates children have higher ‘non-cancer risk’ than adult.  相似文献   

11.
Thermoduric pullulanases, acting as starch-debranching enzymes, are required in many industrial applications, mainly in the production of concentrated glucose, maltose, and fructose syrups. To date, however, a single pullulanase, from Bacillus acidopullulyticus, is available on the market for industrial purposes. This review is an investigation of the major advances as well as the major challenges being faced with regard to optimization of the production of extracellular thermoduric pullulanases either by their original hosts or by recombinant organisms. The critical aspects linked to industrial pullulanase production, which should always be considered, are emphasized, including those parameters influencing solubility, thermostability, and catalytic efficiency of the enzyme. This review provides new insights for improving the production of extracellular thermoduric pullulanases in the hope that such information may facilitate their commercial utilization and potentially be applied to the development of other industrially relevant enzymes.  相似文献   

12.
13.

Background and Aims

Plants are expected to maximize their net photosynthetic gains and efficiently use available resources, but the fundamental principles governing trade-offs in suites of traits related to resource-use optimization remain uncertain. This study investigated whether Acer saccharum (sugar maple) saplings could maximize their net photosynthetic gains through a combination of crown structure and foliar characteristics that let all leaves maximize their photosynthetic light-use efficiency (ɛ).

Methods

A functional–structural model, LIGNUM, was used to simulate individuals of different leaf area index (LAIind) together with a genetic algorithm to find distributions of leaf angle (LA) and leaf photosynthetic capacity (Amax) that maximized net carbon gain at the whole-plant level. Saplings grown in either the open or in a forest gap were simulated with Amax either unconstrained or constrained to an upper value consistent with reported values for Amax in A. saccharum.

Key Results

It was found that total net photosynthetic gain was highest when whole-plant PPFD absorption and leaf ɛ were simultaneously maximized. Maximization of ɛ required simultaneous adjustments in LA and Amax along gradients of PPFD in the plants. When Amax was constrained to a maximum, plants growing in the open maximized their PPFD absorption but not ɛ because PPFD incident on leaves was higher than the PPFD at which ɛmax was attainable. Average leaf ɛ in constrained plants nonetheless improved with increasing LAIind because of an increase in self-shading.

Conclusions

It is concluded that there are selective pressures for plants to simultaneously maximize both PPFD absorption at the scale of the whole individual and ɛ at the scale of leaves, which requires a highly integrated response between LA, Amax and LAIind. The results also suggest that to maximize ɛ plants have evolved mechanisms that co-ordinate the LA and Amax of individual leaves with PPFD availability.  相似文献   

14.
CHARGE syndrome is an autosomal dominant inherited disorder characterized by a specific and recognizable pattern of anomalies. De novo mutations or deletions of the gene encoding chromodomain helicase DNA binding protein 7 (CHD7) are the major cause of CHARGE syndrome. In this report, we describe a patient with a typical phenotype characterized by psychomotor retardation, hypertrichosis, facial asymmetry, synophria, failure to thrive, developmental delay and gastro-esophageal reflux, carrying a de novo 6.04 Mb interstitial deletion in 8q12.1q12.3 detected by single nucleotide polymorphism (SNP) array analysis. Despite the deletion includes CHD7 and although the patient shares some of the clinical features of the CHARGE syndrome, she does not fulfill the clinical criteria for this syndrome. To the best of our knowledge, this is the second case with an entire deletion of the CHD7 gene not leading to CHARGE syndrome and, for this reason, useful to expand and further delineate the clinical features associated with the 8q12.1q12.3 deletion. Furthermore, the literature review revealed that the phenotype secondary to duplications of the same region partially overlaps with the phenotype reported in this study. Selected genes that are present in the hemizygous state and which might be important for the phenotype of this patient, are discussed in context of the clinical features.  相似文献   

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