A Novel Approach for Bolted T-Stub Connections

This paper reports an investigation into new connection types and their behaviors determined using full-scale experiments. T-shaped connections were created using the IPE standard profile. The aim of this study was to analyze the influence of T connections based on the IPE standard profile, height of beam to height of T-stub joint (H) of T-stub joints, and lengths (X) of T-stub joints on the behavior of steel connections, in order to provide the necessary data for improving Eurocode 3 and enable efficient use of residue IPE standard profiles and back to the consumption cycle. While the moment resistance values increased with an increase in H from H_min to H_max in model groups with X of 126 mm, and the energy dissipation increased with an increase in H from H_min to H_max and also with an increase in the lengths (X) of T-stub joints from 54 to 126 mm.     

多分量数据全波形反演在气藏检测中的关键问题——以苏里格气田为例

苏里格气田是中国典型的致密砂岩气藏，构造简单、平缓，横向非均质性强，有效储层与围岩声学特征差别小，地震响应不明显，常规地震监测方法预测难度大，但气田含气砂岩泊松比低，是地震气藏检测的有效参数。利用弹性全波形反演精度高和能处理复杂非均质介质的优势，反演地层拉梅常数、剪切模量和密度，并计算泊松比，从而进行气藏预测。重点阐述了苏里格气田多分量数据全波形反演初始模型建模、先验模型建模和地震数据预处理3个关键问题的处理方法。二维三分量数据反演和"甜点"预测结果表明：①对于具有强非均质性的苏里格气田，利用全波形反演获得精度较高的地层弹性参数能显著提高气藏预测的准确度；②苏里格地区构造简单、平缓，利用常规叠加速度并结合构造解释可以建立比较好的初始模型，从而有效地解决了周波跳跃和局部极小的难题；③先验知识的约束和地震数据的预处理是全波形反演成功应用于苏里格气田气藏检测的关键。     

Melt processing of ethylene–vinyl acetate/banana starch/Cloisite 20A organoclay nanocomposite films: structural,thermal and composting behavior

This work shows the preparation of ethylene vinyl acetate copolymer/banana starch/Cloisite 20A organoclay (EVA/starch/C20A) nanocomposites by melt processing. Wide angle X-ray diffraction (WAXD), field emission scanning electron microscopy (FE-SEM), differential scanning calorimetry and thermogravimetric analysis were used to characterize the obtained nanocomposites. Mechanical properties were also determined. In addition, the performance of the nanocomposite films under composting was preliminarily studied; it was conducted using the soil burial test method. Despite knowing that the starch is difficult to process by extrusion, nanocomposite films with high homogeneity were obtained. In this case, C20A organoclay acts as an effective surfactant to make the starch natural polymer compatible with the EVA synthetic polymer. The good compatibility between EVA, starch and C20A clay was also deduced by the formation of intercalated and intercalated-exfoliated structures determined by WAXD and FE-SEM. Physical evidence of the damage in EVA/starch/C20A nanocomposite films after the composting test was observed. It is worth noting that despite the absence of starch, the EVA/C20A nanocomposite film, used as a control, also showed surface damage. This behavior is related to the organic modifier linked to clay C20A, which contains molecules derived from fatty acids that can be used as a food source for microorganisms.

     

Toward a model of socializing project team members: An integrative approach

Project work is becoming more and more important in everyday business, as is staffing the right newcomers for the project. Recognizing that not all new project team workers possess equally important specific knowledge, skills and abilities for the success of projects, we draw on project management, human resource management, and organizational socialization literature to develop a framework on how new project team members might be socialized, depending on their strategic value for the project. We specifically draw on the socialization tactics literature and propose how four categories of new employees – Internal specialists, External specialists, External generalists and Internal generalists; based on two dimensions – work task complexity and employment mode, can be socialized more effectively. Implications for theory and practice are discussed as well.     

高分子絮凝剂处理高浓度化妆品原料生产废水研究

化妆品原料生产过程中产生的废水水质成分复杂、有机物含量高、难降解，利用混凝工艺处理该废水能够减缓生化处理单元的负担，提高污水处理效率。为揭示无机高分子混凝剂混凝过程中污染物的去除机制和污泥性质的变化，考察了不同的絮凝剂聚合氯化铝（PAC）、聚合硫酸铁（PFS）、聚合氯化铝铁（PAFC）和助凝剂聚丙烯酰胺（PAM）投加浓度对污染物去除率和污泥性质的影响。采用傅里叶变换红外光谱（FTIR）、X射线能谱（EDX）、扫描电镜（SEM）、热重分析仪（TGA）分析污泥絮体官能团、表面形貌、元素组成和热稳定性的变化，采用三维荧光光谱（3D-EEM）和超滤技术分析出水中有机物分子量的分布规律和有机物成分的变化，优化最佳混凝工艺运行条件。结果表明：进水中的天然有机物（NOM）荧光强度高，有机物分子量主要分布在>100×10³和<3×10³区间，其所占比例分别为22.89%和50.57%。当进水COD为6700~7500 mg/L时，在助凝剂PAM投加浓度为0.03 g/L，PAC、PFS和PAFC投加浓度分别为2.8 g/L、2.8 g/L和3.0 g/L的条件下，COD去除率分别为87.20%、79.89%和83.74%，出水浊度分别为2.54 NTU、9.3 NTU和5.51 NTU，NOM荧光强度大大减弱。其中，PAC+PAM对废水中有机物去除效果最好，出水有机物分子量主要分布在(10~30)×10³和<3×10³范围内，其所占比例分别为31.84%和25.92%，形成的混凝污泥具有较好的热稳定性，污泥表面蓬松,呈多孔网状结构。混凝工艺可吸附脂类大分子物质，提高了高浓度化妆品原料生产废水的可生化性。     

Influence of Ionic Liquid-Based Metal–Organic Hybrid on Thermal Degradation,Flame Retardancy,and Smoke Suppression Properties of Epoxy Resin Composites

A new multifunctional ionic liquid-based metal–organic hybrid (PMAIL) was synthesized by anion exchange between as-synthesized phosphonate-based ionic liquid and phosphomolybdic acid and applied to epoxy resin (EP) as an efficient flame retardant. As expected, with only 1 wt% addition of PMAIL, the char yield of EP-PMAIL1 composite at 700 °C was significantly improved by 108.3% from 12.0% for neat epoxy resin to 25.0%, demonstrating the outstanding catalytic charring effect of PMAIL. Meanwhile, EP-PMAIL6 composite (6 wt% addition) can reach V-0 rating in the UL-94 vertical burning tests easily, and its peak heat release rate and total smoke production of EP-PMAIL6 were dropped by 31.0 and 15.4%, respectively, compared with neat EP. Moreover, the results from cone calorimetry tests showed that the char yield of EP-PMAIL6 was enhanced by 162% from 9.5 to 24.9% compared with neat EP, resulting in a strong intumescent char layer structure with outstanding fire retardance and mechanical properties. The thermo-oxidative stable protective layer retarded the transfer of heat and flammable volatiles during combustion and protected the epoxy matrix from further degradation. In conclusion, our results might provide a new perspective for producing composites with excellent flame retardancy and smoke suppression properties using ionic liquid-based metal–organic hybrid.     

Catalytic pyrolysis and kinetic study of real-world waste plastics: multi-layered and mixed resin types of plastics

Clean Technologies and Environmental Policy - Multi-layered and mixed resin types of plastics are a great challenge for the waste recycling industry. The majority consist of two or more types of...     

南海钙质砂的动剪切模量与阻尼比试验研究

岩土体的动剪切模量和阻尼比是土工建筑物、近海场地动力稳定性分析中的主要动力学参数,为评价南海钙质砂的动力学特性,利用美国GCTS共振柱测试系统,对取自南海地区的钙质砂进行共振柱试验,研究固结压力、相对密实度对其动剪切模量和阻尼比的影响,并与石英砂进行对比分析。研究发现:相同的试验条件下,钙质砂的最大动剪切模量、阻尼比均大于石英砂;从总体而言,钙质砂的动剪切模量在剪应变小于0.1%时大于石英砂动剪切模量,在大于0.1%时两者趋于一致,其动剪切模量比G/Gmax随剪应变γ衰减的速度快于石英砂。根据试验结果建立钙质砂动剪切模量比G/Gmax、阻尼比D的数学模型,并结合现有的钙质砂动剪切模量比及阻尼比研究成果,给出钙质砂动剪切模量比和阻尼比的变化范围,为钙质砂场地工程建设中建筑物动力稳定性分析提供依据。