GB/T28288-2012国家标准中防刺穿垫的技术要求和测试方法

本文系统阐述了GB/T 28288-2012国家标准中防刺穿垫的技术要求、检测设备的主要技术参数、检测方法和质量判定,以及不同标准对同一技术要求出现不一致时的说明,为生产企业产品质量改进和使用企业产品选用提供指导。     

埋地聚乙烯燃气管道基于失效模式的全面检验关键技术及工程应用

PE管道固有较高的性价比,广泛应用在能源、燃气等工程中,但因其焊接接头质量难以检测、位置探查难度大,使PE管道的安全状况难以控制,导致泄漏等事故。基于PE管材的失效模式,参照钢质管道的检验经验,中国特种设备检测研究院研究确定了PE管道基于失效模式的全面检验关键技术,并围绕关键技术开展了多项研究,取得了一系列科研成果,如：PE管焊接质量超声相控阵动态聚焦和B扫查成像检测、探地雷达、泄漏在线检测、老化及安全评价、风险评估方法等。这些系列成果,在新疆、青海、内蒙古、宁夏等城市PE燃气管网中得到了有效应用,检验出多项安全隐患,为城市燃气的安全提供了保障,为今后全面开展PE管线检验,提供了成功经验。     

国外油气管道安全管理经验及启示

近年来,我国油气管道发展迅猛,管道数量激增;上世纪70!80年代修建的管道逐渐进入老龄化,管道事故呈上升趋势。文章对美国、加拿大和欧盟国家油气管道的发展现状和事故情况进行了介绍,重点对以美国为代表的国外油气管道安全管理先进经验进行了分析,并针对当前我国油气管道安全管理的形势和问题,提出了一些建议。     

Herbivore species, infestation time, and herbivore density affect induced volatiles in tea plants

In response to insect herbivory, plants emit volatiles that are used by the herbivores’ natural enemies to locate their host or prey. Herbivore attack also enhances tea aroma. Herbivore-induced plant volatiles (HIPVs) vary both quantitatively and qualitatively with infestation duration and herbivore density. Thus, whether HIPVs can reliably communicate the identities of herbivores is of interest. Here, we studied the tea plant volatiles induced by the tea leafhopper (Empoasca vitis, a piercing–sucking insect), the tea geometrid (Ectropis oblique, a chewing insect), and methyl jasmonate (MeJA, a plant hormone). Geometrid feeding induced more complex volatile blends than did leafhopper infestation. The volatiles induced by both herbivores significantly increased in quality and quantity with time during the first 16 h of infestation, after which the profiles of induced volatile blends and the emission of induced compounds varied diurnally. (E)-β-Ocimene displayed a unique rhythm in which emission peaked at night. The amount of HIPVs significantly increased, while their profiles changed little, with herbivore density. Overall, the leafhoppers and geometrids induced significantly different volatiles from tea plants, while the HIPV profiles varied with a circadian rhythm and were similar at different herbivore densities. Our findings also suggest a new method of enhancing tea flavor using exogenously applied plant hormones, because the volatiles induced by leafhoppers and MeJA were similar in general composition.     

土壤中铜的生物可给性及其对人体的健康风险评价

为了研究土壤中铜的生物可给性与土壤理化性质之间的相互关系以及人体无意摄入土壤铜的风险,采集我国一些地区的15个土壤样品,利用in vitro方法研究了这些土壤中铜的生物可给性及其对人体的健康风险。结果表明,有2个土壤样品中铜的含量高过我国土壤环境质量标准的三级标准,有8个土壤样品中铜的含量高过二级标准;土壤中铜的溶解态浓度及其生物可给性变化很大,胃肠阶段铜的溶解态含量分别为5.2~308.8 mg·kg~(-1)和5.9~348.5 mg·kg~(-1),平均值分别为74.8 mg·kg~(-1)和82.0 mg·kg~(-1);而铜的生物可给性分别为183%~66.6%和213%~77.4%,平均值分别为442%和51.1%。胃阶段铜的生物可给性与土壤有机质和pH呈显著正相关,而与粘粒呈显著负相关,与铁铝氧化物有显著相关性;小肠阶段铜的生物可给性与土壤有机质和pH呈显著正相关,与土壤中总铜和锰氧化物含量呈显著负相关。如以胃阶段为判断,无意摄人土壤中铜对儿童的TDI(tolerable daily intake)贡献率除浙江富阳为2.51%外,有12个土壤样品低于1.00%,最低为0.11%。如以小肠阶段为判断,无意摄入土壤中铜对儿童的TDI贡献率除浙江富阳和浙江台州的土壤分别为2.83%和2.01%,另有12个土壤样品低于1.00%。可见,对于本研究中大多数土壤,通过口部无意摄入土壤中铜的对人体并没有很高的风险。     

Improvement of nitrification efficiency by bioaugmentation in sequencing batch reactors at low temperature

Bioaugmentation is an effective method of treating municipal wastewater with high ammonia concentration in sequencing batch reactors （SBRs） at low temperature （10℃）. The cold-adapted ammonia- and nitrite- oxidizing bacteria were enriched and inoculated, respectively, in the bioaugmentation systems. In synthetic wastewater treatment systems, the average NH4＋-N removal efficiency in the bioaugmented system （85%） was much higher than that in the unbioaugmented system. The effluent NH4＋ -N concentration of the bioaugmented system was stably below 8 mg. L1 after 20 d operation. In municipal wastewater systems with bioaugmentation, the effluent NH4＋- -N concentration was below 8 mg·L^-1 after 15 d operation. The average NH4＋ -N removal efficiency in unbioaugmentation system （about 82%） was lower compared with that in the bioaugmentation system. By inoculating the cold-adapted nitrite-oxidizing bacteria （NOB） into the SBRs after 10 d operation, the nitrite concentration decreased rapidly, reducing the NO2 -N accumulation effectively at low temperature. The func- tional microorganisms were identified by PCR-DGGE, including uncultured Dechloromonas sp., uncultured Nitrospira sp., Clostridium sp. and uncultured Thauera sp. The results suggested that the cold-adapted microbial agent of ammonia-oxidizing bacteria （AOB） and NOB could accelerate the start-up and promote achieving the stable operation of the low-temperature SBRs for nitrification.     

絮凝沉淀法处理电解金属锰废水的研究

采用絮凝沉淀法处理电解金属锰废水,主要研究水力条件、最佳混凝剂、助凝剂投加量对处理效果的影响。实验结果表明:最佳混凝剂组为聚合氯化铝-聚丙烯酰胺,其最佳投加量分别为:聚合氯化铝为90 mg/L,聚丙烯酰胺为50 mg/L。当pH=9.0时,采用先无机再有机的投加混凝剂的顺序,水力条件工艺控制为先加无机混凝剂慢速搅拌1 min,再加有机助凝剂快速搅拌2 min,效果为最佳。     

不同曝气能耗对水蚯蚓原位消解污泥的影响

水蚯蚓原位消解污泥过程中,曝气参数的设定十分重要。为评价曝气能耗对水蚯蚓消解污泥的影响并设定适宜的曝气量,研究污水处理系统耦合水蚯蚓后不同曝气梯度下的运行情况,并对耦合水蚯蚓前后的系统进行比较。结果表明:溶解氧最适范围为2～3 mg/L,曝气能耗约为0.19 kW.h/t;溶解氧高于3 mg/L时系统能效并无提高,且能耗增大。     

Assessment of opium-based farming systems: a case study in the Nahom area,Oudomxay Province in Northern Laos

SUMMARY

An interdisciplinary team of 10 completed an exploratory one-month survey of villages in Nahom, Oudomxay Province, Laos, an area representative of upland farming systems based on opium and shifting cultivation. The study included investigation of the physical and socioeconomic environments and assessment of the farming systems. Due to the relatively low population density, there is enough land for villagers to practice shifting cultivation with a one year cultivation cycle, followed by 10–12 years of fallow. The soil degradation commonly caused by shifting cultivation was not significant in this area and the soil fertility is still relatively high. However, most of the original forests had been cut down and used for shifting cultivation and some degradation of the vegetation has occurred, showing that the ecological sustainability has been threatened by prevailing practices. Thirty-six percent of the households had food supply problems for more than three months of each year. The extremely low return for labour from upland rice cultivation, only 5.64 kg per labour-day, was the critical factor that caused the food shortage. Because of poor technique, rice yield from paddy fields was also low, thus shifting cultivators have no enthusiasm to expand their paddy fields. Income from opium provided 80.5% of household income. Opium was extremely tempting to local people due to the very high return for labour, 5700 kip (US$6) per labour-day, low investment, and good labour availability (mostly during the off-season of rice cultivation). However, opium was also a ‘two-edged sword’. It did not bring real wealth, health and happiness but instead brings poverty, poor health and disappointment.     

Response of bacterial communities to short-term pyrene exposure in red soil

Pyrene, a representative polycyclic aromatic hydrocarbon (PAH) compound produced mainly from incomplete combustion of fossil fuels, is hazardous to ecosystem health. However, long-term exposure studies did not detect any significant effects of pyrene on soil microorganism. In this study, short-term microcosm experiments were conducted to identify the immediate effect of pyrene on soil bacterial communities. A freshly-collected pristine red soil was spiked with pyrene at 0, 10, 100, 200, and 500 mg·kg^-1 and incubated for one day and seven days. The bacterial communities in the incubated soils were analyzed using 16S rRNA sequencing and terminal restriction fragment length polymorphism (T-RFLP) methods. The results revealed high bacterial diversity in both unspiked and pyrene-spiked soils. Only at the highest pyrene-spiking rate of 500 mg·kg^-1, two minor bacteria groups of the identified 14 most abundant bacteria groups were completely suppressed. Short-term exposure to pyrene resulted in dominance of Proteobacteria in soil, followed by Acidobacteria, Firmutes, and Bacteroidetes. Our findings showed that bacterial community structure did respond to the presence of pyrene but recovered rapidly from the perturbation. The intensity of impact and the rate of recovery showed some pyrene dosage-dependent trends. Our results revealed that different levels of pyrene may affect the bacterial community structure by suppressing or selecting certain groups of bacteria. It was also found that the bacterial community was most susceptible to pyrene within one day of the chemical addition.