钢管表面高压水除鳞效果分析与对策

介绍了钢管表面高压水除鳞系统的工作原理;分析了影响钢管表面高压水除鳞效果的设备问题;探讨了钢管表面生红锈的化学机理。通过改进高压单向截止阀设计和曲轴进油口的密封形式,并通过实验对比选择小直径喷嘴解决了钢管表面生红锈的问题,并在保证钢管表面不生红锈的同时取得了良好的除鳞效果。     

Simultaneous determination of melamine and cyanuric acid in dairy products by mixed-mode solid phase extraction and GC–MS

This report described a method for simultaneous determination of cyanuric acid (CYA) and melamine (MEL) in dairy products. The samples were extracted by a mixture of acetonitrile/water and cleaned by graphite carbon/strong cation exchange (CARB/SCX) mixed-mode solid phase extraction column. The CYA and MEL were derivatized with bis(trimethylsily1)trifluoroacetamide (BSTFA) containing 1% Trimethylchlorosilane (TMCS), and quantified with the internal standards of ¹⁵N₃-cyanuric acid and ¹³C₃-melamine by GC–MS. The results indicated that CARB/SCX mixed solid phase extraction column could be used for sample pretreatment. The fortification recoveries were 80.8–101.5%, and the relative standard deviations (RSDs) were 3.6–7.9%. The detection limits of CYA and MEL were 0.025 mg kg⁻¹ and 0.01 mg kg⁻¹ respectively.     

Novel approach to correlate degree of surface deterioration to coating impedance for laboratory test panels coated with two types of primers

Abstract

Relationships between deteriorated coating surface conditions of laboratory test panels determined by image processing software and coating impedance data collected with electrochemical impedance spectroscopy (EIS) were investigated. A unique relationship was found between the log?|Z|_0·1 values of experimental EIS data and the corresponding deteriorated area ratios determined by the image processing method. A well defined one to one relationship was also found between log?|Z|_0·1 values and log?(R_po) values extracted through EIS data fitting analysis. This study demonstrates that estimation of log?(R_po) at a certain deterioration stage is feasible via field image processing alone without running in situ EIS measurements and going through time consuming EIS fitting analysis. A field coating maintenance program established by this methodology can be an effective tool for bridge maintenance engineers who need to make timely decisions on coating repair/rehabilitation work based on the quantitative ‘visual’ image scan results and ‘invisible’ coating pore resistance.     

Studies on the interactions between bovine β-lactoglobulin and chitosan at the solid-liquid interface

Chitosan ultrathin films have been formed on polycrystalline Au substrates using the LbL technique with the purpose of studying its interaction with bovine β-lactoglobulin (β-LG) at the solid-liquid interface. The immobilization of chitosan was followed by Quartz Crystal Microbalance with energy dissipation (QCM-D), Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). The behavior of the chitosan films in the presence of β-LG solutions with different bulk concentrations ([β-LG]), ionic strength (I), and pH has been investigated using the same techniques plus Atomic Force Microscopy (AFM). The results showed that for pHs lower than protein's pI, weak intermolecular forces (H bonding, Van der Waals, hydrophobic, etc.) are established between β-LG and chitosan (especially close to the pI) leading to low coverage nonspecific adsorption. On the contrary when pH > pI, strong ionic bonding through attractive electrostatic interactions lead to high coverage adsorbed phases composed of large β-LG aggregates. The adsorption process was shown to consist of a relatively fast step (in which these interactions are predominant) which is followed, once the β-LG monolayer is exceeded, by the slow formation of thicker and increasingly viscoelastic films through β-LG self-aggregation. QCM-D and AFM experiments unveiled the role of [β-LG] and I on the formation of these aggregates. The adsorption isotherm built from impedance data in the medium-low [β-LG] range (0.001-0.3 mg mL⁻¹), showed good fitting to the Langmuir model confirming that the formation of one β-LG monolayer is achieved in this concentration range.     

Pretreatment of Steel Racetracks by Using Sand-Blasting Technique with a Special Emphasis on Si3N4 Powder–Part Two

Fatigue testing of the Si₃N₄ sand-blasted 52100 steel race is continued by using a clean lubricant and powder-contaminated lubricant samples, as well as an initial “run-in” segment to precondition the sand-blasted racetracks. It was found that the potential of sand-blasted steel race is best realized in “hybrid” bearings where the adverse impact of lubricant borne solid particulates can be wholly avoided under our current test condition. By and large, prolonged fatigue life of the Si₃N₄ sand-blasted racetrack has been observed due to the formation of Si₃N₄ surface layer and when used in a solid-contaminated lubricant environment.     

Prediction of Layer‐Inversion Behavior of Down‐Flow Binary Solid‐Liquid Fluidized Beds

The layer‐inversion behavior of down‐flow binary solid‐liquid fluidized beds is predicted using the property‐averaging approach. The binary pair in this case consists of a larger solid species which is also heavier than its smaller counterpart, while both are lighter than the fluidizing medium. The model is based on using the generalized Richardson‐Zaki correlation for evaluation of the bed void fraction wherein mean values of particle properties are used. However, unlike the maximum bulk density condition for the conventional up‐flow binary solid fluidized bed, the model is based on a minimum bulk density condition for occurrence of layer inversion. This is due to the fact that the volume contraction phenomenon associated with the mixing of unequal solid species leads to a decrease in bulk density of the bed. Model predictions are also compared using the limited data available in the literature. Predictions are consistent with the observed mixing behavior.     

Pretreatment of Steel Racetracks by Using a Sand-Blasting Technique with a Special Emphasis on Si3N4 Powder—Part Three

Additional rolling fatigue experiments as well as pure sliding, bending, and scratching tests of the Si₃ N ₄ sand-blasted steel surface have been carried out. Acquired results reconfirm the extraordinary tenacity of the self-attaching Si₃ N ₄ surface layer in terms of both anti-fatigue and antiwear characteristics, especially in the “hybrid” ball bearing. It appears that this Si₃ N ₄ sand layer can be identified as a complex, self-organizing, and adaptive system.     

The PhytO3 Tech Crop Protection Technology – Trial Results in a 2,700 ha (6,500 acre) Soy Farm in Brazil

Extended field trial testing of the PhytO3 technology (applying sequentially and rapidly electrolyzed water, ozone in water, and UV-C radiation to control insects and replace chemical sprays) was conducted in Brazil on growing soy bean crops during December 2006 to March 2007. Despite the very poor growing conditions because of excessive rainfalls, the test crops all reached harvest and provided significant economic benefits to the farmer. Details of the testing program are described. In addition to eliminating the need for pesticides and insecticides, crops treated by the PhytO3 technology qualify as organic-grown crops, and therefore command about double prices on world markets.     

Efficient routing for IP subnet VLAN over Ethernet

Existing IP routing algorithms have been developed mainly for non‐VLAN networks. For these routing algorithms to work, an end station must be attached to its associated network. The introduction of VLAN has, however, allowed the physical location of the end station to be changed from time to time. Therefore, some extra mechanism is required to support routing in VLAN environment. Existing approaches have some drawbacks in terms of inefficiency in traffic forwarding and switch software complexity. In this paper, a simple and efficient method for routing over IP subnet VLAN in Ethernet is proposed. This method has been implemented in hardware and found to work correctly. Various measurements and analyses have been performed to verify the efficiency of this protocol. Copyright © 2002 John Wiley & Sons, Ltd.