Palladium nanoparticles supported on amine-functionalized glass fiber mat for fixed-bed reactors on the effective removal of hexavalent chromium by catalytic reduction

Palladium nanoparticles were deposited on the amine-grafted glass fiber mat (GFM-NH₂) catalyst support by a conventional impregnation process followed by the borohydride reduction in aqueous solution at room temperature to create the designed Pd/GFM-NH₂ catalyst. By the use of large size glass fiber mat without nano/mesopores as the catalyst support, the internal mass transfer limitations due to the existence of nano/mesopores on the catalyst support were eliminated and the Pd/GFM-NH₂ catalyst could be easily separated from treated water due to the large size of the catalyst support. Batch experiments demonstrate its good catalytic reduction performance of Cr(VI) with formic acid as the reducing agent. It also demonstrated an efficient Cr(VI) removal and stability in a lab-prepared, packed fixed-bed tube reactor for the continuous treatment of Cr(VI)-containing water. Thus, it has a good potential for the catalytic reduction of Cr(VI) in the water treatment practice.     

Development of predictive models for the estimation of the probability of suffering fear of falling and other fall risk factors based on posturography parameters in community-dwelling older adults

Falls pose an important problem for older adults. Balance training is one of the main prevention strategies, but there is a lack of objective measurement methods that would allow the effectiveness of the treatments employed to be assessed. This study aimed to analyse the relationship between posturographic parameters and risk factors associated with falling, including the fear of falling (FoF). Forty-one healthy community-dwelling older adults were surveyed on their perception of problems considered to be fall risk factors. Balance measurement with posturography was performed. The relationships between risk factors and falls and risk factors and posturography were analysed by means of cross-tabulation and logistic regression, respectively. Experimental results showed a significant relationship between some of the posturographic parameters and various fall risk factors. Stability limits were related to FoF, and results from the Romberg test with eyes closed with and without foam correlated with problems in kneeling/crouching. The results from the Romberg test with eyes closed and foam correlated with osteoarthritis. Equations were developed to estimate the probability of having such problems. In conclusion, posturography is useful for the estimation of fall risk conditions in relation to three important fall risk factors (FoF, osteoarthritis and problems in kneeling/crouching), and it could be used for targeting, training and studying progress after the use of different treatments.Relevance to industryPosturography can be used as an assessment tool to analyse the effects of those treatments aimed at preventing falls. Furthermore, the equations derived from our results can be used along with posturographic variables to assess patient progress.     

Declining phosphorus as a potential driver for the onset of Didymosphenia geminata mats in North American rivers

Didymosphenia geminata is a stalk‐forming diatom capable of creating thick benthic mats in low‐nutrient streams. There are two hypotheses to explain the rapid worldwide increase in occurrence of nuisance D. geminata mats: (a) Cells are spread among rivers and across broad ecoregions through natural and anthropogenic vectors, or (2) pre‐existing D. geminata populations are forming mats in response to changing environmental conditions within the habitat. Low phosphorus (P) concentrations are a major trigger for stalk production by D. geminata cells. Although the environmental change hypothesis is gaining support among researchers, long‐term data sets demonstrating declining P concentrations prior to reported mat formation have been essentially absent from the literature. Here, we present long‐term datasets for two case studies for which long‐term P and D. geminata data coincide: the Matapedia River in Eastern Canada and the Kootenai River below Libby Dam in Montana, United States. Both rivers had declining P levels over time. However, there was a 2‐ and 20‐year lag time, respectively, between mat development and reaching the previously proposed average 2 μg/L soluble reactive P threshold for development. Although the Matapedia River provides some support of the environmental change hypothesis, the Kootenai River data set suggests other environmental factors may play a role in mat development. The data presented do not rule out the environmental change hypothesis but do suggest there may be conditions in addition to low P that must be met for mats to form and the environmental change hypothesis can likely be refined to include more parameters to better understand and mitigate the influence of mats.     

高速明渠流条件下高性能加筋草皮抗侵蚀特性研究

现有针对高性能加筋草皮的抗侵蚀性能研究,大多建立在大规模试验基础上,重点研究允许冲刷流速和表面切应力。为了研究高速明渠水流条件下高性能加筋草皮侵蚀过程,对天然草皮和3种高性能加筋草皮共48个样品进行培植,并布置在高速明渠流的倾斜水槽中,通过不同坡度和流量分别进行间断和不间断冲刷试验,分析流速、流量和侵蚀量的关系。结果表明,间断和不间断冲刷的侵蚀速率有明显差异,说明初始冲刷引起了高性能加筋草皮的大部分侵蚀。样本侵蚀过程显示侵蚀速率随侵蚀量的增加而降低,证明明渠高速水流作用下加筋草皮存在“侵蚀上限”特征。此外,还讨论了流量和生态加筋网结构对侵蚀过程的影响,并尝试拟合了平均侵蚀速率与水流表面流速的关系。     

生态护坡在辽宁省城市河道整治中的应用

简述了传统护坡治理中存在的问题,介绍了生态袋护坡、三维植被网护坡及稻草垫生物护坡在辽宁省河道治理中的应用,结合工程实例阐述了三种护坡形式的特点及实际应用中应注意的问题。     

玻纤毡增强聚丙烯复合材料的增容及力学性能

通过玻璃纤维(GF)毡与双螺杆挤出相容剂改性聚丙烯(PP)膜的多层叠合,以熔融浸渍法制得PP基GF毡增强热塑性塑料(GMT)复合材料,研究了相容剂PP接枝马来酸酐(PP-g-MAH)和PP接枝丙烯酸(PP-g-AA)的用量(为PP基体质量的百分数)及其复配改性,以及相容剂改性PP基体分布和毡体种类对GMT力学性能的影响。结果表明,PPg-MAH可明显提高GMT的拉伸与弯曲性能,但降低了冲击性能;PP-g-AA可明显提高GMT的冲击性能,但不利于拉伸与弯曲性能的提高,只有当PP-g-AA用量超过5%后,拉伸性能才有所提升。在PP-g-MAH用量为3%的条件下,将其与不同用量的PP-g-AA进行复配改性没有对GMT力学性能产生协同作用。在各相容剂用量相近(3%~3.5%)的情况下,与相容剂复配改性GMT相比,以两层PP-g-AA改性PP为芯层、PP-g-MAH改性PP为上下表面层作为改性基体分布时,GMT拉伸与弯曲强度分别提高17%和27%、缺口冲击强度提高48%;而以两层PP-g-MAH改性PP为芯层、PP-g-AA改性PP为上下表面层作为改性基体分布时,在不损失强度与刚性的同时,缺口冲击强度提高了88%。采用连续GF毡的GMT力学性能比采用短切GF毡的GMT高,尤其是缺口冲击强度提高了89.6%。     

水下崩岸段吨袋垫坡与膜袋自密实混凝土护坡施工技术应用与效果分析

河道的回水地带常年受河道水流迎流顶冲影响,岸坡冲刷严重易崩塌,影响岸坡安全。以涡河县义门镇涡河左堤崩岸段应急加固工程为例,采用吨袋垫坡+膜袋自密实混凝土护坡技术对崩岸段进行加固处理有效解决了水下护岸边坡因水流冲刷引起的变形与坍塌问题,效果良好,可为类似工程施工提供参考。     

低成本一次低温快烧生料无光釉的研制

以工业废渣为主要原料研制了低温一次快烧生料无光釉，分析探讨了废渣无光釉的化学组成和烧成条件，该釉不仅适于一次低温快烧工艺，而且可显著降低釉料成本，在墙地砖生产中有较大应用价值。     

一种全局指数收敛的摄像机内参数观测器

针对摄像机标定问题,本文从控制理论角度出发设计了一种具有指数收敛特性的摄像机内参数观测器.当摄像机随移动机器人等运动平台一起旋转时,该观测器使用其运动信息和实时拍摄得到的特征点图像信息,可以实现对摄像机内参数的在线估计.具体而言,论文分析了云台摄像机的运动约束,建立了特征点图像坐标变化的运动学模型,随后基于4个或4个以上特征点（其中任意3点不共线）,构造了一种内参数非线性观测器,并通过理论分析证明了其状态估计指数收敛于摄像机的相应内参数,仿真结果验证了这种非线性观测器的良好特性.     

模型试验分析建筑物混凝土基础底板开裂

分析了建筑物混凝土基础底板的主要开裂原因，研究了试验模型和试验方法。通过实际工程天都花园建筑混凝土基础底板的开裂情况，利用相似原理建立开裂分析试验模型，模拟基础底板的温度场和约束条件，研究分析底板开裂。根据试验结果，分析讨论了混凝土底板的裂缝，得出相应结论以及对实际工程的意义。