水泥熟料粒径与强度关系的灰色分析

通过实验测定了水泥熟料的粒径分布及强度。用灰色系统理论的方法分析计算了各粒级熟料的颗粒对各龄期强度的关联度。结果表明各粒级的熟料颗粒对各龄期强度的贡献是不同的。其中以１０～４０μｍ的水泥熟料颗粒对各龄期强度贡献最大，小于１０μｍ及大于８０μｍ的熟料颗粒对强度的影响较小。所得结果对生产实践具有一定的指导意义。     

国债发行规模影响因素的灰色关联度分析

本文引进了一种新的多因素分析法──灰色关联度分析，对影响国债发行规模的影响因素进行分析，并将灰色关联度分析与传统分析方法──相关和回归分析──进行了比较，并由此得出几点启示．     

麦蚜天敌捕食强度的灰色评判

利用灰色局势决策理论,对两种麦蚜的优势种天敌作了灰色评判。结果表明,从捕食强度来看,小麦的孕穗期至腊熟期阶段,麦长管蚜与麦二叉蚜的优势种天敌依次为：龟纹瓢虫,草间小黑蛛和八斑球腹蛛。     

大气环境质量预测与评价的灰色定量刻划模型

本针对大气环境系统中的灰色性，运用灰色系统理论对大气环境质量进行预测与评价．该理论与方法应用于临川市大气环境质量预测与评价中，结果令人满意。     

基于GFM-VAR的我国通用航空产业演进阶段识别及政策强度有效性分析

为揭示通用航空产业系统演化的动态和有序规律,挖掘产业形成和可持续发展的阶段识别证据,针对产业演化数据的信息不完全和连续聚类特性,基于灰色系统理论和最优分割理论构建通用航空产业演进阶段识别的灰色生成序列最优分割模型(Grey sequence generation-Fisher Model,GFM),并运用VAR模型分析通航产业政策强度的有效性。首先运用灰色系统理论的(位置加权)几何平均强化缓冲算子(W)GASBO((Weight)Geometry average strengthening buffer operator)扩张演化数据波形特征并生成灰色序列矩阵;运用最优分割理论的组内离差平方和最小判断原则判定通用航空产业演化的有序递进阶段;然后,通过我国2004~2013年通用航空产业演进阶段的实证研究,发现:我国通用航空产业演化以2010年为分界点,先后经历了初创和成长两个阶段;基于VAR模型的脉冲响应函数确定我国通航产业政策强度受“倒逼出台”、“时滞限制”的影响呈弱有效性;基于政策强度(WGASBO算子)的灰色生成序列最优分割模型更有效、更具有可行性。     

灰色关联分析方法在板料抗皱性影响因素研究中的应用

应用灰色关联分析方法进行板料参数对抗皱性的综合影响研究，得到较为满意的结果。与通常的统计回归方法相比，这种方法具有计算简单、客观真实等优点．     

α-因子缓冲算子的构造及其性质的研究

为了解决灰色预测模型中的随机挠动序列问题,本文在灰色系统理论以及灰色预测建模技术的基础上,通过梳理历史文献的研究结果,提出了一个具有缓冲作用强度可调整的新型缓冲算子,即α-因子缓冲算子,该算子具有强度可调整、形式统一、预测结果优良等特性.具体来说就是通过调整强度系数可以改变其缓冲作用的强度大小、形式上兼顾了弱化缓冲算子和强化缓冲算子的统一性、在一定范围内的应用中预测结果优于其他的缓冲算子.实证的结果的确显示出了这些优良性质.     

大气环境质量预测与评价的灰色定量刻划模型

本文针对大气环境系统中的灰色性，运用灰色系统理论对大气环境质量进行预测与评价．该理论与方法应用于临川市大气环境质量预测与评价中，结果令人满意．     

基于灰色关联分析的广东省GDP与产业结构之间的关系及GDP预测的数学模型

利用灰色关联分析方法,分析了广东省GDP与产业结构之间的关系,得出了第三产业对广东省GDP影响最大,房地产业对第三产业影响最大的结论.通过建立灰色预测模型,对未来几年的广东省GDP进行了预测.     

利用数理统计方法研究冷芯盒法型芯强度与工艺因素的关系

本文介绍利用正交试验、方差分析及回归分析综合研究混砂时间、粘结剂量及通催化气时间对冷芯盒法型芯强度的影响，确定了这三个工艺因素对强度影响的显著程度及与强度关系的回归方程式，并对回归方程进行了实验验证。     

Composite mix design in the production of asbestos/cement pipes

A mathematical model is presented for the determination of optimal mix of asbestos fibres to satisfy a set of desired pipe properties which vary with pipe size, class, and material availability. The approach utilizes a linear/separable programming model which is aimed at minimizing the total cost of fibres used. The fibre properties, such as reinforcing strength, processability, and length as well as cost and stocks available are taken into account in the model. Also represented are the profile of the ideal mix relative to the required composite strength, processability, and ‘dust content’. Asbestos mixes designed using the model have been implemented in the production of asbestos/cement pipes in one of the asbestos/cement pipe manufacturing plants in the Gulf area. Optimum model mixes have demonstrated significant technical and economic merits over the conventionally designed mixes.     

Statistical aspects of the failure of organic-fiber-reinforced plastics

Conclusions Dispersion of the strength of filaments and of the Weibull coefficient leads to a drop in strength of a strand compared with the strength of the components when the adhesion by gluing together does not amount to 2–5%. The drop in strength is determined by the dispersion of strength which depends on the length of the tested specimens.Gluing together of the fibers in filaments changes the nature of the load diagrams - of a filament when its length exceeds ₀. A consequence is that the mechanism of rupture of the strand changes, and this leads to an additional drop of its strength. When specimens are 500 mm long, the drop in strength of the strand compared with the mean strength of the filaments amounts to 10%.Because of the dispersion of the Weibull coefficient, the strength of filaments does not correspond exactly to the strength of the microplastic obtained from these filaments. When there is dispersion of the strength of the filaments, failure of the plastic proceeds by failure of the microplastics as a whole.Gluing together of fibers has a double effect on the strength of the material: increased degree of gluing together of the fibers reduces the noneffective length from ₀ to 0.4–0.5 mm, and this leads to an increase of approximately 50% of the strength of the microplastic; increased gluing together leads to a change in the mechanism of failure of the strand and of the organic-fiber-plastic made from it if there is dispersion of the strength of the component filaments, and this reduces the strength of the material in accordance with (3) (by 12–14% in our case). The longitudinal instability of the properties of the filament leads to an additional drop in strength of the material by 4.5%.Translated from Mekhanika Kompozitnykh Materialov, No. 6, pp. 1011–1017, November, 1984.     

Effect of ultrasound on the properties of a glass-reinforced plastic

It is shown that removing paraffin size from the glass strands by means of ultrasound has little effect on their strength, improves the structure of the material, and raises the mechanical strength of the GRP by 11–12%. An ultrasonic strand cleaner employing focusing piezoelectric ceramic transducers is described.Institute of Mechanics, Academy of Sciences of the Ukrainian SSR, Kiev. Translated from Mekhanika Polimerov, No. 3, pp. 546–548, May–June, 1969.     

Micromechanical modelling and two-scale simulation of epoxy/glass composites with interphases and interfaces

Composite systems consisting of glass fibres and epoxy matrix with interphases and interfaces will be considered in the modelling approach. The interphase forms the transition zone between the epoxy matrix and the glass fibre. The interface is the layer between the glass fibre and the surrounding interphase. The macroscopic strength of the composite material is intrinsically related to the bond strength of the polymeric/solid interface and the micromechanical characteristics of the three phases (epoxy, glass and interphase). Homogenization is an appropriate methodology to link these two scales to predict the overall physical behaviour of the composite. The nonlinear behaviour of amorphous polymers, cohesive interface elements and the elastic behaviour of glass fibres as part of the considered composite material are presented, as well as a representative example to show the necessity of taking interface influences into account. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Modeling of fiber-reinforced PMMA at different scales

This paper deals with the modeling of fiber-reinforced PMMA. Focus is on the macroscopic mechanical response with emphasis on the fracture properties such as the ultimate strength and the fracture energy. In order to capture the macroscopic mechanical response of PMMA, a finite element formulation is presented. While the elastic response of the fibres and that of the surrounding matrix are modelled in standard manner, i.e., by standard bulk material models, the relevant failure modes such as cracking of the fibres are accounted for by means of the so-called Strong Discontinuity Approach (SDA). Since the fibres are relatively small, their fracture mechanical properties crucially depend on their geometry, i.e., they show a pronounced size effect. Based on numerical analyses of fibres with different geometries, the aforementioned size effect is naturally incorporated into the formulation [1]. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A study of the physicomechanical properties of carbon fibers at high temperatures

Conclusions 1. Carbon fibers, similar to graphite materials, are heat-resistant and do not Iose their short-term tensile strength in the temperature range studied — 20 to 2000°C.2. Young's modulus of carbon fibers hardly changes in the temperature range 20 to 1200°C, but a significant decrease is observed upon a further increase in temperature.Translated from Mekhanika Polimerov, No. 4, pp. 626–630, July–August, 1977.     

Fracture of fiber-reinforced materials

The fracture behaviour of fiber-reinforced materials is studied in this paper. Using a simple shear lag model, which includes friction at the debonded interface and the Poisson contraction of the fiber, the fiber-matrix debonding problem is solved. This gives the relationship between debonding load and debonded length. Interfacial friction is shown to have a significant effect on the debonding load. The fracture toughness of fiber-reinforced materials due to fiber debonding, frictional dissipation at fibre-matrix interface following debonding and other micro-fracture mechanisms is discussed with reference to strong and weak fibres. Finally, the strength and toughness of short fibre-reinforced materials are given.On leave from Harbin Shipbuilding Engineering Institute, Harbin, China     

Effective medium model for flow through beds of porous cylindrical fibres

We have used effective medium model for beds of circular cylindrical porous fibres in order to estimate the overall bed permeability (OBP). It is assumed that a representative circular porous cylindrical fibre is inside a fluid envelope beyond which effective medium is used. Both inside the cylindrical fibre and in the effective medium, Brinkman equation is used, however of different permeabilities and in the fluid envelope Stokes equation is used. The OBP corresponding to the porous fibres is estimated when the flow direction is perpendicular to the axis of the cylindrical fibres as well as parallel to the fibres. This in turn is used to estimate the OBP corresponding to a collection of porous cylindrical fibres that are randomly oriented. We have compared the results with some existing literature.     

A procedure for measuring the flexibility of single wood-pulp fibres

A way of determining the flexibility of wood-pulp fibres is developed, which involves i) a precise measurement of the topology of single-fibres by using a confocal laser scanning microscope and ii) the measurement of the elastic modulus of the fibres by using a single-fibre fatigue cell. Reported in this paper are the initial results of tests carried out on black spruce fibres, which have been subjected to three different levels of mechanical refining energy, namely ∼1100, 2300, and 3500 kWh/t. It is found that the fibre flexibility rises significantly between the first and second energy levels, but it does not change to the same degree between the second and third ones. The described procedure of measuring the flexibility of fibres may be used to establish the appropriate refiner energy necessary for the production of a specific grade of paper. Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 1, pp. 115–128, January–February, 2006.     

On the Hausdorff dimension of fibres

It is well known that there are planar sets of Hausdorff dimension greater than 1 which are graphs of functions, i.e., all their vertical fibres consist of 1 point. We show this phenomenon does not occur for sets constructed in a certain “regular” fashion. Specifically, we consider sets obtained by partitioning a square into 4 subsquares, discarding 1 of them and repeating this on each of the 3 remaining squares, etc.; then almost all vertical fibres of a set so obtained have Hausdorff dimension at least 1/2. Sharp bounds on the dimensions of sets of exceptional fibres are presented. Partially supported by a grant from the Landau Centre for Mathematical Analysis.