Long-term engineering properties of recycled plastic lumber used in pier construction

Plastic lumber manufactured using post consumer waste plastic has been proposed as an acceptable material for use in the construction of docks, piers and bulkheads and is touted to outlast conventional wood products due to its strength, durability and resistance to rot. This study examines the long-term engineering properties of plastic lumber manufactured using post consumer waste plastic (TRIMAX, Ronkonkoma, NY). Plastic lumber profiles were used in the decking of a pier built in West Meadow Creek, Old Field, NY during December 1995. Samples of plastic lumber were removed from the deck of the pier periodically over a two-year period and returned to the laboratory for testing. Results of engineering tests showed the in-plane compression modulus (260±30 MPa), dimensional stability and the Shore D surface hardness (60±2) of plastic lumber removed from the pier remained similar to or greater than their pre-placement values. In contrast, significant changes in the modulus of elasticity of plastic lumber were measured with prolonged weathering. The modulus of elasticity of plastic lumber initially decreased from 1370 Pa to 750 Pa following 12 months weathering, a decrease equal to 45% of its pre-placement value and then increased during the second year to close to its initial value. The high variability in the modulus of elasticity should restrict the use of plastic lumber profiles to non-load bearing structural applications.     

从LCA角度评价塑料用品与木制用品对环境的影响

通过对一次性塑料与纸制用品（木制品）的评价研究的基础上，对木制品与塑料制品从生命周期评价（LCA）的角度上对问题作进一步的探讨和研究，得出结论为塑料制品为环保型产品。     

Composition of Floating Debris in Harbours of the United States

As part of a programme to characterize floating anthropogenic debris in the aquatic environment, the US Environmental Protection Agency (EPA) conducted 18 field surveys in the harbours of major metropolitan cities of the east, west, and Gulf coasts of the United States and the Mid-Atlantic Bight. the surveys were designed to provide information on the types, relative amounts, and distributions of aquatic debris in different geographic regions of the United States. Neuston nets (0.33 mm mesh) were used to collect surface debris during outgoing tides on two or three consecutive days in selected areas of each city. After each net tow, the debris, which ranged in size from small resin pellets to large plastic sheeting pieces, was identified, categorized, and counted. the data are being used to qualitatively characterize aquatic debris in coastal metropolitan areas, to examine potential regional variations, and to tentatively identify potential sources.     

General vs. domain specific recycling behaviour—Applying a multilevel comprehensive action determination model to recycling in Norwegian student homes

This paper reports the results of a multilevel structure equation model predicting general and fraction specific self-reported recycling behaviour. The model was tested on a sample of 697 undergraduate students from four Norwegian universities who each reported their degree of participation in the local recycling schemes for paper/cardboard, glass, metal, and plastic. It was demonstrated that variance in recycling behaviour can be divided into a smaller general part that is relatively stable across waste fractions and a specific part that depends on the respective fraction. General recycling behaviour is well predicted by intentions to recycle and recycling habits, whereas perceived behavioural control is to a large extend fraction specific and influences the fraction specific recycling. Perceived behavioural control mediates the influence of the recycling scheme type, distance to recycling containers, and transport mode used to reach the recycling containers.     

Primary and secondary organic aerosol in an urban/industrial site: Sources, health implications and the role of plastic enriched waste burning

PM10 samples were collected from an urban/industrial site nearby Athens, where uncontrolled burning activities occur. PAHs, monocarboxylic, dicarboxylic, hydroxycarboxylic and aromatic acids, tracers from BVOC oxidation, biomass burning tracers and bisphenol A were determined. PAH, monocarboxylic acids, biomass burning tracers and bisphenol A were increased during autumn/winter, while BSOA tracers, dicarboxylic- and hydroxycarboxylic acids during summer. Regarding aromatic acids, different sources and formation mechanisms were indicated as benzoic, phthalic and trimellitic acids were peaked during summer whereas p-toluic, isophthalic and terephthalic were more abundant during autumn/winter. The Benzo[a]pyrene-equivalent carcinogenic power, carcinogenic and mutagenic activities were calculated showing significant (p < 0.05) increases during the colder months. Palmitic, succinic and malic acids were the most abundant monocarboxylic, dicarboxylic and hydrocarboxylic acids during the entire sampling period. Isoprene oxidation was the most significant contributor to BSOA as the isoprene-SOA compounds were two times more abundant than the pinene-SOA (13.4 ± 12.3 and 6.1 ± 2.9 ng/m³, respectively). Ozone has significant impact on the formation of many studied compounds showing significant correlations with: isoprene-SOA (r = 0.77), hydrocarboxylic acids (r = 0.69), pinene-SOA (r = 0.63),dicarboxylic acids (r = 0.58), and the sum of phthalic, benzoic and trimellitic acids (r = 0.44). PCA demonstrated five factors that could explain sources including plastic enriched waste burning (30.8%), oxidation of unsaturated fatty acids (23.0%), vehicle missions and cooking (9.2%), biomass burning (7.7%) and oxidation of VOCs (5.8%). The results highlight the significant contribution of plastic waste uncontrolled burning to the overall air quality degradation.     

Microplastics removal strategies: A step toward finding the solution

• Physical, chemical and biological methods are explored for MPs removal. • Physical methods based on adsorption/filtration are mostly used for MPs removal. • Chemical methods of MPs removal work on coagulation and flocculation mechanism. • MBR technology has also shown the removal of MPs from water. • Global policy on plastic control is lacking. Microplastics are an emerging threat and a big challenge for the environment. The presence of microplastics (MPs) in water is life-threatening to diverse organisms of aquatic ecosystems. Hence, the scientific community is exploring deeper to find treatment and removal options of MPs. Various physical, chemical and biological methods are researched for MPs removal, among which few have shown good efficiency in the laboratory. These methods also have a few limitations in environmental conditions. Other than finding a suitable method, the creation of legal restrictions at a governmental level by imposing policies against MPs is still a daunting task in many countries. This review is an effort to place all effectual MP removal methods in one document to compare the mechanisms, efficiency, advantages, and disadvantages and find the best solution. Further, it also discusses the policies and regulations available in different countries to design an effective global policy. Efforts are also made to discuss the research gaps, recent advancements, and insights in the field.     

Evaluation of recycling policies for PET bottles based on multiattribute utility indices

This study focused on waste plastic, especially the polyethylene telephthalate (PET) bottle as representative waste, which has been assigned as goods to be recycled by the Packaging Waste Recycling Law in Japan. We developed a plastic transport model which explained the entire flow of plastic from the production stage to the disposal stage within an the evaluation model of plastic recycle policy based on multiattribute utility theory. This model is designed to be used by local municipal governments in supporting the evaluation of the PET bottle recycling policy. In evaluating the plastics recycling policy, we selected indices relating to economy, ecology, and rate of resource recycling. The results indicate that when the evaluation of the material recycling policy and thermal recycling policy in the model city were characterized in terms of their economic and environmental aspects the thermal recycling policy had the highest utility within our scenario. Received: July 31, 1998 / Accepted: January 26, 1999     

利用塑性介质挤胀成形三通管接头变形力的研究

此文对利用塑性介质挤胀成形三通管接头变形力进行了实验研究。设计了一套挤胀成形三通管接头的通用装置,并利用此装置进行了三通挤胀成形实验。此研究给出了影响成形过程的一些重要参数。将理论结果与实验结果进行了对比,两者吻合较好。     

关于塑性应变比的测定

此文用直接法和间接法研究了δ值和计算方法对γ值的影响。发现γ值基本上与δ无关。δ只影响其测量精度,δ愈大愈有利于提高γ的测量精度。计算方法对γ值的影响只在δ值较小时。随δ增大,计算方法的影响逐步消除。     

我国废弃塑料回收再利用的现状及对策

废旧塑料难于自然降解,所造成的环境污染日趋严重,回收利用为处理废旧塑料垃圾开辟了减量化、无害化、资源化的道路。通过分析我国废弃塑料产生和回收再利用处理技术的现状,进一步探讨了符合我国国情的废旧塑料回收利用对策。