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Purpose The purpose of this paper is to understand the philosophical changes which underpin research and practices in project management. This study is an attempt to challenge previous studies that have tried to explain this change in order to provide a better explanation. Design/methodology/approach The authors adopt a critical review research method to challenge previous explanations of the paradigm change and definition of communication. For this purpose, philosophical and social theories and concepts have been used. Findings This paper proposed changing the paradigm from modernism to postmodernism and the paradigm shift, which happens from postmodernism to participation, as a better explanation for the paradigmatic change in project management. Furthermore, the important role of communication has been illustrated in the participation paradigm. Originality/value For the first time in project management, the authors attempt to clarify the role of power in this paradigmatic shift, especially because this concept is an axial concept in postmodern philosophy and a neglected concept in project management literature. In addition, communicative action theory has been used with the aim of pursuing the influence of informal power in the participation paradigm and paving the way for confronting its emerging challenges in future studies.

The remarkable resurgence of fiber metal laminates (FMLs) is certainly attributed to the hybrid properties inherent to light metals and fibers reinforced polymer (FRP). There are few reports on the role of nano-size reinforcements in these composites. In this study, the effect of graphene nanoplatelets (GNPs) on the flexural and Charpy impact properties of FMLs of aluminum (Al) 2024 reinforced with hybrid glass/Kevlar fibers-epoxy was investigated. Different wt.% of GNPs (0.0, 0.1, 0.25 and 0.5) and hand lay-up method were used to fabricate nano-FMLs followed by evaluating them in three-point bend and Charpy impact tests. Before making the FMLs, the surfaces of Al sheets were modified to generate surface pores/nano-pores in order to improve the interfacial bonding within the FMLs layers. The FMLs containing 0.1 wt.% GNPs exhibited 10%, 9% and 11% improvement in flexural strength and modulus and impact strength, respectively, compared to the FMLs containing 0.0 wt.% GNPs. Increase of the GNPs to 0.25 wt.% caused a reduction of the flexural strength and modulus and impact strength values; 13.7%, 3% and 25.5% compared to the samples without GNPs. Also increase of the GNPs to 0.5 wt.% decreased these properties to 31.3%, 8.8% and 29.5%. Scanning electron microscopy (SEM) observations of their fracture surfaces showed better adhesion at both polymer/fibers (within the FRP) and Al/FRP interfaces. However, at higher wt.% of GNPs, the FMLs became weaker and more brittle. Agglomerated GNPs at the Al/FRP interface penetrated/filled the surface pores/nano-pores on the Al surfaces. Therefore prevent the polymer penetration in pores, resulting in weak interfacial bond and thus overall weaker and less ductile FMLs. As a result, the Charpy impact values for the 0.25 and 0.5 wt.% GNPs samples were respectively 33 and 37 percent smaller than that for the 0.1 wt.% GNPs sample.

The performances of rubber-toughened polymers like acrylonitrile-butadiene-styrene (ABS) are strongly affected by the type and amount of rubber phase. Characterization of rubber phase is an effective method to predict and control the physical and mechanical behaviors of ABS materials. In this work, different methods have been employed to determine the amount of rubber phase in ABS polymers. The first method was based on thermogravimetry using a particular step degradation of the polymer. In the second method, characteristic absorption bands in the Fourier transform infrared spectra were used to make a calibration curve to determine the rubber content of unknown ABS samples. The third method was based on variation of heat capacity of ABS polymers with increasing the rubber phase content. In the fourth method, a two-step solvent extraction followed by centrifuging was used to separate the rubber particles of different ABS samples. Separation of hardened rubber particles was used to study the size and size distribution of rubber particles.

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