Biodegradation of γ Irradiated Poly 3-hydroxybutyrate (PHB) Films Blended with Poly(Ethyleneglycol)

Poly(3-hydroxybutyrate) (PHB) was evaluated in blends with poly(ethyleneglycol) (PEG) of different weight average molecular weight (Mw = 300, 600, 1,000 and 6,000). Irradiation of the PHB/PEG films was carried out to different levels of irradiation doses (5 and 10 kGy) and the effects were investigated talking into consideration: thermal properties by differential scanning calorimetry (DSC), perforation resistance, water vapor transmission rate and biodegradation in simulated soil. The addition of plasticizer alters thermal stability and crystallinity of the blends. The improvement in perforation resistance due to irradiation was regarded to be a result of the crosslinking effect. Also, biodegradation assays resulted in mass retention improvements with increases in PEG molar masses, PEG concentration and irradiation dose. The irradiation process was shown to hamper the biodegradation mechanism.     

Farmers’ perception of sustainable agriculture and its determinants: a case study in Kahramanmaras province of Turkey

The primary purpose of this study was to assess in quantitative terms farmers’ perceptions of sustainable agriculture and to determine how those are influenced by different socio-economic characteristics and information-seeking behavior of the farmers. The study was conducted in Kahramanmaras province of Turkey and comprised a stratified sample of 208 farmers from four districts of the province. The farmers rated each of the 21 selected sustainable agricultural practices for importance on a 5-point scale, and the total of these ratings formed the sustainable agriculture perception index. The index score was calculated for each farmer and was treated as the dependent variable in the stepwise regression analysis procedure. The independent variables were such socio-economic characteristics as the farming system, the total and irrigated area of the farm, membership of a cooperative society and participation in village administration, and age, education, and income of the farmer; components of information-seeking behavior included use of the mass media (newspapers, radio, and television), use of the Internet, travel, and participation in farming events. The results of the study showed that the higher the socio-economic status (more frequent contact with extension services, higher education, ownership of land, etc.) and the greater the access to information, the greater the perceived importance of sustainable agricultural practices. It is concluded that if policy-makers and extension organizations concentrate on these factors, they are more likely to succeed in making farmers more favorably disposed toward sustainable agriculture.     

Abundance,population structure and claw morphology of the semi-terrestrial crab <Emphasis Type="Italic">Pachygrapsus marmoratus</Emphasis> (Fabricius, 1787) on shores of differing wave exposure

Wave action is known to influence the abundance and distribution of intertidal organisms. Wave action will also determine the duration and suitability of various foraging windows (high-tide and low-tide, day and night) for predation and can also affect predator behaviour, both directly by impeding prey handling and indirectly by influencing prey abundance. It remains uncertain whether semi-terrestrial mobile predators such as crabs which can access intertidal prey during emersion when the effects of wave action are minimal, are influenced by exposure. Here, we assessed the effect of wave action on the abundance and population structure (size and gender) of the semi-terrestrial intertidal crab Pachygrapsus marmoratus on rocky shores in Portugal. The activity of P. marmoratus with the tidal cycle on sheltered and exposed shores was established using baited pots at high-tide to examine whether there was activity during intertidal immersion and by low-tide searches. Because prey abundance varies along a wave exposure gradient on most Portuguese shores and because morphology of crab chelipeds are known to be related to diet composition, we further tested the hypothesis that predator stomach contents reflected differences in prey abundance along the horizontal gradient in wave exposure and that this would be correlated with the crab cheliped morphology. Thus, we examined phenotypic variation in P. marmoratus chelipeds across shores of differing exposure to wave action. P. marmoratus was only active during low-tide. Patterns of abundance and population structure of crabs did not vary with exposure to wave action. Stomach contents, however, varied significantly between shores of differing exposure with a higher consumption of hard-shelled prey (mussels) on exposed locations, where this type of prey is more abundant, and a higher consumption of barnacles on sheltered shores. Multivariate geometric analysis of crab claws showed that claws were significantly larger on exposed shores. There was a significant correlation between animals with larger claws and the abundance of mussels in their stomach. Variation in cheliped size may have resulted from differing food availability on sheltered and exposed shores.     

Analysing the determinants of environmental technology investments. A panel-data study of Spanish industrial sectors

The aim of this paper is to empirically assess the determinants of environmental technology investments in the Spanish industrial sectors with the help of panel data econometric techniques. The paper confirms the relevance of the stringency of environmental regulation to explain overall investment patterns in environmental technologies. These investments are also positively related to human and physical capital intensity and R&D intensity, and negatively related to the export intensity of sectors. Furthermore, the study shows that the determinants for investments are likely to differ between environmental technology types (i.e., end-of-pipe versus cleaner technologies).     

An investigation on the use of shredded waste PET bottles as aggregate in lightweight concrete

In this work, the utilization of shredded waste Poly-ethylene Terephthalate (PET) bottle granules as a lightweight aggregate in mortar was investigated. Investigation was carried out on two groups of mortar samples, one made with only PET aggregates and, second made with PET and sand aggregates together. Additionally, blast-furnace slag was also used as the replacement of cement on mass basis at the replacement ratio of 50% to reduce the amount of cement used and provide savings. The water–binder (w/b) ratio and PET–binder (PET/b) ratio used in the mixtures were 0.45 and 0.50, respectively. The size of shredded PET granules used in the preparation of mortar mixtures were between 0 and 4 mm. The results of the laboratory study and testing carried out showed that mortar containing only PET aggregate, mortar containing PET and sand aggregate, and mortars modified with slag as cement replacement can be drop into structural lightweight concrete category in terms of unit weight and strength properties. Therefore, it was concluded that there is a potential for the use of shredded waste PET granules as aggregate in the production of structural lightweight concrete. The use of shredded waste PET granules due to its low unit weight reduces the unit weight of concrete which results in a reduction in the death weight of a structural concrete member of a building. Reduction in the death weight of a building will help to reduce the seismic risk of the building since the earthquake forces linearly dependant on the dead-weight. Furthermore, it was also concluded that the use of industrial wastes such as PET granules and blast-furnace slag in concrete provides some advantages, i.e., reduction in the use of natural resources, disposal of wastes, prevention of environmental pollution, and energy saving.     

Soil remediation time to achieve clean-up goals II: Influence of natural organic matter and water contents

This work reports a relatively rapid procedure for the forecasting of the remediation time (RT) of sandy soils contaminated with cyclohexane using vapour extraction. The RT estimated through the mathematical fitting of experimental results was compared with that of real soils. The main objectives were: (i) to predict the RT of soils with natural organic matter (NOM) and water contents different from those used in experiments; and (ii) to analyse the time and efficiency of remediation, and the distribution of contaminants into the soil matrix after the remediation process, according to the soil contents of: (ii1) NOM; and (ii2) water. For sandy soils with negligible clay contents, artificially contaminated with cyclohexane before vapour extraction, it was concluded that: (i) if the NOM and water contents belonged to the range of the prepared soils, the RT of real soils could be predicted with relative differences not higher than 12%; (ii1) the increase of NOM content from 0% to 7.5% increased the RT (1.8-13 h) and decreased the remediation efficiency (RE) (99-90%) and (ii2) the increase of soil water content from 0% to 6% increased the RT (1.8-4.9 h) and decreased the RE (99-97%). NOM increases the monolayer capacity leading to a higher sorption into the solid phase. Increasing of soil water content reduces the mass transfer coefficient between phases. Concluding, NOM and water contents influence negatively the remediation process, turning it less efficient and more time consuming, and consequently more expensive.     

县域土地利用细碎度综合度量与空间分异研究——以江苏省东海县为例

土地细碎化是与土地规模经营理念相背离的一种土地形态,细碎化的土地经营模式会造成土地利用效率下降、粮食减产以及景观美观度降低等一系列问题。目前,土地细碎化程度的衡量多通过细碎度表征,但尚无统一标准,且主要针对农用地。以江苏东海县为例,首先结合景观指数与主成分分析,分别计算耕地、基础设施用地、居民点用地以及生态用地的细碎度,再通过系统聚类,分析不同地类细碎度组合的地域分异特征。结果显示：不同用地类型的细碎度是自然、社会经济的综合影响结果,耕地细碎度与居民点细碎度有着较显著的正相关关系,与生态用地细碎度有着较显著的负相关关系,基础设施用地细碎度和居民点细碎度存在一定的正相关关系,与生态用地细碎度存在一定的负相关关系,土地细碎度基于不同自然、社会经济条件,其分区也有着特定的区位特征。探讨不同用地类型细碎度间的关联性及空间分异特征可以为土地利用、经济发展以及景观改善等提供科学的引导     

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.     

Landscape evaluation: comparison of evaluation methods in a region of Spain

Landscape evaluation is now widely recognised as a powerful, interdisciplinary, environmental research method. The aim of the present work was to compare two landscape evaluation methods as part of a physical planning process: the cartographic assessment method and the in situ assessment method. This comparison was performed using an area of the Montes de Toledo, in the centre of Spain. Both methods provided similar results for the majority of the landscape units studied. This shows that the cartographic method can be successfully used in landscape evaluation, allowing important savings in terms of fieldwork. However, this is only the case when the information provided by the available maps is sufficiently accurate to allow the correct assignment of coefficients by a panel of experts.