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The purpose of this paper is to synthesize and characterize a series of alicyclic two-component waterborne polyurethane (2K-WPU) which is composed of non-ionic polyisocyanate aqueous dispersion and hydroxyl aqueous dispersion.

The appearances of aqueous dispersions and 2K-WPU films were observed by photographs. The micromorphology of alicyclic polyisocyanate aqueous dispersion was examined by scanning electron microscopy (SEM). The molecule structures of WPU were studied by Fourier transform infrared (FTIR). The effect of NCO:OH molar ratio of two components and trimethylolpropane (TMP) content on the thermal stability, mechanical and water resistance properties of 2K-WPU films was studied.

It was found by SEM that alicyclic polyisocyanate particles in aqueous dispersion showed a kind of spherical particle appearance, in which hydrophobic polyisocyanate was encapsulated by hydrophilic ether linkages segment. FTIR showed that WPU was polymerized through mixture of polyisocyanate component and hydroxyl component and increasing NCO:OH molar ratio of two components from 1.1:1 to 1.5:1 had increased the content of urea, urethane and allophanate of 2K-WPU films. Increasing NCO:OH molar ratio had improved the mechanical and thermal properties of the 2K-WPU film, but the water resistance of the 2K-WPU film increased first and then weakened. Increasing TMP contents from 1 to 0.75 mol for 1:5 system had improved the mechanical, thermal and water resistance properties of the 2K-WPU film.

The investigation established a method to prepare alicyclic 2K-WPU which is composed of non-ionic polyisocyanate aqueous dispersion and hydroxyl aqueous dispersion. The prepared 2K-WPU film could be applied in the field of waterborne surface coating, e.g. textile, wood and synthetic leather surfaces (Hasan et al., 2017; Akindoyo et al., 2016).

The paper established a method to synthesize alicyclic two-component 2K-WPU. The effect of NCO:OH molar ratio and TMP content on the thermal stability, mechanical and water resistance properties of 2K-WPU films were studied.

A comparative characterisation of selective laser sintering (SLS) mechanisms of single‐ and two‐component powders is presented. The effects of the volume fraction of liquid phase and the powder absorptance were discussed. Single‐component Ni‐alloy, Fe and Cu powders as well as two‐component powder systems based on Ni‐alloy, Fe and Cu were investigated. In particular, the following types of two‐component powder systems were studied: Ni‐alloy‐Cu and Fe‐Cu powder mixtures as well as Cu‐coated Ni‐alloy powder and Cu‐coated Fe powders. SLS experiments were performed with a CW‐ Nd:YAG laser (λ=1.06 μm). The acting mechanism in all cases was liquid phase sintering.

In this research, recycled fibres (RF) were used to produce three types of two-component yarns such as cotton covered by RF "R-C" core yarn, RF covered by cotton "C-R" core yarn, and randomly blended "mixed" yarns. In the case of "R-C" and "C-R" core yarns, the core component is perfectly covered by sheath fibres and the appearance of these yarns is the same as that of yarns made with sheath fibres. The results show that "R-C" yarns are stronger than other types, while; there is no significant difference between the strength of "C-R" and "mixed" yarns. Also, the strength of all types of two-component yarns is higher than that of 100% RF yarns, while their elongation is almost as same as that of 100% cotton yarns, which are lower than that of RF yarns. Also the irregularity of all of the twocomponent core yarns is better than that of RF yarns. From the results, we conclude that, with our techniques, we can produce on a friction spinning machine two-component core yarns and blend yarns from staple fibres with acceptable appearance and tensile properties.

The purpose of this paper is to determine a nearly optimal inspection sequence for a series system consisting of two components subject to gradual deterioration and whose failures are not self-announcing and can be detected only through inspection.

The problem is tackled in the context of condition-based maintenance (CBM) with a maintenance model in the class of the control-limit policies for which the maintenance decision is made following inspection by comparison of the deterioration level to critical thresholds. A mathematical model is developed to express the total expected cost per time unit as a function of the inspection instants.

For any given series system composed of two components with known critical deterioration threshold levels, and for any given set of costs related to inspection, inactivity due to failure, and preventive and corrective replacements of each component, a nearly optimal inspection sequence of the system is derived such as the total expected cost is reduced.

Due to the complexity of the cost model with the inspection instants (×1, ×2, ×3, …) being the decision variables, it has not been possible to derive the optimal solution. A quasi-optimal sequence of inspection times is derived along with the corresponding total average cost per time unit.

In many practical situations in which CBM is implemented, a tradeoff between inspection costs and inactivity and replacement costs has to be balanced when determining the intervals between successive inspections at which the degradation level of the components should be assessed and compared to predetermined critical threshold levels. Inspecting too often would increase inspection costs but in the same time it would also increase the probability to avoid a failure and end up with a preventive replacement, whereas not inspecting often enough would increase the probability to end up with a failure increasing replacement and inactivity costs.

While the inspection problem has been largely treated for single component systems, inspection policies become much more complex when considering multi-component systems. A two-component series system is considered in this paper.

The purpose of this paper is to provide a new method to estimate the reliability of series system by using a discrete bivariate distribution. This problem is of great interest in industrial and engineering applications.

The authors considered the Basu–Dhar bivariate geometric distribution and a Bayesian approach with application to a simulated data set and an engineering data set.

From the obtained results of this study, the authors observe that the discrete Basu–Dhar bivariate probability distribution could be a good alternative in the analysis of series system structures with accurate inference results for the reliability of the system under a Bayesian approach.

System reliability studies usually assume independent lifetimes for the components (series, parallel or complex system structures) in the estimation of the reliability of the system. This assumption in general is not reasonable in many engineering applications, since it is possible that the presence of some dependence structure between the lifetimes of the components could affect the evaluation of the reliability of the system.

Despite the current dynamism in the education sector that was manifested in new approaches to work that require innovative workforce, little empirical studies have been conducted on how to influence innovativeness in higher education institutions. Moreover, though studies have established a link between hope and innovative work behaviour, no study has established how hope and its two components of agency and pathways influence innovative work behaviour. The purpose of this study is to establish the influence of hope and its two components of agency and pathways on innovative work behaviour.

A quantitative cross-sectional research design was adopted in this study. The study employed hierarchical regression to test the hypothesised relationship between hope and its components of agency and pathways on innovative work behaviour using a sample drawn from public universities in Uganda in the two categories of academic and administrative staff.

The findings reveal that pathways and agency influence innovative work behaviour. The Findings also revealed that hope significantly influences innovative work behaviour over and above its individual components of agency and pathways.

The study was cross-sectional in nature and the findings may not portray a true picture of the relationship between the study variables over time as behaviour is ever changing. Further studies could carry out a longitudinal study to establish the effect established in this study at different time intervals. The results provide a more complex understanding of how hope and its two components of agency and pathways enhance innovative work behaviour.

The findings of the study provide insightful direction to managers in public universities in Uganda to consider different avenues of increasing employee hope so as to enhance innovative work behaviour. This can be done through targeted interventions like involving employees in goal setting and setting alternative means to achieve goals.

The value of this study is both empirical and theoretical. Empirically, this study is the first to establish the influence of hope and its two components of agency and pathways on innovative work behaviour in Uganda’s university setting. Theoretically, the study extends veracity of the conservation of resources theory (COR) by clarifying those employees who possess the psychological characteristics of hope exhibit innovative work behaviour. The study also extends on the theory of hope by revealing that agency and pathways influence innovative work behaviour.

Joint reliability importance (JRI) of components is the effect of a change of their reliability on the system reliability. The authors consider two coherent multi-component systems – a series-in-parallel (series subsystems arranged in parallel) and a parallel-in-series (parallel subsystems arranged in series) system. It is assumed that all the components in the subsystems are independent but not identically distributed. The subsystems do not have any component in common. The paper aims to discuss these issues.

For both the systems, the expressions for the JRI of two or more components are derived. The results are extended to include subsystems where some of the components are replicated.

The findings are illustrated by considering bridge structure as a series-in-parallel system wherein some of the components are repeated in different subsystems. Numerical results have also been provided for a series-in-parallel system with unreplicated components. JRI for various combinations of components for both the illustrations are given through tables or figures.

Chang and Jan (2006) and Gao et al. (2007) found the JRI of two components of series-in-parallel system when the components are identical and independently distributed. The authors derive the JRI of m=2 components for series-in-parallel and parallel-in-series systems when components are independent but need not be identically distributed. Expressions are obtained for the above-mentioned systems with replicated and unreplicated components in different subsystems. These results will be useful in analyzing the joint effect of reliability of several components on the system reliability. This will be of value to design engineers for designing systems that function more effectively and for a longer duration.

With the high cost of two‐component coatings and adhesives, plus the need for precise dosing and mixing to obtain the full effectiveness of such coatings and adhesives, industry is turning more and more to the latest generation of electronic dosing and mixing equipment.

The move toward Industry 4 is accelerated by the availability of affordable sensing technologies and networking infrastructure. Condition-Based Maintenance is the well-suited maintenance strategy to make use of the information available on assets condition to optimize maintenance interventions. However, devising the optimum maintenance policy requires a representative model of the maintenance system. Most of the existing research has been focusing on single-component systems. However, assets nowadays are complex and composed of many components. The modeling of multicomponent maintenance systems presents various challenges, especially if interactions between components, such as stochastic, structural, economic and resource dependencies are considered.

In this paper, we present a detailed modeling approach based on Discrete Event Simulation for nonidentical two-component systems subject to Condition-Based Maintenance considering all four types of dependencies.

The research has shown that optimizing the maintenance system without considering resource dependence led to different and better solutions. In addition, there is a trade-off between maintenance cost and asset availability, confirming the need for multiobjective optimization.

This paper outlines a modeling approach of CBM for nonidentical two-component systems considering stochastic, structural, economic and resource dependencies. A demonstration on a case study is followed where multiobjective optimization was applied to obtain the optimal maintenance policy while minimizing maintenance cost and maximizing asset availability simultaneously.

Last year Massey Ferguson Manufacturing Ltd. decided to upgrade the durability of the finish on the agricultural tractor chassis produced at Banner Lane, Coventry, by switching from conventional melamine stoving alkyds to a two‐page epoxy primer, followed by a two‐pack acrylic topcoat. Application of these two‐component materials calls for precise metering of each component and their efficient mixing in order to obtain consistent quality of finish. Additionally, the metering and mixing pump units must be easy to clean after use in order to prevent the coating hardening up within the equipment.