The calibration of instruments for the measurement of paper whiteness

The pulp and paper industry traditionally measures a property called ISO-brightness based on a filter function with an effective wavelength of 457 nm, but this is not a satisfactory measure of the appearance of the material. Currently there is a growing interest in determining a whiteness value based on the CIE-whiteness equation with respect both to an indoor illumination and to the standardized D65 illuminant. This is not, however, merely a question of using the relevant mathematical functions. Many papers contain fluorescent whitening agents and this means that reproducible values can be obtained only if the instruments used are adjusted so that the relative UV-content in the illumination falling on the sample is controlled to correspond to the chosen illuminant. the paper industry employs instruments with a well-defined d/0° geometry, and the relevant ISO-Standards also define a hierarchical calibration system, which enables all instruments to be calibrated with traceability to the perfect reflecting diffuser through a reference instrument. This calibration service has now been extended to include fluorescent standards assigned whiteness [D65/10°] values. This article describes the development of this calibration routine based on the absolute two-monochromator instrument at BAM, Berlin.     

Ultrasound measurement method: Errors, noise, and sensitivity

At the National Center of Aerospace Research (ONERA), the burning rate of solid propellants has been determined by means of an ultrasound technique for many years. This paper presents the results obtained on composite propellants for different initial pressures and temperatures, which allow one to discuss the advantages and limitations of the method in terms of the measurement possibility and accuracy. The sensitivity of propagation of ultrasound waves to pertinent physical parameters or operating conditions is illustrated. The errors induced by inadequate corrective terms taken into account in the measurement theory, the effect of the electronic noise of the equipment, and the procedure of differentiating experimental data are shown. Selecting suitable operating conditions allows one to reduce the instrumental error down to 1% of the burning-rate value. Though the ultrasound method is not absolutely universal and perfect, the quality of the data obtained is good enough to be noted. Translated fromFizika Goreniya i Vzryva, Vol. 36, No. 1, pp. 59–67, January–February, 2000.     

The clay mineral content of various rock types compared with the methylene blue value

The methylene blue test has been developed in France for giving an overall assessment of the clay characteristics of an aggregate. The Department of the Environment, Northern Ireland, introduced the test into a specification to indicate the soundness of basalt and gritstone aggregates—the test being carried out on finely ground samples. As the test was unfamiliar in the UK, it has been investigated. A detailed and expanded test-method has been written and 28 samples, mainly from basic igneous rock sources, have been tested. Experiments have shown that the particle size of the test-specimen affects the result (the ‘blue value’). The clay contents of the samples, and the swelling properties of the clay minerals, have been determined by X-ray diffraction of the air-dry and glycolated samples. Where the samples were of a suitable size, the water absorption has been measured. The correlations between the blue value and the following parameters are discussed: the clay content; the swelling properties; and the water absorption. It is concluded that the methylene blue test, carried out on a powdered sample, should not be used by itself to judge whether a source of aggregate should be accepted or rejected.     

表面活性剂检测方法综述

重点综述了分光光度法、两相滴定法、色谱法、薄层层析法、电化学法、共振散射法、毛细管电泳法和示波极谱法等常见的表面活性剂检测方法,对比了各种检测方法的适用条件、优点与缺点;提出表面活性剂检测方法的选择与表面活性剂的类型有关;最后展望了表面活性剂检测的发展方向。     

氯化反应产物流量测控仪表的选择

针对氯化反应产物的强腐蚀、易堵塞管道、低电导率和低流速等特性,分析了曾采用过的几种流量测控仪表的缺陷;介绍了超声流量计的工作原理及其在氯化反应产物流量测控中的优势 。     

Measurement and Assessment of Colour Differences for Industrial Use I—The Reproducibility and Repeatability of Colour-difference Measurements

The precision of measurements obtainable with several types of colorimeter (Colormaster Marks IV and V, Small Sphere Color-Eye DI, Colorcord Mk IIA, Harrison 61 and Harrison 70) for several substrates (ceramic tiles, fabrics, yarns and threads, loose stock, slubbing and plain carpet) has been studied. Several methods of preparation and presentation of the sample to an instrument are considered and the results are compared in terms of standard deviations in 1964 (CIE) units. For textile samples the most generally satisfactory technique is to present the prepared sample behind glass in a rotating head. Under these conditions a wide range of fabrics can be measured with approximately the same precision (0<1 CIE) as ceramics. For yarns and threads, carefully wound on formers, the precision is approximately 0<3 CIE, and a slightly better precision can be obtained for carpets. Values of < 0<3 have been obtained for loose stock using a special rotating head, but values for slubbing are somewhat worse (0<8–1<0). Except for the Colorcord, good between-instrument reproducibility (< 0<3 CIE) can be obtained for measurements of colour differences. For a given sample the absolute values (X, Y, Z) vary considerably with the instrument, the differences between pairs of instruments being equivalent to several CIE units and up to 19 when the Harrison 70 is used, even for measurements on a ceramic tile.     

Publications Sponsored by the Colour Measurement Committee—V The Adams—Nickerson Colour-difference Formula*

The Adams uniform-chromaticity-scale diagram, the Adams-Nickerson uniform colour space (ANLAB) and the derived colour-difference formula are described in detail. An example showing the method of calculating colour differences is given.     

Comparative sensitivity of various analytical techniques to the low-temperature oxidation of coal

A number of analytical techniques were used to investigate the low-temperature oxidation of a high-volatile and a low-volatile bituminous coal. Two oxidation treatments were used: stockpiling at a size of < 3 mm out of doors, and treating in moist air at < 420 μm in a laboratory retort maintained at 50 °C, 65% r.h. ⁵⁷Fe Mössbauer spectroscopy and computer-controlled scanning electron microscopy (CCSEM) were used to investigate the oxidation of included minerals; diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and electron spectroscopy for chemical analysis (ESCA) were used to examine maceral oxidation; and the alteration of several technological properties (Gieseler plasticity, free swelling index and coke reactivity) was also monitored. Gieseler fluidity was by far the most sensitive of these measurements to the early stages of oxidation, while the Mössbauer measurement of the oxidation of pyrite to sulphates or oxyhydroxides was the second most sensitive indicator of oxidation for the coals investigated. DRIFT and ESCA exhibited significant features derived from oxygen functional groups in macerals only after the oxidation was severe enough to have nearly destroyed the plasticity. However, band ratio techniques appear promising as a method of enhancing the sensitivity of DRIFT to oxidation.     

Relationship between electron sensitivity and chemical structure of polymers as EB resists. I. Electron sensitivity of various polyamides

Polyamides containing double bonds or epoxy groups were synthesized and evaluated as electron beam (EB) resists, in order to find the relationship between electron beam sensitivity and chemical structure of the polyamides. It was found that polyamides containing double bonds, which have good solubility, are easily crosslinked by the electron beam exposure. The sensitivity of a polyamide with 70 mol% of the repeat units containing double bonds was equivalent to that of a 100% unsaturated polyamide which contained double bonds of 100% molar ratios, and thus it is not necessary that the polyamide be a homopolymer of unsaturated repeating units. The polyamides have good physical properties, and are adaptable to dry etching processes.     

Relationship between electron sensitivity and chemical structures of polymers as electron beam resists. VI: Electron sensitivity of various acetalized poly(vinyl alcohol)s

Acetalized poly(vinyl alcohol)s which were synthesized from poly(vinyl alcohol) (PVA) and aldehyde or ketone were evaluated as electron beam (EB) resists, in order to investigate the relationship between EB sensitivity and chemical structures of the polymers. It was found that the acetalized PVAs were easily crosslinked by EB exposure. The main mechanism of crosslinking may be radical reaction at acetal group. The sensitivity of the acetalized PVA depended on the structure of the acetal group. Acetalized PVAs synthesized from benzaldehyde, in which the electron attracting group was substituted on the benzene ring and from linear aliphatic aldehyde having a long alkyl chain, had high sensitivity. A high sensitivity of 7.2 × 10⁻⁷ C/cm² was attained when the acetalized PVA synthesized from p-chloro-benzaldehyde was used. Acetalized PVAs synthesized from PVA and aldehyde having a cyclic structure had an excellent dry etching durability and were suitable as negative EB resists.     

现场热工仪表检定与校准方式的探索

探讨了现场热工仪表的检定或校准方法,提出了现场仪表按回路进行校准的方法、步骤以及如何计算误差。     

Study of thermal regeneration of spent activated carbons: Thermogravimetric measurement of various single component organics loaded on activated carbons

Thermogravity analysis of the activated carbons loaded with 32 different single component organics showed that TGA curves could be classified into three distinct groups with regard to their shapes. The organics that belong to Group (I) are rather volatile and TGA curves can be explained by equdibrium desorption model. Group (II) organics are relatively easy to decompose and TGA curves were interpreted in terms of first-order cracking kinetics. The parameters included in these models were obtained from the measured TGA curves by utilizing half desorbed temperature T_{$\text{1}\text{2}$} and reciprocal slope of TGA at T_{$\text{1}\text{2}$}, ΔT. Group (III) consists of phenol, β-naphtol, lignin etc. and gave high residuals on activated carbons after heating up to 800°C. This suggests that these organics are the ones that are critical to the ordinary thermal regeneration method.A rough classification of organics into these groups was done by using the boiling point and the aromatic carbon content.     

Relationship between electron sensitivity and chemical structures of polymers as EB resists. III. Electron sensitivity of various polyamides using 3-amino perhydroazepine

Homopolyamides and copolyamides containing a variety of reactive and/or stabilizing groups, such as double bonds, epoxy groups, or naphthalene moieties, were synthesized using 3-amino perhydroazepine (APA) as a diamine monomer. These polymers were evaluated as electron beam (EB) resists, in order to investigate the relationship between EB sensitivity and chemical structure of the polyamides. It was found that polyamides containing double bonds were easily crosslinked by the EB exposure and that the sensitivity of a polyamide containing double bonds in the side chain was higher than that of a polyamide containing double bonds in the main chain. The sensitivity of a polyamide containing epoxy groups was lower than that of the above. Copolymer from APA, 77 mol % of trans-3-hexenedioyl chloride (HC) and 23 mol % of 2,6-naphthalenedioyl chloride (NC) had the same EB sensitivity as that of the homopolymer from APA and HC. The polyamides had excellent dry etching durability and were adaptable to EB lithography.     

瓷枕种种

0前言就“瓷枕”二字而言,顾名思义显然是瓷质品,是供人垫头睡的东西,所谓“卧时蔫首之具也。”但是,不管用任何贵的原料制成之枕,要算木制品最早了。因为“枕”字是书“木”字边的,这显然是无疑的,其他任何类的原料制成之枕,都是在木质枕之后才产生的。而瓷质枕又是在陶质枕之     

几种典型仪表的选用

介绍了仪表的选型原则,从腐蚀形态和常用耐腐蚀材料的特性等方面,阐述了针对氯碱装置的仪表选材,并讨论了远传膜片密封系统、雷达与超声波液位计、电磁流量计等应用最广泛的仪表的选用。