城区大气和塑料大棚空气中酞酸酯的分析

本文报道了济南市大气飘尘和塑料蔬菜大棚空气中酞酸酯的污染情况，探讨了大气飘尘中酞酸酯随季节变化和昼夜更替的变化情况。     

塑料给水管材的选用分析

给水工程中如何根据不同的场合选用合适的塑料给水管材,本文从可靠性、使用寿命和工程造价等方面进行了阐述.     

Crop Failure in Dalocha, Ethiopia: A Participatory Emergency Response

This case study of an NGO's response to a food crisis due to crop failure focuses on the extent of active community participation at each stage of the project. With the current debate on the relationship between relief and development, and in particular the focus on encouraging more active community participation in relief responses, this study has relevance both in the Ethiopian context and beyond.
In this example the participation process was greatly facilitated by the prior relationship between the international NGO and the communities, and also by the high level of staff input into the project. Where resources or conditions are less favourable, as might be the case in similar responses by local NGOs or government agencies, the paper suggests that the participatory approach can be adapted or partially implemented and still result in a more effective and locally relevant operation.     

Biodegradation of Injection Molded Starch-Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) Blends in a Natural Compost Environment

Injection molded specimens were prepared by blending poly (hydroxybutyrate-co-valerate) (PHBV) with cornstarch. Blended formulations incorporated 30% or 50% starch in the presence or absence of poly-(ethylene oxide) (PEO), which enhances the adherence of starch granules to PHBV. These formulations were evaluated for their biodegradability in natural compost by measuring changes in physical and chemical properties over a period of 125 days. The degradation of plastic material, as evidenced by weight loss and deterioration in tensile properties, correlated with the amount of starch present in the blends (neat PHBV < 30% starch < 50% starch). Incorporation of PEO into starch-PHBV blends had little or no effect on the rate of weight loss. Starch in blends degraded faster than PHBV and it accelerated PHBV degradation. Also, PHBV did not retard starch degradation. After 125 days of exposure to compost, neat PHBV lost 7% of its weight (0.056% weight loss/day), while the PHBV component of a 50% starch blend lost 41% of its weight (0.328% weight loss/day). PHB and PHV moieties within the copolymer degraded at similar rates, regardless of the presence of starch, as determined by ¹H-NMR spectroscopy. GPC analyses revealed that, while the number average molecular weight (Mn) of PHBV in all exposed samples decreased, there was no significant difference in this decrease between neat PHBV as opposed to PHBV blended with starch. SEM showed homogeneously distributed starch granules embedded in a PHBV matrix, typical of a filler material. Starch granules were rapidly depleted during exposure to compost, increasing the surface area of the PHBV matrix.     

Tired of innovations? Learned helplessness and fatigue in the context of continuous streams of innovation implementation

The business environment faced by contemporary organizations is highly uncertain and constantly changing. Thus, organizations have adopted and implemented a continuous stream of innovations to achieve sustainable growth and survival. Considering the demand for additional resources to implement innovations, the present study explores organizational conditions that may lead to innovation‐targeted burnout and fatigue among employees, which impede their active participation in a subsequent innovation. To this end, we propose a theoretical framework that elucidates the effects of previous innovations on the subsequent implementation behavior of employees. We identify two dimensions of the cognitive appraisal of previous innovations (i.e., intensity and failure) that shape employees' beliefs regarding innovations, such as innovation‐targeted helplessness, which ultimately results in innovation fatigue. Data collected from 84 managers and 397 employees of Chinese and Korean organizations prove the significant role of employee perceptions of previous innovations in shaping the innovation‐targeted helplessness and fatigue of employees, which ultimately affect employee behavior toward a subsequent innovation. The present conceptual and empirical analyses suggest that given continuous streams of innovation implementation, managers should carefully consider employee's perceptions of previous innovations (i.e., intensity and failure) for successful implementation of a subsequent innovation. Copyright © 2017 John Wiley & Sons, Ltd.     

基于GM(1,1)的残差修正模型的电梯故障率预测

为研究某城市某品牌电梯故障率发展趋势,建立了该城市该品牌电梯故障率的GM(1,1)灰色预测模型,并对所建模型进行了数据检验,检验结果表明该预测模型的预测精度波动较大。为了提高GM(1,1)灰色预测模型的预测精度,利用对模型进行数据检验时得到的残差序列,建立GM(1,1)灰色预测模型的残差修正模型,利用该残差修正模型对原预测模型进行修正。利用经残差修正模型修正后的故障率预测模型对该城市A品牌电梯的故障率进行预测,结果表明:1)残差修正模型对原模型修正后的相对误差与修正前相比有升也有降,但精度有所提高且趋于稳定,表明残差修正模型有利于提高预测精度;2)利用所建立的故障率预测模型求得的预测故障率与实际故障率相比,相对误差不超过8.010%,表明该故障率预测模型的预测精度较高;3)修正模型预测值表明,在现有状态下该城市A品牌电梯的故障率呈上升趋势,应加强该品牌电梯的检维修与管理。     

基于POF的温度应力加速试验失效机理一致性研究

目的通过失效物理手段得到温度加速寿命试验的失效机理突变点,节省试验样本,并为加速寿命试验的有效性提供保障。方法利用电子产品典型失效物理模型,在求解MOSFET器件激活能的基础上确定失效机理突变点,并开展失效物理分析,从微观分析的角度验证失效机理一致性判定方法的理论正确性和工程适用性。结果 MOSFET器件在温度低于240℃时,失效机理没有发生改变;温度高于240℃时,失效机理发生了改变,与前述失效机理不一致。结论基于失效物理的方法可以确定器件机理发生变化的温度应力点,所需样本量小。     

塑料玩具中邻苯二甲酸酯类环境激素检测方法研究

文章建立了一种对塑料玩具中5种邻苯二甲酸酯类物质同时分离和检测的高效液相色谱分析法。以shim-pack VP-ODS(4.6mm×150mm,5μm)为分离柱;以甲醇-水(体积比:90:10)为流动相,流速:1.0mL/min,检测波长:230nm。该方法所测得的5种邻苯二甲酸酯类物质在0.5～1000mg/L内具有良好的线性,相关系数r=0.9996,检出限达0.34～0.96μg/L,平均回收率在93.00%～105.23%。在对样品提取和纯化的基础上,对塑料玩具中邻苯二甲酸酯类物质进行了分析,结果令人满意。     

喷淋工艺处理PVC塑料生产废气

采用喷淋工艺处理PVC塑料生产废气,将专利的吸收液与改型的喷淋塔相结合,在中试成功的基础上进行了实际工业化应用。应用结果表明:采用该工艺处理某PVC塑料生产企业的生产废气,吸收液在喷淋塔循环液中所占体积分数为15%时,废气中各污染物指标的去除率达85%以上,对于难处理的苯系物也能较好地去除;处理后废气中各污染物指标的含量满足GB 14554—1993《恶臭污染物排放标准》和DB 44/27—2001《大气污染物排放限值》的要求;该工艺装置运行费用较低,仅为电费和少量药剂费用,吸收液可循环使用,设备保养及维护简单,可满足市场需求。     

军用风力发电机紧固螺栓断裂失效分析

目的研究风力发电机紧固螺栓断裂失效原因。方法通过化学成分分析、力学性能分析、断口扫描分析、显微组织分析测试手段,对风力发电机紧固螺栓失效原因进行分析。结果断裂螺栓螺纹根部表面存在原始折叠缺陷,为疲劳裂纹的萌生提供了有利条件;同时,螺栓头部、紧固垫圈及法兰盘之间存在装配异常情况,外力作用下接触位置应力集中较大,有利于疲劳裂纹的萌生及进一步扩展。结论通过严格控制入厂螺栓质量,同时定期检查在服役螺栓的使用状态,及时更换存在安全隐患的螺栓,有效杜绝了紧固螺栓断裂失效情况再次发生。