Search results

Interactions of different additive types for antiwear/friction modification on surfaces can be synergistic or antagonistic in nature. This paper aims to investigate whether there are interactions between different additives in the adsorption process and whether they synergistic or antagonistic. The yielded correlations will be validated with tribological experiments to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction.

In a representative study, zinc dialkyl-dithiophosphate and dithiophosphate were elaborated in combination with two different friction modifiers, a glycerol monooleate and an organic friction modifier. As base oils, mineral oil and poly alpha olefine were used. The adsorption behavior was studied via quartz crystal microbalance with dissipation using Fe₂O₃ coated quartz crystals. The tribological performance was evaluated in a ball-on-three disk tribometer. White light interferometry was used to determine the wear volume and X-ray photoelectron spectroscopy depth profiles of the tribofilms were obtained on selected systems.

The combination of dithiophosphate and an organic friction modifier (OFM) revealed a synergistic effect in terms of wear. If the initially formed films are viscoelastic, the third body formation during a tribo experiment is more pronounced and thereby wear can be reduced. As a mechanism, the adsorption of the OFM on the formed antiwear layer is proposed.

Correlating the analytical findings with performance experiments provides further understanding of the interactions between different constituents and their implications on film formation processes and wear reduction mechanisms.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0293/

Higher education institutions around the world compete with one another in the internationalization zone. One of the biggest competitions centers on the mobility of students fighting for the share from the student market pie. The Turkish higher education system, as an emerging competitor, also participates in this competition. While many studies focus on international students in Turkish higher education institutions, the literature lacks information about why Turkish institutions participate in this game, and what tools and strategies they use in this endeavor. This study examined the rationales and strategies of higher education institutions using a semistructured online survey data collected from international offices at participating institutions. Findings revealed that Turkish higher education institutions attract international students to create a multicultural environment by increasing diversity at the campus and to increase the quality of the institution. In contrast to the findings in the literature, seeing international students as institutional revenue source was not among the rationales mentioned by the participant institutions. Besides the rationales, findings also revealed the strategies institutions use for their international student recruitment. Paralleling with the trending mechanisms used worldwide, Turkish institutions use similar strategies such as participating in fairs and events, advertisement through technology, web and social media, and using agents; however, there are also unique mechanisms created by Turkish institutions including visiting parents of current international students, high school visits, and summer camps as effective strategies. Additional research, with broader scope and depth is needed to better understand the internationalization of Turkish higher education.

This paper explores the issue of design intentions versus users' reactions by conducting a post occupancy evaluation study. It introduces an assessment of the performance of Qatar University-QU campus outdoor spaces from users' perspective after it has been used and occupied for over 20 years. The assessment aims at understanding the mutual interaction process between the built environment exemplified by the physical characteristics of campus outdoor spaces and the needs of the university community exemplified by students, faculty, and staff. Therefore, the paper argues for the value of evaluating current campus outdoor spaces from users' perspective. It aims at defining problematic areas related to the utilization of current spaces-that are contrasted with the architect's design philosophy and intentions. The methodology adopted is multi-layered in nature and incorporates a wide variety of assessment techniques; including walk-through evaluation and direct observation, behavioral mapping, and survey questionnaires. The investigation reveals a number of problems that may hinder the performance of different types of QU campus users. The paper concludes that by recognizing how well university campus outdoor spaces respond to the needs of faculty, students, and staff, one can recommend ways of improving the outdoor environment necessary to facilitate the work and learning experiences of different users within the campus and the desired student-faculty interaction.