火烧试验包装箱内部温度无损测试研究

针对火烧试验包装箱内部温度无损测试要求,提出并实施了基于＂黑匣子＂耐高温无线无损测试技术,介绍了其工作原理、系统配置,研究了耐高温的保护方法。该测试技术成功应用于火烧试验包装箱内部温度测试,为结构隔热设计、产品安全评估和修正火烧数值计算模型提供了依据。对无线实时在线测试技术和应用条件进行了探索和研究,进行了相关考核试验。该技术可应用于异常环境、不破坏内部结构、实时在线的试验测试。     

Antimicrobial potential of commercial silver nanoparticles and the characterization of their physical properties toward probiotic bacteria isolated from fermented milk products

The application of nanotechnology in the agriculture and food sector is relatively recent compared to its usage in drug delivery or pharmaceuticals. Therefore, this paper presents a study of the effect of silver nanoparticles on probiotic bacteria based on the example of Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12 and Streptococcus thermophilus ST-Y31 isolated from fermented milk products. Probiotic bacteria are one of the most crucial groups of bacteria for the food industry, because of their claimed health-promoting properties. Studies have shown that the type and concentration of silver nanoparticle solutions have a significant impact on the tested probiotic bacteria which are profitable for the digestive system. In the presence of all tested silver nanoparticles, St. thermophilus ST-Y31 growth was inhibited significantly by the dilution method as opposed to the disk-diffusion method. Both the disk-diffusion and the dilution methods showed no significant differences between L. acidophilus LA-5 and B. animalis subsp. lactis BB-12. The concentrations 2 μg mL^?1 and 0.25 μg mL^?1 had the highest antibacterial activity and statistically significant impacts on the tested probiotic strains. To our knowledge, this is the first report on potential antimicrobial effect of nanosilver against the health-promoting probiotic bacteria L. acidophilus LA-5, B. animalis subsp. lactis BB-12 and St. thermophilus ST-Y31 isolated from fermented milk products.     

The costs and benefits of packaging waste management systems in Europe: the perspective of local authorities

Local authorities are generally in charge of household packaging waste management operations, particularly in countries with Green Dot schemes or similar extended producer responsibility systems. This leads to the need of establishing a system of financial transfers between the packaging industry and the local authorities (regarding the costs involved in selective collection and sorting). In the present study, the costs and benefits of recycling, from the perspective of local authorities, are compared for Portugal, Belgium and Italy (in Lombardia region), adopting the same economic–financial methodology. The results show that the industry is not paying the net cost of packaging waste management. If the savings attained by diverting packaging waste from other treatment operations are not considered, it seems that the industry should increase the financial support to local authorities. However, if the avoided costs with other treatments are considered as a benefit for local authorities, the costs are generally outweighed by the benefits, and the financial support could, therefore, be reduced.     

Recovery and distribution of incinerated aluminum packaging waste

A study was performed into relations between physical properties of aluminum packaging waste and the corresponding aluminum scraps in bottom ash from three typical incineration processes. First, Dutch municipal solid waste incineration (MSWI) bottom ash was analyzed for the identifiable beverage can alloy scraps in the +2mm size ranges using chemical detection and X-ray fluorescence. Second, laboratory-scale pot furnace tests were conducted to investigate the relations between aluminum packaging in base household waste and the corresponding metal recovery rates. The representative packaging wastes include beverage cans, foil containers and thin foils. Third, small samples of aluminum packaging waste were incinerated in a high-temperature oven to determine leading factors influencing metal recovery rates. Packaging properties, combustion conditions, presence of magnesium and some specific contaminants commonly found in household waste were investigated independently in the high-temperature oven. In 2007, the bottom ash (+2mm fraction) from the AEB MSWI plant was estimated to be enriched by 0.1 wt.% of aluminum beverage cans scrap. Extrapolating from this number, the recovery potential of all eleven MSWI plants in the Netherlands is estimated at 720 ton of aluminum cans scrap. More than 85 wt.% of this estimate would end up in +6mm size fractions and were amenable for efficient recycling. The pot furnace tests showed that the average recovery rate of metallic aluminum typically decreases from beverage cans (93 wt.%) to foil containers (85 wt.%) to thin foils (77 wt.%). The oven tests showed that in order of decreasing impact the main factors promoting metallic aluminum losses are the packaging type, combustion temperature, residence time and salt contamination. To a lesser degree magnesium as alloying element, smaller packaging size and basic contaminations may also promote losses.     

包装印刷业VOCs污染特征分析

选取了北京市的14家大型包装印刷企业进行现场采样、监测,统计分析了生产工艺和原辅材料,识别了VOCs污染来源和排放节点。根据不同排放节点的特征搭建了相应的采样系统,并以此为基础考察了VOCs的排放特征、臭氧生成潜势和二次有机气溶胶(SOA)生成潜势。结果表明:包装印刷业所排放的VOCs以醇类和酯类为主;乙醇和异丙醇为主要的臭氧前体物,生产线和烘干集气系统排气口为主要的臭氧生成节点;烷烃和醇类为主要的SOA前体物,烘干集气系统排气口为首要的SOA生成节点。     

包装材料及食品中纳米材料的检测与表征技术

随着纳米技术的发展,纳米材料在包装行业及食品工业中得到了广泛的应用。然而,纳米材料的安全应用高度依赖于对其生物及环境效应的了解。有研究表明,纳米材料对人类健康及生态环境存在着潜在危害,这使得纳米材料的安全性成为毒理学领域的热点研究课题。同时纳米材料的安全性问题也成为纳米复合包装材料及纳米食品研究和开发的新瓶颈。在对纳米材料没有充分认识的情况下,为了消费者和生态环境的安全,必须控制包装材料及食品中纳米颗粒的种类、来源、含量及可能的释放,这就需要可靠的方法对纳米颗粒的性质和结构进行检测及表征。首先,综述了目前纳米材料在复合包装材料及食品加工中的应用,然后总结了包装材料及食品中纳米材料的检测技术及表征方法,例如显微技术、色谱分离技术、光谱与质谱技术等。由于纳米材料的理化性质参数众多,应用多种分析手段来检测和表征纳米材料成为必然。最后对目前检测技术及表征方法的不足和今后发展方向进行了探讨。     

我国包装废物产生及回收现状分析

针对我国包装废物产生、回收、最终处置的各阶段现状进行调查和分析,主要对于我国现阶段塑料、纸制品和金属制品的包装产生消费量进行综合分析,并实地对居民生活小区零散个体回收者的包装废物回收量和包装废物再生企业包装废物原料回收渠道以及最终流入生活垃圾填埋场的包装废物含量进行了调研. 将包装废物产生量、回收量与最终处置量相比较的结果可以看出,现有回收体系对于部分包装废物回收效果较好,例如包装废物中PET聚酯瓶和金属罐的回收效果最好;而没有经济利益的塑料袋几乎完全没有得到回收再生,是回收工作的难点. 再进一步通过对复合包装再生企业和PET聚酯瓶再生企业的回收体系的实例分析,提出我国现存包装废物回收体系中存在的问题.      

基于工艺过程的金属包装业VOCs污染特征

识别金属包装业挥发性有机化合物(volatile organic compounds,VOCs)产生和排放节点,定量分析不同类型生产工艺所排放VOCs的物种及含量,结合最大增量反应活性法和修正的气溶胶生成系数法对行业二次污染进行核算.结果表明,金属包装业排放的VOCs主要为苯系物、醇类、酮类和酯类,苯系物和醇类在不同类型工序和排污节点中贡献较大,酮类和酯类贡献相对较少,单物种浓度最高的VOCs为正丁醇,浓度达269.08mg·m^-3;生产线与相应的排气筒之间VOCs物种浓度相关性较好,但物种种类存在差异;行业的O₃和二次有机气溶胶(secondary organic aerosol, SOA)生成潜势(以O₃/VOCs和SOA/VOCs计)分别为(3.09±0.94)g·g^-1和(2.58±1.99)g·g^-1,苯系物和内全涂烘干工序为O₃和SOA的主要前体物和首要生成节点.     

废弃塑料包装物的管理及资源、环境评价

由于塑料包装材料具有明显的资源优势,而获得广泛应用。但塑料材料的原料——石油,目前面临枯竭窘境。同时,塑料包装废弃物的处理存在巨大的环境压力。焚烧包括塑料包装废弃物在内的生活垃圾,用于发电,是日本曾经采取的方法。近年来,因存在难以逾越的生态环境问题,而逐渐废止。工业生态学的材料流的循环利用模式,是解决资源耗尽、废物充斥的理想方法。源头分离是城市固体废弃物资源化的前提条件。按塑料品种分类回收,以材料形式重复利用,保留了塑料的材料价值,还需要解决,再加工过程造成材料力学性能下降的问题。将单一品种塑料转化成单体,不同塑料品种的单体转化率有很大差距,缩合聚合物较高,而PP、PE等则不然。混合塑料的热裂解可获得化工原料和燃料,又达到减少垃圾总量和石油资源循环利用的效果,具有开发潜力。填埋方式占用土地又人为阻碍了有机垃圾回归生物圈。控制性堆肥对避免大量使用化肥、农药造成的生态环境灾难,再建农业生产的可持续性模式,发挥重要作用。生物降解塑料袋对堆肥的实施,具有特殊价值。PET和E-CO在食品包装某些应用领域有优势,而PVC食品包装物的使用和废弃后再利用都存在问题。     

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。