预应力预制叠合楼板耐火性能参数分析

在合理选择混凝土和预应力筋材料的热工参数、高温力学参数的基础上,采用有限元分析软件ABAQUS建立底面受火的预应力预制叠合楼板的高温热力学模型,计算结果得到已有试验结果的验证。对影响预应力预制叠合楼板高温力学性能的各参数进行有限元分析,结果表明:荷载水平和耐火保护层厚度对叠合楼板耐火性能的影响显著,混凝土强度、预应力筋截面配筋率等参数对叠合楼板的耐火性能影响较小,可以忽略不计;耐火保护层厚度一定时,叠合楼板的耐火极限随荷载水平的提高而降低;荷载水平一定时,叠合楼板的耐火极限随耐火保护层厚度的增加呈非线性提高。在ISO-834标准火灾作用下,叠合楼板跨中挠度变化率速率大于L2/(9000d)可作为其达到耐火极限的判别标准。选取荷载水平、混凝土保护层厚度两个重要影响参数进行分析,提出了叠合楼板的耐火极限取值建议,为预应力预制叠合楼板的抗火设计提供技术参考。     

太湖流域典型厂村融合区复合面源污染特征分析——以礼嘉镇、洛阳镇、雪堰镇为例

为把握厂村融合区工农业复合面源污染现状及特征,选取典型区域礼嘉、洛阳、雪堰3镇进行研究,结果表明,2017年3镇复合面源等标污染负荷总量为1. 85×10~9m~3/a,其中总氮(TN)等标负荷量最高,占总量的44. 73%,为优先控制因子; 57个行政村中,污染物负荷量及负荷强度均较高的行政村大多集中在洛阳镇和礼嘉镇,如圻庄村、天井村、毛家村、大路村等,为优先控制区域;各污染源中,农村生活污水和畜禽养殖贡献的等标污染负荷量最高,分别占总量的37. 88%和35.49%,其次是种植业和厂区面源,贡献率分别为13. 17%和12. 77%,水产养殖贡献率最低;通过聚类分析将厂村融合区复合面源污染类型分为6类。     

In situ synthesis of potassium tungstophosphate supported on BEA zeolite and perspective application for pesticide removal

Potassium tungstophosphate is supported on BEA zeolite by in situ synthesis for glyphosate removal. Spectroscopic measurements identified hydrogen bonding as a primal interaction of potassium salt and BEA zeolite. Composites are evaluated for glyphosate herbicide removal and adsorption process is analyzed using two isotherm models. Obtained adsorption capacities for all prepared composites lay between 45.2 and 92.2?mg of glyphosate per gram of investigated composite. Suspension acidity revealed that glyphosate is adsorbed mainly in the zwitter-ion form at the composite surface while the amount of potassium salt in the composites is crucial for the adsorption application. Exceptional adsorption behavior is postulated to come from a high degree of homogeneity among surface active sites which is confirmed by different experimental methods. Temperature programmed desorption of glyphosate coupled with mass spectrometer detected one broad, high-temperature peak which represents overlapped desorption processes from active sights of similar strength. Introduction of potassium tungstophosphate affects active sites present in BEA zeolite for glyphosate desorption and significantly increases the amount of adsorbed pesticide in comparison to BEA zeolite. Supporting of potassium tungstophosphate on BEA zeolite via in situ synthesis procedure enables the formation of highly efficient adsorbents and revealed their perspective environmental application.     

东荣三矿粉煤灰复合胶体防灭火技术应用与实践

双鸭山东荣三矿2 0 0 3年发生火灾,开始应用注水、注惰、注灭火剂等方法,均未控制住火势。后来,通过该矿现有的灌浆系统,形成复合胶体管网式防灭火系统,利用该系统向火区周围密闭墙内大量压注粉煤灰复合胶体,堵塞了向火区漏风的通道,扑灭了大范围火源。接着启开火区下部的运输上山,从运输上山向火区打钻,由钻孔直接向火区注复合胶体,彻底扑灭了火灾,保障了矿井安全生产。实践表明,复合胶体管网式防灭火技术是一种快速高效的防灭火技术,适应大面积煤层火灾的防治要求。     

Simple fabrication of carboxymethyl cellulose and κ-carrageenan composite aerogel with efficient performance in removal of fluoroquinolone antibiotics from water

● A composite aerogel was simply obtained to remove various fluoroquinolones (FQs). ● The structural and textural properties of this composite aerogel are improved. ● Its adsorption capacity was improved at a low content of coexisting Cu²⁺ or Fe³⁺ ion. ● Two substructural analogs of FQs are compared to explore the adsorption mechanisms. ● This aerogel after saturated adsorption can be reused directly for Cu²⁺ adsorption. 3D composite aerogels (CMC-CG) composed of carboxymethyl cellulose and κ-carrageenan were designed and fabricated using the one-pot synthesis technique. The optimized CMC-CG showed a good mechanical property and a high swelling ratio due to its superior textural properties with a proper chemically cross-linked interpenetrating network structure. CMC-CG was utilized for the removal of various fluoroquinolones (FQs) from water and exhibited high adsorption performance because of effective electrostatic attraction and hydrogen bonding interactions. Ciprofloxacin (CIP), a popular FQ, was used as the representative. The optimized CMC-CG had a theoretically maximal CIP uptake of approximately 1.271 mmol/g at the pH of 5.0. The adsorption capacity of CMC-CG was improved in the presence of some cations, Cu²⁺ and Fe³⁺ ions, at a low concentration through the bridging effect but was reduced at a high concentration. The investigation of adsorption mechanisms, based on the adsorption kinetics, isotherms and thermodynamic study, Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy analyses before and after adsorption, and changes in the adsorption performance of CMC-CG toward two molecular probes, further indicated that electrostatic attraction was the dominant interaction rather than hydrogen bonding in this adsorption. CMC-CG after saturated adsorption of CIP could be easily regenerated using a dilute NaCl aqueous solution and reused efficiently. Moreover, the disused aerogel could still be reused as a new adsorbent for effective adsorption of Cu²⁺ ion. Overall, this study suggested the promising applications of this composite aerogel as an eco-friendly, cost-effective, and recyclable adsorbent for the efficient removal of FQs from water.     

污染程度的模糊综合评判

污染程度的确定受多种污染因素的影响和制约,本文运用模糊数学理论与方法分析了各种污染影响因素的模糊性和随机性,通过主观和客观评价,模糊变换而得出了污染程度的综合评判模式,为企业生产的环境管理和决策提供了科学依据。     

A Synthetic Filter Material Containing Nutrients for Biofilter

In this study, a synthetic filter material with nutrients (PVA/peat/KNO₃ composite bead) was developed for biofilteration. The optimal preparing condition was each of the peat and PVA aqueous solutions mixed with 6.4 g KNO_3, and the minimum nitrogen content in the boric and phosphate aqueous solutions was 3.94 and 1.52 g-N/l, respectively. The equilibrium amount of inorganic nitrogen extracted by leaching from the prepared composite bead was between 7.95 and 8.21 mg N/g dry solid. The path of inorganic nitrogen extracted by leaching was the inorganic nitrogen dispersed in the peat phase firstly diffused into the outer PVA phase and then it diffused out of the bead surface for the A-type bead; and that was the inorganic nitrogen dispersed in both the peat and PVA phases simultaneously diffuses into the outer PVA phase and out of the bead surface, respectively, for the H-type bead. The microbial growth rate k _g of the H-type composite bead was higher than that of the A-type composite bead about 1.09–1.58 times, and the maximum value of k _g was at the H-type composite bead immersed in 0.384 M KNO₃ aqueous solution. The percentage of removed VOCs retained at more than 98% during the biofilter operating 230 days as the composite bead immersed in KNO₃ aqueous solution before packing. This composite bead bed was without the further addition of nutrients during the operating period.     

Characterization of Biodegradable Composite Films Prepared from Blends of Poly(Vinyl Alcohol), Cornstarch,and Lignocellulosic Fiber

Several composite blends of poly(vinyl alcohol) (PVA) and lignocellulosic fibers were prepared and characterized. Cohesive and flexible cast films were obtained by blending lignocellulosic fibers derived from orange waste and PVA with or without cornstarch. Films were evaluated for their thermal stability, water permeability and biodegradation properties. Thermogravimetric analysis (TGA) indicated the suitability of formulations for melt processing, and for application as mulch films in fields at much higher temperatures. Composite films were permeable to water, but at the same time able to maintain consistency and composition upon drying. Chemical crosslinking of starch, fiber and PVA, all hydroxyl functionalized polymers, by hexamethoxymethylmelamine (HMMM) improved water resistance in films. Films generally biodegraded within 30 days in soil, achieving between 50–80% mineralization. Both starch and lignocellulosic fiber degraded much more rapidly than PVA. Interestingly, addition of fiber to formulations enhanced the PVA degradation.     

强震前后短期内的异常天气及灾害叠加

列叙了部分强震前后短期的异常气象情况，探讨了其与强震间的机理，并结合１９７６年松潘７．２有地震波及汉中地区引起的破坏，讨论了异常天气带来的灾害叠加问题，对编制防震减灾规划和地震短临前兆探索，无疑是有益的。     

水泥土深层搅拌桩在某工程中的设计与应用

结合实际工程介绍了水泥土深层搅拌桩在复杂软弱场地中的设计及应用。