地震荷载作用下埋地玻璃钢夹砂管的动力响应分析

玻璃钢夹砂管在土木水利工程领域得到了愈来愈广泛的应用,但现有的埋地管道地震响应分析模型大多不考虑管-土动力相互作用,且多针对均质材料管道,无法应用于具有明显层状复合材料结构特征的玻璃钢夹砂管。基于玻璃钢夹砂管的层状复合材料结构特征,建立了完整的埋地玻璃钢夹砂管地震响应分析模型,在数值分析模型中,考虑了管-土间复杂的动力相互作用,以及地震散射波从有限域向无限域的传播。算例分析表明,所建立的埋地玻璃钢夹砂管地震响应分析模型可合理地分析埋地玻璃钢夹砂管在地震荷载作用下的动力响应。     

代森锰锌和ND－901中代森锰锌在大棚黄瓜上残留动态的研究

采用顶空气相色谱（GLC-HS）分析技术测定了代森锰锌、ND－901中代森锰锌在大棚黄瓜上的残留动态。喷施70％代森锰锌可湿性粉剂的500倍、250倍药液,测出黄瓜上原始沉积量分别为0.88～2.70mg/kg、1.11～3.79mg/kg;半衰期为1.6～9.5天、2.3～10.9天。黄瓜叶片上原始沉积量分别为148.01～164.08mg/kg、246.26～254.51mg/k;半衰期为15.8～16.2、18.4天。ND－901中代森锰锌的残留量均低于单剂。另外,自来水去污处理可有效地减少瓜上代森锰锌的残留量,平均去污率87％。     

纸塑铝复合包装废物的回收与再生利用现状

通过对典型的垃圾填埋场和复合包装再生利用企业的调研,分析了我国现有复合包装废物产生与回收再生利用的现状.并针对纸塑铝复合包装材料的结构和特点,对现有复合包装材料的再生利用技术进行研究比较,指出了我国复合包装回收利用过程中亟待解决的问题及未来的研究方向.     

Recycling disposable cups into paper plastic composites

The majority of disposable cups are made from paper plastic laminates (PPL) which consist of high quality cellulose fibre with a thin internal polyethylene coating. There are limited recycling options for PPLs and this has contributed to disposable cups becoming a high profile, problematic waste. In this work disposable cups have been shredded to form PPL flakes and these have been used to reinforce polypropylene to form novel paper plastic composites (PPCs). The PPL flakes and polypropylene were mixed, extruded, pelletised and injection moulded at low temperatures to prevent degradation of the cellulose fibres. The level of PPL flake addition and the use of a maleated polyolefin coupling agent to enhance interfacial adhesion have been investigated. Samples have been characterised using tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis. Use of a coupling agent allows composites containing 40 wt.% of PPL flakes to increase tensile strength of PP by 50% to 30 MPa. The Young modulus also increases from 1 to 2.5 GPa and the work to fracture increases by a factor of 5. The work demonstrates that PPL disposable cups have potential to be beneficially reused as reinforcement in novel polypropylene composites.     

水平冲击对单元货物的影响

对分隔式单元货物和单件组合式单元货物进行了水平冲击试验。根据试验结果,分析了在托盘尺寸、中空结构、结构不紧凑等单元货物结构上存在的问题。提出了单元货物包装结构设计的建议。     

Performance and emission characteristic studies on CRDI diesel engine fuelled with plastic pyrolysis oil blended with ethanol and diesel

ABSTRACT

This paper mainly focuses on the utilisation of plastic pyrolysis oil (PPO) and its’ blends with diesel and ethanol in different proportions in a modified diesel engine fitted with common rail direct injection (CRDI) facility. PPO was subsequently blended with diesel and ethanol and characterisation has been done. Experiments were conducted to investigate the impact of injection timing (IT) and injection pressure (IP) on the performance of modified CRDI engine fuelled with PPO and its blends with diesel and ethanol. From the experimental investigations, IT of 10°bTDC and IP of 900 bar were found as best operating parameters to obtain maximum brake thermal efficiency (BTE) with lowered emissions for the fuel combinations utilised in the investigations. PPO as substitute to diesel fuel could be viable if its major concern is to finding permanent resources.     

包装箱用改性聚乙烯在干热气候中的老化行为

目的研究包装箱用改性聚乙烯塑料在极端气候环境下的老化特征与规律。方法在敦煌试验站对改性聚乙烯进行为期36个月的自然老化试验,分析缺口冲击强度的变化规律,采用扫描电镜、傅立叶红外光谱和凝胶色谱技术分析样品曝晒面的显微形貌、微观结构以及分子量及其分布变化情况。结果户外曝晒3个月时,样品表面出现大量连续裂纹,缺口冲击强度下降约40%,改性聚乙烯在干热环境下的老化以分子链的断链和氧化为主。结论改性聚乙烯在干热气候中老化迅速,其包装制品在使用中应尽可能减少户外曝晒时间。     

Floatability of polymer materials modulated by frothers

Flotation tests of 35 polymer materials were carried out to investigate their floatability modulated by frothers. Results of flotation tests demonstrated that polymer resins and soft PVC showed high floatability, floatability of hard PVC plastics was relatively low and was related to the frothers, and there exists significant difference in the floatability of different post-consumer plastics. Flotation rate of post-consumer plastics varies from 0% to 100%. Furthermore, three-category low-energy surface (LES) was defined based on the hydrophile index of the materials involved in this paper, and an adsorption model was proposed to explain the results of flotation and to discuss the floatability of polymer materials modulated by frothers. Frother molecules are prone to adsorb on the surface of bubble rather than LES at relatively low concentration, bubble adsorbed by frother molecules is prone to approach first-category LES rather than third-category LES, and the structure of liquid film is formed on the first-category LES at large concentration. Floatability of polymer materials modulated by frothers is further discussed: frothers increase the floatability of the first-category LES but decrease the floatability of the third-category LES, while the floatability of the second-category LES is related to the type of frothers.     

Residues of dicofol on cucumber grown under plastic covers in jordan

Abstract

Residues of dicofol were determined on cucumber leaves and fruits under plastic house (PH) and plastic tunnels (PT). Five sprays, 8 d apart, were applied at 0.15% concentration. initial deposits on leaves were 48 and 58 ppm under PH and PT, respectively. In the last sampling date of leaves, the amounts of 191 and 135 ppm were detected under both cultures, respectively. There was a continuous increase in the initial residue after each spray. The highest amount of dicofol (401) was determined 1 d after the fifth spray under PH. The exposure to high residues may pose a risk to fieldworkers.

On cucumber fruits, residues of 0.95 and 1.60 ppm were determined 1 d after the fourth spray under PH and PT, respectively. These residues decreased after 4 d to 0.40 and 1.49 ppm, respectively. Almost no detectable residues could be determined 8 d after sprays number 4 and 5 under both cultures. All dicofol residues on the fruits were below the tolerance level of 2 ppm.     

浙江省包装印刷行业挥发性有机物排放特征及排放系数

本文通过2105年浙江省254家包装印刷企业的调查数据,剖析了该行业原辅料组分及挥发性有机物(VOCs)污染治理现状,并筛选出100家典型企业,按印刷工艺划分阐述包装印刷行业VOCs排放特征、核算VOCs排放系数.结果表明,浙江省近2/3包装印刷企业未能有效处理VOCs,且大部分企业仍使用溶剂型原辅料,主要排放污染因子为乙酸乙酯、异丙醇、乙醇、乙酸丙酯、乙酸丁酯等9种物质.全省包装印刷行业VOCs平均排放系数为0.485 kg·kg~(-1),其中凹印工艺排放系数最高,为0.634 kg·kg~(-1).与物料衡算法计算值相比,由排放系数得到的排放量误差控制在15%以内.