Mitigation of peroxidative stress for barley exposed to cadmium in the presence of water-extractable organic matter from compost-like materials

The effects of water-extractable organic matter (WEOM) from compost-like materials on peroxidative stress were investigated for hydroponic culture of barley exposed to Cd. In the presence of WEOM, lipoxygenase activity and malondialdehyde, indices of peroxidative stress in barley, were significantly reduced, compared to those with Cd alone (5 μM) for a 30-d culture (p < 0.05). In addition, Cd uptake in the presence of WEOM samples was significantly lower than that in their absence (p < 0.05). These results indicate that the addition of WEOM can be effective in mitigating the peroxidative stress in barley exposed to Cd. Of the total Cd in the solution, 7–8% was complexed with WEOM, indicating that the complexation of Cd with WEOM is a minor factor in reducing Cd-induced stress in barley. The WEOM sample was purified by cation-exchange column and ultrafiltration to remove the nutrient minerals, such as Ca, Mg and Fe. When the purified WEOM was employed for hydroponic culture in the presence of Cd, significant decreases in peroxidative stress and Cd uptake were observed (p < 0.05). These results show that the organic components in WEOM contribute to the mitigation of peroxidative stress in barley exposed to Cd.     

ATIS环境下驾驶员认知负荷研究进展

为构建更加符合驾驶员认知特性的出行信息环境,提高驾驶员出行信息服务水平,对ATIS环境下驾驶员认知负荷研究进展进行系统分析与评述.首先阐述了认知负荷的理论基础,随后分析了ATIS环境下驾驶员认知负荷的影响因素,同时分类解析了驾驶员内在认知负荷、外在认知负荷与相关认知负荷的产生根源,并对认知负荷的形成机理进行了分析;系统评述了驾驶员认知负荷的测量方法,最后基于驾驶员信息认知负荷提出了ATIS优化对策.结果表明:年龄、性别、受教育程度、月收入、出行经验是影响驾驶员认知负荷的主要因素;道路交通标志的版面设计与驾驶员的标志视认时间关联密切;驾驶过程中拨打手机及使用车载终端均会分散驾驶员注意力,增加驾驶员的信息认知负荷;较高的车速与音频播放等环境会对驾驶员的信息认知能力提出更高要求.     

船舶载运煤炭甲烷释放特性研究

为了研究船舶载运煤炭甲烷释放规律,基于Fick扩散定律建立了货舱甲烷体积分数计算模型,分析了不同扩散系数条件下甲烷释放量与时间的关系,确定了空隙系数的取值范围,通过对某船舶煤炭运输过程中甲烷体积分数随船实测对模型进行了验证.结果表明,货舱甲烷体积分数随运输时间增加而增加,扩散系数为1.0×10-8 cm2/s时,甲烷释放量达到极大值;煤炭的空隙系数基本在0.53～ 0.57 m3/t之间.当煤炭极限甲烷解吸量为1.6 ～ 3.83 m3/t时,货舱甲烷最高体积分数在0.53％ ～ 1.22％,5个货舱中4个货舱的甲烷释放量与理论计算相吻合,1个货舱的最大甲烷释放量高出理论计算量6％,船运煤炭过程中的甲烷释放计算模型与实测结果较为吻合.对于甲烷体积分数超限的货舱,及时通风可使甲烷体积分数迅速降低,有效地解决船运煤炭过程中甲烷体积分数超限的问题.     

Climate change,adaptation and Eco-Art in Singapore

Eco-Art has recently emerged as a potential means to place emphasis on environmental issues such as climate change, recycling and the metabolism of the city experienced both materially and conceptually within local, regional and global contexts. Such art presents the possibility of shaping civic practices in arenas beyond those of traditional planning domains. Adopting a pragmatic approach, which recognises the contextual pluralism that exists in debates regarding climate change, this paper is interested in how Eco-Art projects encourage the re-imagining of urban spaces within the context of sustainability, and flows of materials and the recycling of plastic in art specifically.     

危险品运输网络优化设计研究综述

为分析当今反恐新形势下的危险品运输网络优化设计问题的研究现状,系统总结国内外关于一般场景和恐怖袭击威胁2种情况下危险品运输网络优化设计研究的主要模型和方法,梳理两者现有的研究内容,并讨论其共性及恐怖袭击威胁情景下的研究的新特点。结果发现:目前关于解决危险品运输网络优化设计问题模型的鲁棒性研究较为缺乏,尤其是模型在更为复杂和不确定性更强的恐怖袭击情景中适用性不强;危险品运输的鲁棒优化模型即使在突发事件条件下,也可以使决策者能够作出相对满意的决策;鲁棒性危险品运输网络能够规避风险扰动,可用来防止在恐怖袭击中因危险品车辆爆炸等造成更大的危害。     

石墨烯材料去除重金属及放射性核素的研究

石墨烯及其改性材料具有比表面积大、吸附能力强、抗辐射性能好、耐高温、耐酸碱等优点,近年来在去除重金属和放射性核素领域得到了广泛关注.本文简要介绍了石墨烯的合成及改性方法,综述了石墨烯材料去除水中重金属离子和放射性核素的研究进展,包括吸附容量、影响因素、吸附动力学、吸附热力学模型和吸附机理,分析了该研究领域目前存在的问题,探讨了今后的研究方向.     

Immobilization of lead in anthropogenic contaminated soils using phosphates with/without oxalic acid

Understanding the effects of oxalic acid(OA) on the immobilization of Pb(Ⅱ) in contaminated soils by phosphate materials, has considerable benefits for risk assessment and remediation strategies for the soil. A series of phosphate amendments with/without oxalic acid were applied to two anthropogenic contaminated soils. We investigated the immobilization of Pb(Ⅱ) by KH2PO4, phosphate rock(PR), activated phosphate rock(APR) and synthetic hydroxyapatite(HAP) at different phosphate:Pb(P:Pb) molar ratios(0, 0.6, 2.0 and 4.0) in the presence/absence of 50 mmol oxalic acid/kg soil, respectively. The effects of treatments were evaluated using single extraction with deionized water or Ca Cl2, Community Bureau of Reference(BCR) sequential extraction and toxicity characteristic leaching procedure(TCLP)methods. Our results showed that the concentration of water extractable, exchangeable and TCLP-Pb all decreased with incubation time. The concentration of water-extractable Pb after120 days was reduced by 100% when soils were amended with APR, HAP and HAP + OA, and the TCLP-Pb was 5 mg/L for the red soil at P:Pb molar ratio 4.0. Water-soluble Pb could not be detected and the TCLP-Pb was 5 mg/L at all treatments applied to the yellow-brown soil. BCR results indicated that APR was most effective, although a slight enhancement of water-soluble phosphate was detected at the P:Pb molar ratio 4.0 at the beginning of incubation. Oxalic acid activated phosphates, and so mixing insoluble phosphates with oxalic acid may be a useful strategy to improve their effectiveness in reducing Pb bioavailability.     

Multi-objective transportation route optimization for hazardous materials based on GIS

Safety and security are of paramount importance, it is important to optimize and improve the routes of trucks that carry hazardous materials. In this study, we not only ensure the risk in the network, but also consider the transportation cost and the factors such as buildings and emergency facilities around the routes. The Geographic Information System (GIS) is used to quantify the factors on each section in the network. We present an epsilon constrained multi-objective mixed-integer linear programming optimization model to find the robust and stable transportation optimization solutions. At the end, we complete a case analysis of the proposed methodology to determine the motorway segments in Jiangsu province, China and test the above algorithm on the network, which has 144 nodes and 388 sections. The results we get show that the factors of buildings play a very important role in the model, and the multi-objective mixed-integer linear optimization model is reasonable and performs good quality.     

An Interpretive Study of Yosemite National Park Visitors’ Perspectives Toward Alternative Transportation in Yosemite Valley

The National Park Service (NPS) is increasingly focusing on alternative transportation systems in national parks to address environmental and social problems arising from a historical reliance on personal automobiles as the primary means of visitor access. Despite the potential advantages, alternative transportation may require a reorientation in the way that Americans have experienced national parks since the advent of auto-tourism in the early twentieth century. Little research exists, however, on visitor perspectives towards alternative transportation or the rationale underlying their perspectives. It remains unclear how transportation systems affect visitors’ experiences of the park landscape or the factors influencing their travel behavior in the parks. This report presents an interpretive study of visitor perspectives toward transportation management in the Yosemite Valley area of Yosemite National Park, California. Qualitative analysis of 160 semi-structured interviews identified individual psychological factors as well as situational influences that affect visitors’ behavior and perspectives. Individual psychological factors include perceived freedom, environmental values and beliefs, prior experience with Yosemite National Park and other national parks, prior experience with alternative transportation in national parks, and sensitivity to subjective perceptions of crowding. Situational factors included convenience, access, and flexibility of travel modes, as well as type of visit, type of group, and park use level. Interpretive communication designed to encourage voluntary visitor use of alternative transportation should focus on these psychological and situational factors. Although challenges remain, the results of this study suggest approaches for shaping the way Americans visit and experience their national parks to encourage environmental sustainability.     

机器学习在材料服役性能预测中的应用

针对材料服役性能预测存在误差大、计算复杂、适用性差等问题,提出了基于数据挖掘的机器学习预测方法。首先阐述了机器学习的应用流程,并总结了常用模型原理及其在材料性能预测中的应用。然后采用多种机器学习模型对RPV钢的辐照性能进行预测,并通过Stacking集成方法提高了模型的预测精度。结果表明,机器学习可用于材料服役性能预测,具有较高的预测精度和可靠性。根据材料服役数据的不同特征选择合适的学习模型,同时进行模型融合和参数优化,可有效提高模型的预测精度及运算速度。