CONSUMER OPINIONS TOWARDS ONLINE MARKETING COMMUNICATION AND ADVERTISING ON SOCIAL NETWORKS

On the Internet, a medium that has already proven its effectiveness in marketing activities, changes take place with astonishing speed. The recent explosion of social networking applications and their number of users has captured the marketers’ attention. Companies have started to rethink their relationships with consumers and adapt to the new online world. In this virtual world of social networks the public is the key element. Consumers perceive the social network as a personal space where they control the content. They decide on their own what they want to see and share with others. Thus, in order to manage marketing communications effectively, marketers must know the consumers’ opinions towards their presence in social networks

THEORETICAL CONTRIBUTIONS ON THE SELECTION OF POSSIBLE TRIBOLOGICAL COUPLES OF MATERIALS FOR THE MANUFACTURE OF PRECESSIONAL TRANSMISSIONS

Selecting gear materials is a great challenge for engineers. Gear teeth are subject to difficult and severe loading conditions. Simultaneous action of alternating normal and tangential dynamic stresses occurs, contact deformations accompanied by sliding friction. Gears are subject to increased requirements in terms of strength, geometric accuracy, dimensional stability, and durability. For the manufacture of gears, especially from thermoplastic materials, a theoretical argumentation of the materials is needed. An extensive study of thermoplastic materials, around the world needs to be done and the most efficient tribological couples to be chosen in terms of heat transfer from the gear zone, operation with or without lubrication, and gear life. In this paper, a theoretical synthesis of the Steel / Plastic, Plastic / Plastic, Plastic/Steel tribological couples is made, which were used in conformist and non-conformist experiments. Therefore, selected tribological couples are supposed to be used in the Precessional Transmissions applications

THEORETICAL AND EXPERIMENTAL MODELLING OF THE TRIBOLOGICAL BEHAVIOUR ASPECTS OF CONTACT ELEMENTS IN THE PRECESSIONAL GEARING (PG)

This paper deals with the theoretical-experimental model of the tribological behavior of the contact elements in precessional gears (PG) in the functions of conjugate profiles of linear velocities "convex-concave" or "convex-convex" for the corresponding geometric parameters (ρk i k ρ − r) and the values of the kinematic force parameters (VE 2 , VE i Va) for each concrete position of the ki points. The calculation of the constructivefunctional and kinematic parameters of the “roller-shoe” and “roller-roller” elements of the tribocouple were adjusted for the experimental verification tests on the SMT-1 installation and adapted to the specific test conditions of the tribocouples with conformal contact of gear teeth made of plastics, which will be subjected to sliding friction and rolling processes of the concrete tribocouple elements