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Given the current challenges for improving the tribological behavior in automotive engines, which require lubricants that adapt to different operating conditions through replacement mechanisms to reduce friction and wear, this study aims to analyze the use of hexagonal boron nitride nanoparticles blended in the lubricating oil of a diesel engine. The target was to minimize frictional power losses and wear of cylinder liner surfaces to validate what was observed in laboratory and to confirm improvements in thermal efficiency.

Before the definition of the concentration to be used in a real engine environment, tests of sample dispersion were conducted using an ultrasound bath. The mixtures were added to storage bottles in concentrations of 0.1% and 0.5%, as observed in Figure 1. The samples were subsequently analyzed using the dynamic light scattering (DLS) technique. There was a reduction in the hydrodynamic size for the sample with 0.5% of hexagonal boron nitride (hBN), possibly due to sedimentation of the powder during the analysis, which supported this work to continue with the use of 0.1% concentration.

The behavior of hBN as nano additive in a real diesel engine was problematic when compared with laboratory environment, leading to impact in oil temperature. In addition, it was noticed a high amount of deposit formation at the top dead center (TDC) and mid-stroke (MC) and nonsignificative wear at MC and bottom dead center (BDC) of the cylinder, with unusual formation of products from antiwear additives known as zinc dialkyl-dithiophosphate at MC position with the use of hBN. For this reason, this work provides insights into how hBN nanoparticles may not contribute toward the improvement of tribological performance.

The findings of this work aimed to provide a better understanding of the impact of hBN nanoparticles used as additives in real engine environment in terms of performance and tribological impacts. The results of this work indicated that hBN as additive gave poor results in terms of performance and wear prevention.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2024-0047/

In 2014, the city of São Paulo began to implement the public policy “WiFi Livre SP.” This policy created the infrastructure for a WiFi network providing unrestricted internet connectivity in a 120 public squares, distributed in 5 geographical regions of the city (center, south, north, east, and west). In order to monitor the effectiveness of this public policy, a series of surveys were administered to users. The survey ascertained their views about the quality and frequency of the signal in the public squares.

To carry out analysis of this service a survey was used. The researchers camped out in the squares and flagged people down asking whether they could participate in the survey. Data was collected between August and October 2015, using an application for tablets developed by the research team.

The data showed that the networks functioned effectively and provided good service to the users. Another positive factor is the good signal evaluation in the public squares, since it was an initial concern of the project makers. Further, access to these networks made it possible for residents to use several platforms to communicate in an intensive fashion.

The findings show that a connectivity policy should be geared toward promoting the right of all citizens to access the internet regardless of their ability to pay. Free and full access without any sacrifices of privacy should be guiding principles in policy implementation.

What do people mean by corruption? Corruption was defined by Brooks in 1910 as ‘the international misperformance or neglect of a recognised duty, or the unwarranted exercise of power, with the motive of gaining some advantage more or less directly personal’.

We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.