生物除臭技术介绍及在石化废水上的工程应用

采用以炭质生物媒为填料的生物除臭工艺为主的除臭技术,对宁波某石油化工废水处理过程中产生的臭气进行净化。结果表明,水洗+生物除臭系统在臭气与填料的接触时间大于12 s,进水pH控制在7左右,出水pH控制在2左右,当进口臭气中H2S浓度变化范围为24.5~122.5 mg/m3时,H2S的去除率大于95.3%。当进口臭气中NH3浓度的变化范围为0.2~2.0 mg/m3时,NH3的去除率大于50%,均可达到排放标准的要求,且水洗+生物除臭系统具有较强的耐高浓度污染物负荷的冲击能力。     

Stable Organic Titanium Catalysts and Reactive Distillation Used for the Transesterification of Dimethyl Carbonate with Phenol

The transesterification of dimethyl carbonate with phenol to methyl phenyl carbonate (MPC) was investigated on novel catalysts such as titanium diisopropoxide bis(ethyl acetoacetate) and titanium dibutoxide bis(ethyl acetoacetate) in a closed batch reactor at 185–206 °C under high pressure. The produced methanol could be removed efficiently by reactive distillation in order to overcome the equilibrium. The prepared catalysts have higher resistance to water than titanium alkoxides. Phenol conversion as high as 86.4 % with an MPC selectivity of 99.4 % was achieved under optimal reaction conditions within 9 h. Most of the catalytic activity was retained after repeated use for ten times.     

盐渍土环境输电线路基础钢筋阻锈技术对比试验研究

针对盐渍土环境下钢筋混凝土阻锈材料,通过对比试验系统分析了无机亚硝酸盐和有机氨基醇两类阻锈剂材料对混凝土抗压强度、模拟液和砂浆中钢筋锈蚀电化学行为的影响,结果表明:相比于无机阻锈剂,有机阻锈剂不仅在模拟液中有效抑制钢筋腐蚀,在干湿交变、高氯盐环境中发生破损时,对钢筋的保护作用更优。     

非饱水冻融作用下的古砖动弹性模量

弹性模量是反映材料刚度的重要指标。自然界中雨淋和冻融导致古建筑砌体砖处于非饱水冻融状态。通过大气环境实验舱对古砖进行非饱水冻融作用下的饱和系数、饱水度、动弹性模量、相对动弹性模量等技术参数实验,分析了非饱水冻融作用下古砖弹性模量变化规律。实验结果表明,饱水度大于等于60%时,非饱水冻融导致古砖试件动弹性模量和相对动弹性模量数值均出现明显下降趋势;饱水度小于60%时,非饱水冻融对动弹性模量和相对动弹性模量数值影响较小。非饱水冻融作用下,古砖的初始抵抗风化能力大小是影响动弹性模量和相对动弹性模量数值的重要因素。同时,对非饱水冻融作用下反映古砖抵抗冻融损伤能力的极限饱水程度等关键参数进行了讨论。     

Cryogenic performance of single polymer polypropylene composites

The main objective of the experimental study detailed in this paper is to investigate the performance of fully recyclable, lightweight, low-cost, thermoplastic Polypropylene (PP) composite tapes at low temperatures. Coupons made of [±45] and [0/90] laminates are subjected to tensile and 3-point bending tests at room temperature as well as at −196 °C. In addition to that, cryogenic low velocity impact tests at 268 J and 777 J impact energies are performed on tubular structures. The results are indicating that the laminates made of PP tapes have sufficient ductility for cryogenic applications. Low velocity impact tests showed that the viscoelastic behavior of the material is preserved, even at such low temperatures and more than 72% of impact energy is absorbed by the material.     

Evaluation of clear-sky conditions in high altitude sites

The correct assessment of cloud conditions in any site is important for determining the characteristics of solar resource availability. The criterion proposed by Iqbal has been widely used for this purpose, through the classification of the daily clearness index K_t. However, evidence was found to suggest that this criterion may not be applicable to data measured in high altitude sites, because partially cloudy days are incorrectly classified as clear-sky days. This paper analyzes the cloudiness state of the sky by observing the values of the clearness index K_t and the clear-sky index K_c. These indices were obtained from reliable global solar irradiance data measured over a year in three places of Argentina located at different altitudes (25, 1200 and 3700 m.a.s.l). ESRA and ARG-P models were used to estimate daily clear-sky global solar irradiation values H_c. They also reveal that the most probable value of K_c which corresponds to an actual clear-sky day of a particular location and time depends on the model used to estimate the clear-sky global solar radiation values. Thus, it was confirmed that, unlike the index K_c, the Iqbal's criterion does not correctly classify the cloud cover status from data measured in high altitude sites (>1000 m.a.s.l.).     

Effect of exopolysaccharides from lactic acid bacteria on the texture and microstructure of buffalo yoghurt

To examine the effect of exopolysaccharides (EPS) on the microstructure and textural and rheological properties of yoghurt, purified EPS were added to buffalo milk to make yoghurts. The results showed that the viscosity, water-holding capacity, hardness, and microstructure of yoghurt were distinctly affected by the level of addition of EPS. With the increasing amount of supplemented EPS, the viscosity of buffalo yoghurt showed a downward trend with the increasing shear velocity, and an increasing degree of recovery of viscosity with the decrease in shear velocity, indicating that the steric barrier formed between the EPS and protein enhanced the viscoelastic properties. The microstructure showed more dense interspaced voids with EPS addition.     

Corrosion protection performance of microsilica added concretes in NaCl and seawater environments

In a hardened concrete structure, diffusion of oxygen, carbon dioxide, aggressive ions and moisture from the concrete/environment to the concrete/rebar interfaces takes place through the pores. This results in the failure of the passivation provided by the alkalinity of the cement to the rebars. Microsilica is a mineral that improves the corrosion protection and strength of concrete by reducing the permeability of the concrete and forming more calcium silicate hydrate (CSH) which provides strength and durability to concrete. In order to study the corrosion protection behavior of microsilica in ordinary Portland cement (OPC) and sulfate resistant cement (SRC), carbon steel reinforced concrete specimens of above cements containing 10% each of densified (DMS) and undensified (UDMS) microsilica were exposed to 5% NaCl solution and seawater. Corrosion of rebars was monitored using open circuit potential (OCP) measurements. Diffusion of ions into the concrete was studied by salt ingress, salt fog and rapid chloride permeability tests. It has been noted that densified microsilica provides better corrosion protection to the rebars than the undensified one. In addition to this its protective effect with SRC is much more than with OPC. An attempt has been made to explain the mechanism of corrosion protection behavior of microsilica added concrete immersed in seawater and NaCl solution.     

古代砖砌体风化性能分析及风化程度评定

自然界中气温、降水的长期作用导致古代砖砌体风化,风化损伤材料和砌体力学性能。实验采用大气环境实验舱实现自然风化作用人工模拟,根据不同饱水度和冻融次数,实验舱设定了7种非饱水冻融工况,对7种工况影响下的砖、灰浆、砌体抗压、砌体抗剪试件试件强度变化规律进行实验分析。实验表明,饱水度是反映材料冻融性能的重要指标;不同饱水度下的冻融试件强度呈现先升后降的趋势;试件在饱水度为53%的冻融作用下,砌体构件具有最佳抗力;提出古代砖砌体构件风化程度评定标准。实验对古砖砌体结构保护工作具有指导和应用价值,定期评定古塔砌体风化程度,时刻掌握古塔构件结构安全性能的变化规律,科学保护古塔。