IN-LINE MEASUREMENT OF THE REFINING EFFECT-AN IMPORTANT NEW TOOL FOR USE IN THE PULP AND PAPER INDUSTRY

ABSTRACT

In the production of paper, pulp fibers are put through a refining stage. This greatly enhances the fiber characteristics and the resulting quality and properties of the paper that is being produced.

This paper outlines the various detailed processes which occur during the refining stage and what the resulting effects are on paper quality. It discusses the measurements of 'freeness’ and 'drainage rate’, which are used today as the primary means of measuring the'refining effect’, and provides a brief evaluation of the effectiveness and limitations of these techniques.

With the Scanning Laser Microscope, one can now observe the 'refining effect’ on a microscopic basis by analyzing the structure of individual fibers. In particular one can measure the changes in the mean fiber diameter and the amount of fines that are produced. These changes are measured on a statistically significant basis in real time and provide valuable information for control of the refining process itself.

This paper reports actual test results and provides a preliminary analysis of the significance of these results and how the findings could best be implemented in an actual control strategy for operating a refiner.     

铜及铜合金带材导电率的涡流测试方法

采用涡流法选择不同的测试频率,分别对不同厚度不同叠加层的几种铜带材进行了导电率测试试验,并与双电桥法进行了对比。结果表明,只要测试频率和叠加层数合适,用涡流法完全适合对铜及铜合金带材进行导电率测量,非常适用于规模化生产铜及铜合金带材导电率快速检验的需要。     

REVIEW OF NEW PROCESS TECHNOLOGIES IN THE ALUMINUM DIE-CASTING INDUSTRY

There have been many challenges in aluminum die casting to establish casting processes to produce high-integrity components from aluminum alloys. Advances in new casting technology mainly have been in pressure die casting; in particular, to obtain mold filling at low speed. This can be achieved by using innovative filling processes with aluminum alloys in the liquid or semisolid state. Different techniques such as high-pressure die casting (HPDC), Cosworth process, low-pressure systems, squeeze casting, indirect squeeze casting, metal compression forming (MCF), and semisolid metal (SSM) processing have been developed. Semisolid forming includes thixoforming and rheoforming. During the semisolid casting process, preheating by induction is needed to obtain the same temperature and the same liquid fraction through the billet in a short time. Thixocasting in the semisolid state helps to avoid turbulence during mold filling.     

INVERSION OF THE STRAIN-LIFE AND STRAIN-STRESS RELATIONSHIPS FOR USE IN METAL FATIGUE ANALYSIS

Abstract— Two methods are described for inverting the strainrange/life and strainrange/stressrange equations commonly used in fatigue analysis in order to obtain closed-form expressions for life and stressrange in terms of strainrange. In the Collocation approach the form used is N _f= A (Δε—Δε₀)γ or N _f= A (Δε)Ψ(Δε—Δε₀)γ. In the Spline-Function approach the curve is divided into two regions. At strainranges above where the elastic and plastic lines intersect the equation is N _f= N _T R ^1/c exp δ R α; at lower strainranges it is N _f= N _T R ^1/b exp δ R β, where N _T is transition life, R is strainrange normalised to transition strainrange, and b, c , α, β, δ are constants determinable from the constants of the equation to be inverted. Similar expressions are derived for the cyclic stress/strain curve in terms of the same constants. The methods are illustrated by an example, and found to have close conformity to the basic equations to be inverted.     

测量不确定度的评定和表示方法：——“测量不确定度表示导则（ISO：1993E）”简介

介绍了正确表示测量不确定度的意义、国际“测量不确定度表示导则”的使用范围，不确定度的定义和基本概念，不确定度的评定方法和表示方法以及报告测量不确定度的要求。旨在宣传并促进国际“测量不确定度表示导则”的推广应用。     

MEASUREMENT OF MENTAL WORK LOAD AND OF ACCEPTABLE LOAD: POSSIBLE APPLICATIONS IN INDUSTRY

In experiments to assess mental work load the effect of the central choice making system being the weakest link is demonstrated, using a binary choice generator. It was found that increasing the number of binary choices per minute diminished the irregularity of the rest pattern (Sinus Arrhythmia) without affecting the level of heart rate.

A simple scoring method for the use of sinus arrhythmia is put forward and different tasks are scaled according to the progressive suppression of sinus arrhythmia. Referring to experiments showing that the central choice making mechanisms are operating as a single channel, the “method of distraction stress” is introduced. The deterioration of experimental performance by this method is described and compared with the deterioration caused by other sources of stress.

Finally the concepts of reserve-capacity and “willing-to-spend” capacity are discussed.     

氙离子推力器放电室等离子体参数测量

论述了离子推力器的工作过程,同时介绍了静电探针的测量原理,设计制作了用于诊断离子推力器放电室等离子体特性的双探针测量系统.装置用于氙离子推力器放电室等离子体测量,获得了放电室等离子体参数(电子温度、离子密度等)与推力器工作参数之间的变化关系.     

THE USE OF A NEW LINE-SPRING SHELL ELEMENT FOR ELASTIC SURFACE CRACK ANALYSIS

In this paper, the Line-Spring concept developed by Rice and Levy[l] is used to build a new elastic surface cracked shell element in the general purpose Finite Element code CASTEM 2000. The implementation is described and an energy release rate technique is proposed to arrive at more accurate Stress Intensity Factor values at the crack front-free surface intersection. A comparison with existing accepted numerical solutions is made on various plane and cylindrical configurations and a discussion on the applicability of the model is presented.     

NEW APPROACH FOR ESTIMATION OF ΔJ AND FOR MEASUREMENT OF CRACK GROWTH AT ELEVATED TEMPERATURE

Abstract— The ACPD-method was used to measure crack growth in low cycle fatigue tests at elevated temperature. The material which was investigated at T = 550°C was the ferritic steel 2.25Cr–1Mo. Characteristic values of representative hysteresis loops were determined. The crack growth data were correlated with the effective part of the fracture mechanics parameter Δ J. A new method for the calculation of Δ J is proposed.     

世纪之交展望我国的碳纤维工业

我国研制碳纤维至今已有三十余年历史 ,并初步建成工业雏型 ,为国防现代化和国民经济的发展做出了积极贡献。但是 ,至今仍处于中试放大阶段。其首要原因是PAN原丝质量没有真正过关 ,工程化开发没有取得重大突破 ,应用基础研究创新甚少。此外 ,资金投入力度不足 ,导致与国外先进水平约有 1 5年左右的差距。在世纪之交展望我国的碳纤维工业喜忧参半 ,任重而道远。     

聚丙烯结晶度测试方法的对比分析

用差示扫描量热(DSC)法、广角X射线衍射法(WAXD)和密度法对三种不同等规聚丙烯(iPP)的结晶度进行了测试研究,并对结果的差异原因进行了对比分析.结果表明,不同测试方法或数据处理方法所测得的结果相差很大;所测三种iPP的结晶度大小规律是:均聚PP最大,乙-丙嵌段共聚PP居中,乙-丙无规共聚PP最小;在表征不同种类PP结晶度差异方面,DSC法最灵敏,其次是WAXD法,密度法较差.     

冷轧薄板m值的测试与分析

采用速度突变法、等应变速率拉伸法测定了应变速率敏感指数(m值)。探讨了拉伸速度的变化和变形程度对m值测试结果的影响。结果表明，增加试验速度，使m值测试结果提高。在相同的试验条件下，对不同材料的m值进行了测试分析。     

测量空间液体量的原理,方法和技术（一）

以应用于空间液体量测量为目的，详细研究了液体测量的一般性原理和方法原理，讨论了各测量原理在空间应用的可行性和可能性问题。对空间应用液体系统进行了模型分类，分析评述了先进空间液体量测量技术与系统模型的适用性。     

THE USE OF SCRIBED GRIDS FOR THE EXAMINATION OF PLASTIC STRAIN DISTRIBUTIONS IN METAL CUTTING

The deformation of grids scribed on the workpiece surface after passage of the material into the chip may be studied in association with the predictions of some appropriate theory. Such a theory based on the assumption that the workpiece material is deformed solely by simple shear is developed in this paper.     

材料理化检验测量不确定度评定方法的研究

对于材料理化检验实验室,为提高测量不确定度评定的可靠性,就评定方法而言提出了对材料不同的检测参数应采用不同的评定方法.对金属材料力学性能检测参数测量不确定度的评定进行了探讨,从而提出,可采用直接评定法对拉伸性能和维氏硬度试验结果的测量不确定度进行评定,而宜采用综合评定法对冲击性能、布氏硬度和洛氏硬度试验结果的测量不确定度进行评定.同时指出,综合评定法能满意解决金属材料理化检测结果测量不确定度评定中的某些难点.     

铜管圆度测量结果不确定度的评定

经对铜管圆度测量中引起的重复性测量误差、计量仪器最大示值误差及其分辨率和环境因素等对测量结果带来的不确定度分析,提出了测量仪器的选择和校准及测量人员的培训是至关重要的。     

用于真空测量的场发射阴极制备及研究进展

主要回顾了近半个世纪用于真空测量的多种场发射阴极,阐述其制备方法及应用现状,说明了各种阴极结构的特点,最后介绍了近几年场发射阴极制备研究的最新进展。新型场发射阴极,对于真空测量的未来发展具有重要的推动作用。     

布氏和维氏硬度压痕的正确测量

布氏和维氏硬度压痕的测量误差对布氏和维布硬度值影响很大，为了减少压痕的测量误差本文提出正确的测量方法供硬度试验人员参考。