Vibration of Three-Layered FGM Cylindrical Shells with Middle Layer of Isotropic Material for Various Boundary Conditions

In the present study, vibration analysis of a three-layered cylindrical shell is performed whose inner and outer layers are composed of functionally graded materials whereas the middle one is assumed to be of isotropic material. This formation of a cylindrical shell influences stiffness modulii and the resultant material properties. The shell problem is formulated from the constitutive relations of stresses and strains with the displacement deformations and they are taken from Love’s thin shell theory. This problem is transformed into the integral form by evaluating the expressions for the strain and kinetic energies of the shell. Rayleigh-Ritz method is employed to solve the shell dynamic equations. Vibration characteristics of these cylindrical shells are investigated for a number of physical parameters and configurations of the fabrication of shells. The axial modal dependence is approximated by the characteristic beam functions that satisfy the boundary conditions. Results evaluated, show good agreement with the open literature.

Clean Steel Technologies Based on Interactions of Refractory Filtering Materials with Steel Melt

New carbon bonded filters with “active and reactive coatings ” for higher filtration efficiency of alumina based inclusions as well as nano-engineered filters with nano-scaled additives are explored with the aid of impingement tests and are evaluated according to their cold crushing strengths at room temperature. The combination of carbon nanotubes and alumina nanosheets additives leads to in situ formation of Al3 CON. Both the nanoscaled additives as well as the extra alumina “active”coating lead to improved mechanical performance of the carbon bonded filters and open the horizon for filter macrostructures with higher filtration capacities in means of bigger dimensions. In a further step MWCNT（ multi walled carbon nanotubes） in combination with a synthetic pitch have been used as a functional coating on the surface of alumina carbon bonded filters. These filters have then been evaluated also with uncoated filters in a special casting simulator and the interactions between steel and filtering material have been investigated.

Performance of Nonwoven Filter Materials Based on the Operating Condition

The practical condition of needle-punched filters applied in coal-fired power plants is investigated. According to the actual operating conditions, two common filters (glass fiber filter and polyphenylene sulfide (PPS) filter) are selected for experiment. The performance of these two kinds of filter is compared based on a series of tests such as resistance to the acid and alkali, oxidation resistance,hydrolysis resistance,and wear resistance. Experimental results show that PPS filter materials have better properties than those of glass filter material except oxidation resistance. Composite filter mixed glass fiber and PPS is recommended for polluters because of its good properties in all aspects.

Efficiency characterization of ceramic filtering materials used for drinking water treatment

For ceramic filtering materials, their adsorption capacities, purification efficiencies to remove organic compounds from drinking water, and correlation between adsorption capacities and pore structures were tested and analyzed. The results show that correlation coefficient between the specific surface area and the adsorptive amount of iodine molecule is 0.99; correlation coefficient between the pore volume and the adsorptive value of tannin molecule is 0.92, and correlation coefficient between the most probable diameter and the adsorption parameter is 1.0. A new method of morphology characterization for ceramic filtering materials was developed, which offered a sort of standard for the evaluation on water purification efficiencies and selection of ceramic filtering materials.

基于改进Filter和随机森林的应急物资供应商评价方法研究

针对应急物资供应商评价时因主观因素影响较大、存在冗余指标等情况,导致供应商评价分类效果不佳的问题,提出基于改进Filter和随机森林的方法改善应急物资供应商评价分类预测效果的思路。利用Filter中拉普拉斯分值算法的高效计算能力进行初步特征优化,并在此过程中引入互信息法消除冗余特征,构建随机森林分类器,以期在消除主观因素影响的同时,降低冗余指标造成的不利后果。实验数据显示,该方法可以明显提升应急物资供应商评价时的分类预测效果,为应急供应链管理的快速构建和高效运作提供可靠依据。

THE STUDY OF THE FILTRATION EFFICIENCY OF FILTER MATERIAL

In this paper, the course of the filtration is analyzed.In order to study the filtration efficiency of the filter material, the computer program was edited.According to the results of the computer program, some important parameters of the filter material are discussed.It shows that the filtration efficiency is closely related to the diameter (d) and the size (b) .In addition, by using these results and the computer program, we can analysis the relationship between the fiber structure and filter properties quantitatively.

Treatment of tunnel wash waters-experiments with organic sorbent materials.PartⅠ:Removal of polycyclic aromatic hydrocarbons and nonpolar oil

Tunnel wash waters characterize all waters that run off after washing procedures of tunnels are performed.These waters represent a wide spectrum of organic and inorganic pollutants,such as polycyclic aromatic hydrocarbons(PAHs)and toxic metals.Removal of such contaminants from water runoff was investigated using laboratory tests after washing procedure was performed on two road tunnels in eastern Norway(Hanekleiv and Bragernes).Due to diverse character of both,treatment media and treated wash waters, the wh...

Transmission properties of fractal Cantor distribution with left-handed materials

Transmission properties of fractal Cantor distribution with left-handed materials （LHM） are investigated. The transmittance and reflectance spectra can be calculated by using the optical transmission matrix method. Comparing with the conventional Cantor multilayers, these structures with LHM have double functions of stopbands and defects. Through adjusting the thickness of dielectric layers, the properties of stopbands and defects can be obtained, respectively. For stopbands, a broad stopband filter is studied. For defect modes, multi-frequencies narrow passband filters are proposed.

铸造过滤网用无机-有机耐热复合涂层材料研究

利用生产热塑性酚醛树脂产生的废水和六羟甲基三聚氰胺(HMM),生产铸造过滤网用耐热涂层材料HMM改性酚醛树脂,并与液体铝溶胶复合,制备过滤网用无机-有机耐热涂层复合材料。借助残炭率的测定、热重分析和差示扫描量法手段,分析了HMM改性酚醛树脂的组成对改性酚醛树脂的耐热性能影响,同时还分析了无机-有机耐热复合涂层材料降低过滤网发烟量与阻止着火机理,以及讨论了影响过滤网性能的因素;从而得出HMM改性酚醛树脂最佳组成为HMM改性酚醛树的固体物中氮含量约在5%左右,无机-有机复合涂层材料的最佳组成为HMM改性酚醛树脂与液体铝溶胶质量比为4∶1,铝溶胶有利于提高过滤网复合涂层材料耐热性能和降低过滤网发烟量、阻止着火有一定作用。

后处理工艺对抗静电滤料性能的影响

选择基布中嵌织导电纱线的基布导电型和面层中混入导电纤维的面层导电型2种典型抗静电滤料作为基材,进行聚四氟乙烯(PTFE)乳液浸渍处理和PTFE微孔膜覆膜处理,得到面密度和厚度均匀的复合滤料。再基于电阻率、静电压衰减时间及摩擦带电电压3项指标,从静电荷的消散及积聚2个角度,探究了后处理工艺对抗静电滤料性能的影响。试验结果表明:浸渍处理后,滤料抗静电性能提升,2种滤料的迎尘面表面电阻率和体积电阻率均降低且降幅小于1个数量级,基布导电型滤料和面层导电型滤料的迎尘面静电压半衰期分别由0.40 s、0.23 s缩短至0.38 s、0.20 s,摩擦时间为60 s时摩擦带电电压分别由1043 V、596 V减小至668 V、67 V。覆膜处理后,滤料抗静电性能下降,基布导电型滤料迎尘面表面电阻率升高且升幅为1个数量级、体积电阻率升高但升幅小于1个数量级,面层导电型滤料迎尘面表面电阻率和体积电阻率均升高且升幅为4个数量级,基布导电型滤料和面层导电型滤料迎尘面静电压半衰期分别由0.40 s、0.23 s延长至0.53 s、0.77 s,摩擦时间为60 s时摩擦带电电压分别由1043 V、596 V增大至1952 V、920 V。

玻璃纤维滤材的疏水改性及过滤性能

闭式循环过程会产生大量放射性气溶胶,其高湿、高酸、高放射性的特点导致基于玻璃纤维滤材的高效过滤器失效快、更换频率高。为解决上述问题,提出对传统的玻璃纤维滤材进行疏水性改性,以提高玻璃纤维滤材对苛刻工况的耐受性。利用低表面能改性剂(聚二甲基硅氧烷)对滤材进行化学性疏水性改性,通过引用SiO_(2)纳米颗粒物进行微结构构造,进一步改善疏水效果。借助SEM、FTIR、接触角测量仪等手段对改性效果进行了分析,并进一步研究了改性滤材的过滤性能。研究结果表明:改性方案能够有效改善玻璃纤维滤材的疏水性,并提高其耐湿性;单纯化学改性滤材的静态接触角可达146°,引入SiO_(2)纳米颗粒物后改性滤材的接触角超过150°;当改性剂中聚二甲基硅氧烷质量分数为2.0%、SiO_(2)纳米颗粒物质量分数为0.5%时,所得GF-PS-0.5滤材展现出最优的耐酸性,主要源于化学性疏水和结构性疏水的有效协同;GF-PS-0.5在经受足量的γ照射后,疏水性保持稳定,表明其良好的耐辐照性;改性滤材仍然保持了优异的过滤性能,其过滤效率超过99.99%。改性过程在提高滤材耐受性的同时,没有影响其过滤性能,展现出良好的应用前景。

微波陶瓷介质滤波器成型烧结工艺可靠性研究

该文从微波陶瓷材料NP37本身出发,压制标准件,通过对密度、电性能测试及内部切片形态观测验证不同成型压力、烧结设备(气氛炉和隧道炉)、烧结温度工艺下对坯体制作性能及可靠性的影响。研究表明,在成型压力2000 kg、隧道炉1160℃烧结工艺下,坯体性能及可靠性测试结果最佳。将其用于介质滤波器的坯体制作、介质滤波器坯体的切片、扫描电镜(SEM)测试、热震试验及温度冲击试验,结果验证了此成型烧结工艺可靠性较高。结果表明,通过验证标准件成型烧结工艺指导介质滤波器生产的方法能有效地提高产品可靠性。

复合改性砂滤料制备及生物砂滤池对受污染原水的净化效果

为改善普通石英砂(QS)表面特性,提高生物砂滤池生物附着量及对水中污染物的去除效果,对QS进行氨基、铝离子及铝钙双氢氧化物改性,制得氨基改性砂(AMS)、铝离子改性砂(ALS)和铝钙双氢氧化物改性砂(CAS),以四种滤料填充滤池考察对受污染原水的净化效果。结果表明,与QS相比,ALS与CAS表面覆盖了金属离子,AMS、ALS、CAS表面形态及比表面积均得到改善,成膜后表面生物附着量分别增加3.6、5.5、6.9 mg/g;滤速为5 m/h时,CAS滤池对浊度和COD平均去除率分别为90.1%、51.8%。与AMS、ALS滤池相比,CAS滤池表面生物量最大,对水中污染物去除效果良好。

操作参数和滤材结构对纤维滤材油-水聚结分离性能的影响

为提高纤维滤材对油-水聚结分离性能,搭建油-水聚结分离性能测试装置,探究含油量和过滤速率协同、纤维滤材层数以及孔径等操作参数和滤材结构对水包油乳液聚结分离性能以及液体分布影响。研究结果表明,单层平均孔径15.1μm聚丙烯纤维滤材在过滤速率0.001 m/s、含油量1000 mg/L的条件下可获得最高80.2%的除油效率、最大0.96的品质因子。当含油量相同时,滤材的饱和度与过滤速率呈反比;过滤速率相同时,滤材的饱和度和含油量呈正比。滤材品质因子随着纤维滤材(平均孔径15.1μm)层数由1层增加到5层,其曲线变化趋势为先增大后减小,除油效率可显著提升23.2%,下游平均粒径降低约80.0%。滤材孔径与滤材效率和品质因子呈反比,在过滤速率0.001 m/s、含油量100 mg/L的条件下,随平均孔径从15.1μm增加到21.6μm,滤材的除油效率从67.1%下降到31.2%,品质因子从0.64下降到0.35。纤维滤材表面液体分布和内部持液量分析表明,油相主要聚集在滤材上半部分,沿流动方向滤材内部可能存在厚薄不均匀的油膜。

非织造空气过滤材料制备及功能化研究进展

总结非织造空气过滤材料制备工艺及功能化改性的研究进展。对针刺、熔喷和静电纺丝等非织造空气过滤材料制备方法进行了阐述,分析了不同非织造工艺技术存在的问题。对非织造空气过滤材料抗菌、除甲醛、脱硝、脱硫和耐高温等功能化改性进行了探讨。认为:通过优化工艺流程、调控织物结构制备绿色高效非织造空气过滤材料是未来发展方向。

3种滤料对池塘圈养尾水处理效果的影响

为了探究过滤材料用于池塘圈养尾水的处理效果,采用火山岩、活性炭及沸石作为过滤材料,以滤料种类、滤料粒径和滤料厚度为试验因素,以总固体悬浮物(total suspended solid,TSS)去除率、氨氮(NH_(4)^(+)-N)去除率和化学需氧量(chemical oxygen demand,COD)去除率为试验指标,开展池塘圈养尾水处理试验。结果显示,3种滤料均能去除池塘圈养尾水中的TSS和COD,均能在一定程度上降低池塘圈养尾水中的NH_(4)^(+)-N浓度,活性炭的处理效果优于其他2种滤料,且活性炭粒径越小或厚度越大时对池塘圈养尾水处理效果越好。正交试验结果显示,以活性炭滤料、粒径为0.5~2 mm、滤料厚度为80 cm时,过滤装置对池塘圈养尾水具有最佳的综合处理效果,在该条件下对池塘圈养尾水的TSS、COD、NH_(4)^(+)-N去除率分别为83.86%、49.78%、29.89%。

危险货物道路运输个性化路径推荐方法

为加强危险货物道路运输风险源头管控,以危货运输车辆行驶轨迹数据为分析对象,研究安全、经济且符合企业自身偏好的道路运输路径优化选择问题,提出了基于偏好、上下文感知的危险货物道路运输个性化路径推荐方法。首先对危货运输车辆历史轨迹数据进行处理,通过提取路径安全和经济性特征学习危货运输企业的路径偏好,在此基础上,综合考虑偏好向量间的距离和方向相似性,提出了改进的K-means偏好聚类算法(improved K-means clustering algorithm based on distance and direction similarity measurement,DDM-K-means),获取了路径偏好类别;其次,依据运输任务执行的时间、天气、运距三方面信息,建立了路径上下文向量,并运用Rock聚类算法划分路径的上下文类别,与路径偏好类别共同构成路径信息;最终,基于神经协同过滤提出了危险货物道路运输路径选择优化算法(optimal route selection algorithm based on neural collaborative filtering,NCF-ORS),得到了危货运输企业对各路径类别的偏好排序,从而为企业推荐最优路径。与基线算法比较分析,结果表明危险货物道路运输个性化路径推荐方法<DDM-K-means,NCF-ORS>,平均绝对百分比误差最低。研究结果有助于挖掘车辆轨迹数据中更多的潜在信息,提升个性化路径推荐能力,可为危货运输企业的选线问题提供决策支持。

脱氮生物滤池在长三角地区城镇污水处理厂中的应用对比分析

选取长三角地区4座城镇污水处理厂中3种典型的脱氮生物滤池,从脱氮滤池设计参数、前后段工艺设计及实际运行情况进行了全面的对比分析。结果表明,滤料是影响滤池形式及运行成本的核心因素,也决定着上下游工艺的选择。在越来越严格排放标准的要求下,脱氮滤池的设计应在调查厂区现状和水质情况的基础上统筹考虑脱氮负荷的分配,保证各个水质指标的稳定达标。最后对实际应用中存在问题及对策进行了总结。

煤矿井下过滤站滤芯材料对比研究

系统分析了煤矿井下清水过滤站、回液过滤站和高压过滤站的污染物主要来源,并通过对煤矿井下常用的4种滤芯材料的性能对比分析,为过滤站与滤芯材料的合理匹配提出了解决方案,同时也为煤矿井下过滤站滤芯材料的选用提供了理论支撑。