表面活性剂在卜特兰水泥表面上的吸附行为(英文)

实验探索了脂肪醇聚氧乙烯醚硫酸盐 (AES)、氯化十六烷基吡啶 (CPC)、β -萘磺酸聚合物 (NS)以及烷基酚聚氧乙烯醚 (TX -10 )等四种不同类型的表面活性剂在普通硅酸盐水泥表面的吸附行为。研究表明 ,AES在水泥颗粒表面的吸附是一种快吸附 ,属于LS型 ;CPC在水泥颗粒表面的吸附过程则是一种慢吸附 ,受动力学因素所控制 ;NS的吸附量与其浓度成线性关系 :TX -10则基本上不被吸附。结果显示 ,被吸附的三种表面活性剂都是疏水基朝向水相 ,增加了水泥颗粒的疏水性。然而AES随着添加量的增大 ,由于吸附胶束的形成 ,使水泥颗粒表面经由亲水 -疏水 -亲水的变化过程。从表面电荷的变化来看 ,AES、NS的添加均使水泥表面Zeta电位有所增加 ,而CPC却使得水泥颗粒表面从带负电变到带正电。文中所提出的改进Stern双电层模型能很好地说明几种表面活性剂在水泥颗粒表面的吸附特性     

Modelling multiple cohesive crack propagation using a finite element–scaled boundary finite element coupled method

This paper presents an extension of the recently-developed finite element–scaled boundary finite element (FEM–SBFEM) coupled method to model multiple crack propagation in concrete. The concrete bulk and fracture process zones are modelled using SBFEM and nonlinear cohesive interface finite elements (CIEs), respectively. The CIEs are automatically inserted into the SBFEM mesh as the cracks propagate. The algorithm previously devised for single crack propagation is augmented to model problems with multiple cracks and to allow cracks to initiate in an un-cracked SBFEM mesh. It also addresses crack propagation from one subdomain into another, as a result of partitioning a coarse SBFEM mesh, required for some mixed–mode problems. Each crack in the SBFEM mesh propagates when the sign of the Mode-I stress intensity factor at the crack tip turns positive from negative. Its propagation angle is determined using linear elastic fracture mechanics criteria. Three concrete beams involving multiple crack propagation are modelled. The predicted crack propagation patterns and load–displacement curves are in good agreement with data reported in literature.     

Toward forecasting future day air pollutant index in Malaysia

The Journal of Supercomputing - The association of air pollution and the magnitude of adverse health effects are receiving close attention from the world. The effects of air pollution were found to...     

Unearthing the determinants of Blockchain adoption in supply chain management

The behavioural intention to adopt Blockchain for supply chain management (BCSCM) is studied in this paper. The research framework adopted considers how Performance Expectancy (PE), Effort Expectancy (EE), Facilitating Condition (FC), Technology Readiness (TR), Technology Affinity (TA) and Trust (TT) can lead to the adoption of the technology. Data gathered from 157 firms is analysed using SPSS version 2 while the quality of the measurement is tested using WarpPLS. Findings revealed that FC, TR and TA have a positive influence on intention to use BCSCM and regulatory support moderates the effect of FC. This study offers valuable insights into the applicability of Blockchain technology for supply chain management.     

Feasibility of both vector control and displacement factorcorrection by voltage source type AC-AC matrix converter

This paper shows that by transforming both sides of the matrix converter to the d-q-o frames of their respective frequencies, there is significant simplification in the transformation matrix which enables the network of one side to be integrated to the other. Thus, it is possible to design for operation with field vector control on the motor side and unity displacement factor on the supply side. Laboratory experimental and digital simulation results are presented to substantiate the theory. The matrix converter used in the test is based on three modules of voltage-source SPWM converters to implement the nine switches and it has the innovative feature that the SVC voltages (for displacement factor improvement) can be derived from the zero-sequence voltages     

Indirect current control of a unity power factor sinusoidal currentboost type three-phase rectifier

The indirect current control scheme has evolved from the success of the hysteresis current controlled voltage regulated rectifier, which has been shown to be capable of: unity and even leading power factor operation; near sinusoidal current waveforms; and bilateral power transfer without the need of bi-directional solid state power switches. The advance consists of replacing the inner hysteresis current feedback loop by the standard sinusoidal PWM control and in the process saving the cost of the current measuring transducers. The scheme is evaluated through tests on 1 KW size laboratory models and through digital simulations. A theory of the system dynamics is developed and stability boundaries are presented     

Statistical inference of unsymmetrical silo pressures from comprehensive wall strain measurements

A thin cylindrical shell structure which is subjected to local or unsymmetrical loading often displays a very complex pattern of response, involving multiple alternative potential failure conditions in different parts of the structure. The loading may therefore need to be defined with great precision. In the field of silo structures, it is widely recognised that such local loads often exist, but experimental observations of the patterns of load are very difficult to obtain because of the expense of instrumentation and the need to use full-scale testing to avoid granular solid scale errors.This paper presents a newly developed technique which permits these local unsymmetrical load patterns to be determined in a much more cost-effective way. In addition, because the loading is deduced from the structural response, the method has an inherent robustness in that when the deduced loadings are generalised and used to predict a structural response, it is more likely to be close to the real response. The same cannot be said for loading patterns deduced from single discrete observations of loading with imaginative interpolations between them, which form the basis of most current design rules.The paper describes a rigorous procedure for inferring the complete pressure distribution from a large body of strain observations on the silo wall. The method is outlined and a simple practical example, involving unsymmetrical loads, is used to explore the effect of observation errors on the inferred pressures. A sample set of pressures in a specially built full-scale test silo under eccentric solids discharge is also derived.     

Fault-tolerant architecture in a cache memory control LSI

A real-time degradable four-way set-associative cache memory control (CMC) LSI is described. Three kinds of errors, address parity error, comparator error, and multihit error, can cause functional degradation by killing the associative unit corresponding to the fault detection. The parity generator and the double comparator have no effect on the timing-sensitive path delay because of the parallel configuration of the circuits. The multihit detector occupies about 16% of the propagation delay of the critical path, from the external address input to the hit/miss output