Investigating mechanical properties and durability of concrete containing recycled rubber ash and fibers

This article investigates the suitability of utilizing end of life rubber tyre particles in concrete as fine aggregate. Rubber ash and rubber fibers were used to develop two series of rubber ash concrete (series I) and hybrid concrete (series II) mixes. The natural fine aggregate was replaced by rubber ash (by volume of 5%, 10%, 15% and 20%) in series I; whereas in series II, the amount of rubber ash was kept constant at 10% and rubber fiber was introduced as replacement of fine aggregate (by volume of 5%, 10%, 15%, 20% and 25%). The concrete mixes were evaluated for compressive strength, flexural strength, resistance to impact loading, fatigue loading, water penetration and shrinkage strain was evaluated. It was observed that inclusion of rubber ash resulted in the improvement of impact resistance of concrete. The results also show that up to 10% rubber ash and rubber fibers can be utilized as fine aggregate to develop feasible and durable rubberized concrete pavements, crash barriers and paver blocks.

     

Enhanced Macroporous Cationic Chitosan Hydrogel by Freezing and Thawing Method with Superadsorption Capacity for Anionic Dyes

Journal of Polymers and the Environment - In this study, we have developed a simple technique to prepare cationic chitosan hydrogel with interconnected porous structure using freeze–thaw...     

Evaluation of mentum deformities of Chironomus spp. (Chironomidae: Diptera) larvae using modified toxic score index (MTSI) to assess the environmental stress in Juru River Basin, Penang, Malaysia

Morphological mentum deformities which represent sublethal effect of exposure to different types of pollutants were evaluated in Chironomus spp. larvae inhabiting three polluted rivers of Juru River Basin in northwestern peninsular Malaysia. Using mentum deformity incidences, the modified toxic score index (MTSI) was developed based on Lenat??s toxic score index (TSI). The suggested MTSI was compared with TSI in terms of its effectiveness to identify different pollutants including heavy metals. The MTSI showed stronger relationship to total deformity incidence expressed as percentage. Additionally, the multivariate RDA model showed higher capability of MTSI to explain the variations in heavy metal contents of the river sediments. The MTSI was recommended in bioassessment of water and sediment quality using the mentum deformities of Chironomus spp. larvae from aquatic ecosystems receiving anthropogenic, agricultural, or industrial discharges.     

Effects of population structure on CO2 emissions in South Asian countries: evidence from panel estimation

Environmental Science and Pollution Research - The rapidly changing population structure in South Asian countries is observed to be linked with growing social, economic, and environmental problems....     

黄土区沟道泥沙微生物群落变化特征及其影响因素

在黄土高原沟壑区,通过16S rRNA基因片段和ITS高通量测序,研究沟道泥沙中细菌和真菌群落在上-中-下游的变化特征.结果表明：与沟头相比,把口站的细菌群落中拟杆菌门（Bacteroidetes）与厚壁菌门（Firmicutes）的相对丰度分别增加6.6%和10.5%,而变形菌门（Proteobacteria）的相对丰度降低15.1%;真菌群落中担子菌门（Basidiomycota）的相对丰度增加7.7%,而子囊菌门（Ascomycota）降低30.2%;泥沙中黏粒含量与细菌丰富度（Chao1指数）和多样性（Shannon指数）之间显著负相关（P<0.05）,与真菌的丰富度和多样性无显著相关性;细菌和真菌群落多样性和丰富度的空间差异与SOC、Olsen-P的变化有关（P<0.05）.因此,泥沙中颗粒组成物和养分含量可能是影响沟道微生物群落变化的主要因素.     

Integration of different environmental valuation methods to estimate forest degradation in arid and semi-arid regions

Many factors are aggravating desertification and degradation of forests such as urbanization, droughts, exploitation of natural resources and climate change. The study aims at estimating and assessing the degradation of forests in arid and semi-arid regions. This task however is complicated since the impact of the degradation will be in different forms such as loss of wood, soil erosion and lost recreational areas. Nevertheless the dynamic impact of the degradation is increasing the complexity of analysis since forest once lost is a reduction of value for all subsequent years. This study is considering the value of damages over time and it is using the concept of three environmental valuation methods to estimate the whole impact of the degradation: the habitat equivalency analysis (HEA), the productivity method and the benefit transfer method. The methods were applied to specific values of forests, depending on the best applicability, and the results combined to an overall value loss. The costs are calculated based on the year 2014 with two time horizons: 30 and 100 years. To apply the valuation approach, Jordan as an arid and semi-arid country is chosen. The result shows that the annual costs of environmental degradation of Jordanian forest areas equal about 0.14% of GDP in 2013, proving the enormous value lost to forest degradation or deforestation. The valuation approach can be transferred to other arid or semi-arid areas and stimulate forest conservation activities to prevent further degradation and to save the forest ecosystem services for the future.     

A Quantitative Review of Urban Ecosystem Service Assessments: Concepts,Models, and Implementation

Although a number of comprehensive reviews have examined global ecosystem services (ES), few have focused on studies that assess urban ecosystem services (UES). Given that more than half of the world’s population lives in cities, understanding the dualism of the provision of and need for UES is of critical importance. Which UES are the focus of research, and what types of urban land use are examined? Are models or decision support systems used to assess the provision of UES? Are trade-offs considered? Do studies of UES engage stakeholders? To address these questions, we analyzed 217 papers derived from an ISI Web of Knowledge search using a set of standardized criteria. The results indicate that most UES studies have been undertaken in Europe, North America, and China, at city scale. Assessment methods involve bio-physical models, Geographical Information Systems, and valuation, but few study findings have been implemented as land use policy.

Electronic supplementary material

The online version of this article (doi:10.1007/s13280-014-0504-0) contains supplementary material, which is available to authorized users.     

Stock identification of the Channa striata Inhabiting the Gangetic River System using Truss Morphometry

Russian Journal of Ecology - Landmark-based truss morphometry was used to identify stock structure of striped snakehead, Channa striata, in the river Ganga and its tributaries: river Yamuna and...     

Performance of biotic indices in comparison to chemical-based Water Quality Index (WQI) in evaluating the water quality of urban river

In order to evaluate the water quality of one of the most polluted urban river in Malaysia, the Penchala River, performance of eight biotic indices, Biomonitoring Working Party (BMWP), BMWP^Thai, BMWP^Viet, Average Score Per Taxon (ASPT), ASPT^Thai, BMWP^Viet, Family Biotic Index (FBI), and Singapore Biotic Index (SingScore), was compared. The water quality categorization based on these biotic indices was then compared with the categorization of Malaysian Water Quality Index (WQI) derived from measurements of six water physicochemical parameters (pH, BOD, COD, NH₃-N, DO, and TSS). The river was divided into four sections: upstream section (recreational area), middle stream 1 (residential area), middle stream 2 (commercial area), and downstream. Abundance and diversity of the macroinvertebrates were the highest in the upstream section (407 individual and H′?=?1.56, respectively), followed by the middle stream 1 (356 individual and H′?=?0.82). The least abundance was recorded in the downstream section (214 individual). Among all biotic indices, BMWP was the most reliable in evaluating the water quality of this urban river as their classifications were comparable to the WQI. BMWPs in this study have strong relationships with dissolved oxygen (DO) content. Our results demonstrated that the biotic indices were more sensitive towards organic pollution than the WQI. BMWP indices especially BMWP^Viet were the most reliable and could be adopted along with the WQI for assessment of water quality in urban rivers.