Ultrasound‐activated Knoevenagel condensation of malononitrile with carbonylic compounds catalysed by alkaline‐doped saponites

α,β‐Unsaturated nitriles have been synthesized by Knoevenagel condensation of a carbonylic compound with malononitrile, assisted by sonochemical irradiation. Two alkaline‐promoted clays (Li⁺‐ and Cs⁺‐exchanged saponites) have been employed as catalysts. The influence of the carbonylic compound (benzaldehyde or cyclohexanone) and the use of a solvent on the catalytic activity have been studied. Remarkable increase in the conversion values has been found when the reaction is activated by ultrasound, as compared with the thermal activation. In this green, solvent‐free procedure, α,β‐unsaturated nitriles have been produced in very high yields (97%) when the Cs⁺‐saponite is used as catalyst. Copyright © 2004 Society of Chemical Industry     

Nutrient removal performance of an anaerobic–anoxic–aerobic process as a function of influent C/P ratio

The laboratory scale anaerobic–anoxic–aerobic (A²O) process fed with synthetic brewage wastewater was designed to investigate the effects of changing feed C/P ratio on the performance of biological nutrient removal (BNR) processes. In the experiment, the influent chemical oxygen demand (COD) concentration was kept at approximately 300 mg L^?1 while the total phosphorus concentration was varied to obtain the desired C/P ratio. Results showed that when the C/P ratio was lower than 32, phosphorus removal efficiency increased as C/P ratio increased linearly, while when the C/P ratio was higher than 32, the P removal efficiency was maintained at 90–98%, and effluent P concentration was lower than 0.5 mg L^?1. However, regardless of the C/P ratio, excellent COD removal (90% or higher) and good total nitrogen removal (75–84%) were maintained throughout the experiments. It was also found that very good linear correlation was obtained between COD uptake per unit P released in the anaerobic zone and C/P ratio. In addition, the P content in the wasted activated sludge increased with the decrease in the C/P ratio. Based on the results, it was recommended that the wastewater C/P ratio and its effects be incorporated into BNR design and operational procedures, appropriate C/P ratios were used to achieve the effluent treatment goals. Copyright © 2005 Society of Chemical Industry     

Analysis of supersaturation and nucleation in a moving solution droplet with flowing supercritical carbon dioxide

A supercritical antisolvent (SAS) process is employed for production of solid nanoparticles from atomized droplets of dilute solution in a flowing supercritical carbon dioxide (SC CO₂) stream by attaining extremely high, very rapid, and uniform supersaturation. This is facilitated by a two‐way mass transfer of CO₂ and solvent, to and from the droplet respectively, rendering rapid reduction in equilibrium solubility of the solid solute in the ternary solution. The present work analyses the degree of supersaturation and nucleation kinetics in a single droplet of cholesterol solution in acetone during its flight in a flowing SC CO₂ stream. Both temperature and composition are assumed to be uniform within the droplet, and their variations with time are calculated by balancing the heat and mass transfer fluxes to and from the droplet. The equilibrium solubility of cholesterol with CO₂ dissolution has been predicted as being directly proportional to the Partial Molar Volume Fraction (PMVF) of acetone in the binary (CO₂–acetone) system. The degree of supersaturation has been simulated up to the time required to attain almost zero cholesterol solubility in the droplet for evaluating the rate of nucleation and the size of the stable critical nuclei formed. The effects of process parameters have been analysed in the pressure range of 7.1–35.0 MPa, temperature range of 313–333 K, SC CO₂ flow rate of 0.1136–1.136 mol s^?1, the ratio of the volumetric flow rates of CO₂‐to‐solution in the range of 100–1000, and the initial mole fraction of cholesterol in acetone solution in the range of 0.0025–0.010. The results confirm an extremely high and rapid increase in degree of supersaturation, very high nucleation rates and stable critical nucleus diameter of the order of a nanometre. Copyright © 2005 Society of Chemical Industry     

二价金属离子对UASB颗粒污泥的影响

分析了Mg^2 、Ca^2 、Fe^2 等二价金属离子对UASB反应器中厌氧颗粒污泥的影响。     

中频反应溅射SiO2膜与直流溅射ITO膜的在线联镀

多数ITO透明导电玻璃生产线在实现SiO2膜与ITO膜在线联镀时，应用SiO2靶射频溅射沉积SiO2膜工艺和ITO靶直流溅射沉积ITO膜工艺，如果SiO2膜应用硅靶反应磁控溅射工艺，存在这种工艺是否可以与ITO靶直流溅射沉积ITO膜工艺在线联用以及如何实现联用的问题。作者对现有的生产线进行了改造设计、加工，做了大量实验、质谱分析和多项测试研究，成功地实现反应溅射SiO2膜与ITO膜在线联镀，做到SiO2镀膜室的工作状态的变化基本上不影响ITO镀膜室的工艺条件。     

溶胶-凝胶法制备疏水型SiO-2气凝胶

以正硅酸乙酯 (TEOS)为硅源 ,用三甲基氯硅烷 (TMCS)为疏水试剂 ,通过溶胶 凝胶法在室温下制备出疏水型SiO2 气凝胶。用傅立叶变温红外 (FT IR)、扫描电镜 (SEM)、透射电镜 (TEM)和吸水性能对疏水型SiO2气凝胶的结构和性能进行了研究     

Inhibitory activity of ginger rhizome on airway and uterine smooth muscle preparations

In this study, we describe the tracheal-relaxant and tocolytic activities of the methanol (ME) and aqueous (AQ) crude extracts of ginger (rhizome of Zingiber officinale) in an attempt to rationalize its traditional use in disorders of airways and uterine hyperactivity. Both of the ginger extracts dose-dependently relaxed K⁺ (80 mM) and carbachol (CCh, 1 μM)-induced contractions with more potency against K⁺, similar to that elicited by verapamil, a Ca²⁺ channel blocker. In isolated uterine preparations, the extracts suppressed the K⁺-induced contractions with respective EC₅₀ values of 0.03 mg/ml (0.02–0.05, 95% CI) and 0.05 mg/ml (0.04–0.06). Activity-directed fractionation of AQ yielded an organic and an aqueous fraction with the activities concentrated in the former. Both the crude extracts were found safe in mice up to the oral dose of 5 g/kg when tested for acute toxicity for 24 h. The study shows that ginger possesses tracheal and uterine smooth muscle relaxant activity, possibility mediated via Ca²⁺ channel blockade, justifying its use in disorders such as asthma, cough as well as in dysmenorrhoea and uterine and menstrual spasms and congestion.     

乙炔在磁稳定床中的选择性加氢研究

 制备了一种磁性Pd/Al₂O₃催化剂，采用磁稳定床考察了活性组分负载量、反应条件及CO浓度对乙炔加氢反应性能的影响。结果表明，当反应温度80℃、反应压力1.5MPa、空速9000h－1、磁场强度（H）25kA/m时，乙炔转化率为100％，乙烯选择性可达81％，具有优良的乙炔加氢活性和乙烯选择性，优于相同反应条件下的进口催化剂；250h稳定性实验结果表明，磁性Pd/Al2O3催化剂具有良好的初活性和乙烯选择性，催化剂性能稳定。     

Supercritical gases pasteurization of apple juice

Supercritical CO₂ and N₂O pasteurization of apple juice, inoculated with Saccharomyces cerevisiae as test microorganism, was performed at 36 °C on a laboratory multi-batch apparatus of a total volume of 150 ml. The pressure values ranged from 100 to 200 bar. Experimental results indicate the effectiveness of the method proposed. A stochastic model of the process was developed on the basis of the experimental evidence: high-pressure inactivation curves were analysed using a stochastic model based on multi-hit model. Furthermore, the samples of the cells subjected to high-pressure treatments were examined by environmental scanning electron microscopy (ESEM) to determine the effect of the process on the cell wall.     

Satellite SAR Remote Sensing of Great Lakes Ice Cover,Part 2. Ice Classification and Mapping

During the 1997 winter season, shipborne polarimetric backscatter measurements of Great Lakes (freshwater) ice types using the Jet Propulsion Laboratory C-band scatterometer, together with surface-based ice physical characterization measurements and environmental parameters, were acquired concurrently with Earth Resource Satellite 2 (ERS-2) and RADARSAT Synthetic Aperture Radar (SAR) data. This polarimetric data set, composed of over 20 variations of different ice types measured at incident angles from 0° to 60° for all polarizations, was processed to radar cross-section to establish a library of signatures (look-up table) for different ice types. The library is used in the computer classification of calibrated satellite SAR data. Computer analysis of ERS-2 and RADARSAT ScanSAR images of Great Lakes ice cover using a supervised classification technique indicates that different ice types in the ice cover can be identified and mapped, and that wind speed and direction can have an influence on the classification of water as ice based on single frequency, single polarization data. Once satellite SAR data are classified into ice types, the ice map provides important and necessary input for environmental protection and management, ice control and ice breaking operations, and ice forecasting and modeling efforts.