Fluorometric analysis of inertinite

In coal petrology, fluorescence microscopy has mainly been used in the study of liptinite (exinite) macerals. Recently, its scope of application has been widened to investigate vitrinite. This paper describes the conditions under which inertinite can also be studied by fluorometry. The method makes use of relatively long-wave excitation. Although the strongest signals are received through a green exciter filter at 546 nm, blue light excitation (450–490 nm) is preferred because the fluorescence spectrum is broader, the microscopic image more polychromatic and maceral identification is easier compared with longer-wave excitation. Inertinite macerals are divided into fluorescent and non-fluorescent constituents on the basis of both visual distinction and relative intensity determinations at 650 nm measuring wavelength. It appears that fluorescent inertinite corresponds closely to reactive fractions determined by previous coking experiments.     

Catalytic denitrification: direct and indirect removal of nitrates from potable water

A nitrate removal process that drastically reduces salt consumption and waste discharge has been developed on a bench scale. Nitrate is removed by chloride ion exchange, and the strong-base anion resin is completely regenerated at mild reaction conditions (i.e., ambient temperature, atmospheric pressure) in a closed circuit containing a single-flow fixed-bed reactor packed with a Pd–Cu/γ-Al₂O₃ catalyst. The combined treatment system avoids direct contact between the denitrification reactor and the water to be treated, and minimizes operational problems associated with each separate technique. No dissolution of Pd and Cu metallic-phases was observed at the given operating conditions.     

Cure monitoring of photosensitive resins by photo-dynamic mechanical analysis

A new technique, photo-dynamic mechanical analysis, was developed to monitor the cure of photosensitive resins. In this technique, the resin is dispensed on a low modulus substrate and the force needed to maintain a prescribed elongation on the sample is measured while the sample is exposed to an ultraviolet source. The force increases with the extent of cure and reaches a plateau when the resin is fully cured. Photo-dynamic mechanical analysis was found to be a rapid, continuous, and reliable technique to monitor the extent of cure of photopolymerizable resins. A finite element analysis was developed to calculate the resin modulus from the experimental force data. Thus, it was possible to monitor the resin modulus from the liquid state to the solid state.     

The use of thermal analysis in assessing the effect of temperature on a cement paste

Upon heating, the cement paste undergoes a continuous sequence of more or less irreversible decomposition reactions. This paper reports studies on a cement paste fired to various temperature regimes up to 800 °C in steps of 100 °C for a constant period of 24 h. This work has been carried out using thermal analysis technique to study the effect of temperature in the mineralogical composition of cement hydration products. The thermal decomposition of the cement paste is analysed with the thermogravimetric analysis (TGA) and the derivative thermogravimetric analysis (DTG) curves. Such techniques can be used to determine fire conditions and the consequent deterioration expected in the cement paste. Therefore, the aim of this work is to have a better knowledge of the reactions that take place in a cement paste during a fire and thus to be able to determine the temperature history of concrete after a fire exposure. The results show that even if the dehydroxylation reaction is reversible, the portlandite formed during the cooling has an onset temperature of decomposition lower than the original portlandite and can thus be considered as a tracer for determining the temperature history of concrete after a fire exposure.     

Particle size analysis of plasticized PVC dispersion resins using the photometric centrifugal sedimentation method

There are many known methods for determining the particle size distribution of PVC dispersion resins. Most of these methods require that the resin be in an aqueous medium. PVC dispersion resins are used primarily in a plasticizer medium. The shearing action that takes place when the resin is mixed in plasticizer and the subsequent solvating action of the plasticizer affect the particle size distribution of the dispersion resin. It is advantageous to be able to determine the particle size distribution of the plasticized resin since it can affect various properties such as rheology, gloss and foam quality. It is the purpose of this paper to show that a fast zonal sedimentation technique can be used to analyze the less than 20 μ particle size fraction of a dispersion resin after it has been mixed in a plasticizer system. This can be accomplished in less than 90 minutes. This technique can be used to relate particular dispersion resin properties to the particle size distribution of the resin. The method can also be used as a quality control test.     

注气锅炉含盐废水的分析及回用技术研究

油田注汽锅炉的离子交换树脂系统在再生过程中要排放大量含盐废水，这部分废水中含有大量氯离子和硬度离子，外排后会对耕地造成不良影响。本研究以重复利用这部分含盐废水为目标，对离子交换树脂再生过程中的各阶段含盐废水进行现场取样，并对水样进行水质分析，在此基础上进行了废水回用工艺研究，设计方案不仅可以重复利用废水中的氯化钠，而且可将含盐废水转化为清水回用，从而节约大量清水和氯化钠，为油田带来良好的经济效益和社会效益。     

Fraktionierung und Charakterisierung von ungehärteten Epoxidharzen aus Bisphenol A und Epichlorhydrin

Gel permeation chromatography and thin layer chromatography have been used respectively to separate and characterize the first seven members of an epoxy resin polymer homologous series on a preparative and analytical scale. The epoxy resin was formed by the reaction between Bisphenol-A and epichlorhydrin. NMR was used to identify the oligomers. The relationship between extinction coefficient and degree of polymerisation was also determined.     

Numerical simulation of double-bag progressive compression method of resin delivery in liquid composite moulding

ABSTRACT

An improved technique of resin delivery, called double-bag progressive compression method (DBPCM), has been developed to manufacture composite parts associated with the vacuum infusion (VI) process. During resin infusion, both bags are pulled upward by the vacuum and the flow resistance offered by the preform is reduced. After the completion of resin infusion, the vacuum on the segmented bags are progressively released to atmospheric pressure allowing the inflated bags to squeeze the surplus resin from the saturated preform. During progressive compression, the dry preform is kept loose and resin easily flows into the preform interstices. Heated air can be utilised at the appropriate compression segment. After the entire preform is wetted, the post-filling stage is carried out to obtain a uniform thickness of the component. This paper describes the numerical results of DBPCM complete filling process in finite difference analysis. The typical VI process is also modelled for comparison purpose.     

基于熵权灰关联度分析法的煤样识别研究

针对常用煤炭识别方法样本数据要求高、人为因素影响大、识别准确性差等问题,提出一种基于信息熵的灰色关联度分析方法。通过分析熵权灰关联分析法的决策模型,根据样本数据建立了熵权灰关联度分析法的煤炭种类(无烟煤,烟煤和褐煤)辨识模型,并反向检验了待测煤样识别的准确性。最后对比分析了熵权灰关联度分析法和模糊识别法的煤样识别的准确性。结果表明:熵权灰关联度分析法对建模煤样和待测煤样的识别准确率均达到100%;而模糊识别法对建模煤样、待测煤样的识别准确率分别为83.33%、75.00%,总准确率为81.25%。说明熵权灰关联度分析法泛化能力强、可靠性高,明显优于模糊识别法。     

Argentation high performance liquid chromatography of methyl esters

The technique of argentation chromatography with silver ion on a macroreticular exchange resin has been applied to high performance liquid chromatography (HPLC) to separate fatty methyl esters and their isomers. Elution of methyl linolenate from the column and more rapid separation of dienes are made possible by programming column temperature from 25 to 70 C. Samples from ca. 0.025 μ to 8 μl can be analyzed on a 2-mm id x 61-cm column. Two 7-mm id x 61-cm columns in series have been used to separate 100-μl samples into fractions for further analysis by capillary gas chromatography. Various forms of argentation chromatography have been widely used for analysis and for separation of compounds from oils and fats including hydrogenated soybean oil. This paper describes the application of argentation procedures to modern HPLC to obtain faster, more efficient separations. It also describes the application of temperature programming to give more rapid separations and to extend our previous method to include methyl linolenate and its isomers. Presented at 1980 ISF-AOCS Congeress, New York.     

Static and dynamic analysis of bonded sandwich plates

Bonded joint technique provides several advantages in comparison with traditional approaches such as welded, bolted and riveted techniques. The main goal consists in obtaining mechanical performances as good as, or even better than, a system without discontinuity or linked in a traditional way. In this paper, the static and dynamic behaviour of bonded joints has been investigated by means of various techniques. For the bonded materials, we focus on an epoxy resin and two different adhesive tapes; we performed experimental modal analysis (EMA) to validate finite element (FE) models which will be used for further finite element analysis. We also applied a damage detection methodology to locate and detect damage.     

Wettability assessment of plasma-treated PBO fibers based on thermogravimetric analysis

Changes in the surface wettability of poly(p-phenylene benzobisoxazole) (PBO) fibers were investigated by thermogravimetric analysis (TGA) following an air dielectric barrier discharge (DBD) plasma treatment. The results were then supplemented and confirmed by scanning electron microscopy (SEM), dynamic contact angle analysis (DCAA), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) measurements. After exposure to the DBD plasma at a pre-determined power level, TGA analysis showed that the residual rates retained by the PBO composites decreased, which meant an increase in the amount of resin coating the PBO fibers in the composites. Observations by SEM confirmed that there was more resin adhering to the treated PBO fibers and the wetting behavior of resin on the fibers was greatly improved. Meanwhile, DCAA for the treated fibers showed a significant enhancement in fiber surface free energy. XPS and AFM were performed in order to reveal any variations in fiber surface activity and surface morphology resulting from the surface treatment. The resulting data showed that increases in oxygen-containing polar groups and surface roughness on the plasma-treated PBO fibers contributed to the above improved wetting behavior. With comprehensive analyses, it was concluded that TGA could be used as a supporting method assessing the surface wettability of PBO fibers before and after air DBD plasma treatment.     

Study of the copper anode passivation by electrochemical noise analysis using spectral and wavelet transforms

The passivation of copper anode in sulphuric acid industrial electrolyte at 65 °C was investigated by electrochemical noise (EN) technique using three imposed anodic currents 153, 180 and 210 mA cm⁻² (galvanostatic or chronopotentiometric technique). The wavelet transforms and power spectral density (PSD) analyses have been employed to analyse the EN data. It has been found that during active dissolution the electrode surface is dominated by long time scale process and the change of the position of the maximum relative energy from D7 to D8 could be an indication of future passivation. This is associated in fast Fourier transform analyses by the disappearance of the low frequency plateau (white noise). During anodic dissolution the electrode surface was mainly undertaking general corrosion and the relative energy distribution was concentrated on large timescale crystals (D7-D8) with range of scale between 25.6 and 12.6 s. During passivation the electrode surface was dominated by short time scale process (D3), and during trans-passivation by medium (D4) followed by short time scale process (D2) with range of scale between 0.8 and 0.4 s, 1.6 and 0.8 s and 0.4 and 0.2 s, respectively. Crystals D2 and D3 could be related to metastable pitting and crystal D4 to localized corrosion.     

新型铸造用酚醛树脂粘结剂的生产工艺

苯酚、苯基苯酚、尿素与甲醛的反应产物进一步与糖醇缩聚生成新型铸造用改性酚醛树脂粘结剂。该粘结剂具有粘结强度高、低氨、低粘度等优点。其工艺技术已应用于工业生产。     

激光衍射光散射法在聚氯乙烯树脂粒度分析中的应用

主要介绍激光衍射光散射法在聚氯乙烯树脂粒度分析中的应用。并与筛分法对照,比较了两种方法测得样品的平均粒径,分布宽度,三目集中率,同时论述了颗粒形态与加工性能之间的关系。     

Chemical and petrological properties of some liptinite-rich coals from British Columbia

Chemical and petrological analyses were carried out on several British Columbia coals which are known as ‘needle’ coals because of the pine needle morphology exhibited on weathering. The object was to determine the nature of the precursor and thus to identify the component maceral as resinitic or algal. Infrared spectroscopy, saturate fraction gas chromatography, pyrolysis chromatography, gas chromatography-mass spectrometry, organic elemental analysis and reflectance and fluorescence microscopy were used. While the i.r. properties are consistent with previously published results on resinite, the other chemical results suggest that the present materials are not obviously related to any given member of the liptinite group of macerals. High concentrations of extractable hopanoid hydrocarbons are interpreted as resulting from high contribution to the biomass by bacterial debris. The petrological results suggest that the main constituent of the ‘needles’ can be best described as bituminite II or III derived from non-algal lipids. This conclusion is also supported by the observed associations of the other identifiable macerals. The results indicate that the ‘needles’ have been chemically and petrologically homogenized from a liptinite-rich precursor with minimal algal input. The present morphology may have been preserved from resin rodlets which have been severely altered by catagenetic or biological mechanisms or both.     

Torsional braid analysis of the cure of some tetra-N-glycidyl-4,4′-diaminodiphenylmethane systems

Torsional braid analysis has been used to study the curing reaction of some resin systems based upon tetraglycidyldiaminodiphenylmethane. TBA gives isothermal times to gelation and vitrification and hence the processing window for the particular systems studied at any intermediate isothermal temperature. The activation energies for the processes involved were also derived allowing extrapolation outside the range of the experiments.     

基于投影寻踪的灰色聚类分析在 煤样识别中的应用*

煤炭种类识别是一个非线性灰色系统,鉴于煤样特征指标较多、其意义、量纲不同,且在数量上差异较悬殊,选用了灰色定权聚类评判模型。因指标权重对模型评判结果具有重要影响,采用了投影寻踪法计算出各指标的客观权重,以此求出煤样隶属各灰类即无烟煤、烟煤及褐煤的聚类系数。分析表明用基于投影寻踪算法的灰色定权聚类分析识别煤样种类完全可行。     

Thermal and mechanical analysis of pickled and tanned cowhide: Effect of solar radiations

Cowhide, a natural biopolymer of collagen, forms raw material for leather, biomaterials, and food, among others. Thermal and mechanical analysis was done using dynamic mechanical analyzer. Effect of tanning and natural solar radiations on the storage modulus, tan δ, and thermal stability of pickled and tanned cowhides has been investigated in the temperature range of 30–240°C. Tanning has been shown to enhance thermal stability and storage modulus. However, tanning decreases its dissipative capability. Thermal stability of both tanned and pickled hide decreased with time of exposure to irradiation. Storage modulus dropped drastically within the initial 6 h of natural solar radiations before rising progressively with the subsequent 12, 18, and 24 h, although still lower than that for nonirradiated sample. Thermal–mechanical analysis proved to be a useful technique for assessing effect of tanning and natural solar radiations on cowhide. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43208.     

某电厂凝结水精处理混床下布水板损坏分析

某电厂2×1 000 MW新建机组,凝结水100%通过精处理,精处理再生方式为高塔法。在调试过程中发现,1#机组凝结水精处理系统1#混床下布水板损坏,针对该问题,进行了原因分析及比较,并最终予以解决。诱发该问题的原因相对较隐蔽,因此问题的分析及解决具有一定的借鉴意义。