http://arthra.ugal.ro/handle/20.500.14043/25381 Tue, 07 Apr 2026 16:54:50 GMT 2026-04-07T16:54:50Z http://arthra.ugal.ro/handle/20.500.14043/25395 Multipurpose Ecological Lubricating Greases Florea, Ortansa; Luca, Marcel; Matei, Vasile Lubricants facilitate the effective operation of mechanical equipment, reducing friction and wear, but, in the same time, they are a large and diffuse pollution source, both on soil and in water. Eliminating or reducing the formation of pollutants and waste pollution prevention make an important contribution to environmental protection. Conventional lubricants based on mineral oils contain toxic and non-biodegradable substances. Biodegradable lubricants are technical and environmental alternatives for conventional lubrication. Lubricating greases are considered as colloidal dispersions of a thickener in a lubricating fluid. Their biodegradable properties and their lubricating ability depend on the main components: the base oil, the thickener and the additives. The aim of this work is to find their most suitable composition to produce ecological lubricating greases with good performances and thus using them as multifunctional lubricants. THE ANNALS OF “DUNĂREA DE JOS“ UNIVERSITY OF GALAŢI FASCICLE VIII, 2010 (XVI), ISSN 1221-4590, Issue 2 TRIBOLOGY Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25395 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25394 Research Issues on Punch - Circular Plate Elastic Contacts Trandafir, Marius; Diaconescu, Emanuel Circular plates enter into the category of finite dimension bodies. Solutions regarding the displacements and stresses, which appear at the contact involving finite dimension bodies and also numerical and analytical results regarding several plates were reviewed in this study. For thin bodies and small transversal dimension bodie,s Diaconescu and Glovnea advanced analytical solutions solving a Boussinesq type problem for an elastic layer and a Boussinesq type problem for a cylindrical body. The obtained results satisfy all elasticity requirements, thus they are the searched ones. Experimental set-ups built by Glovnea and Ovcharenko, used to investigate contact problems via laser profilometry or direct optical methods, were also reviewed. THE ANNALS OF “DUNĂREA DE JOS“UNIVERSITY OF GALAŢI FASCICLE VIII, 2010 (XVI), ISSN 1221-4590, Issue 2 TRIBOLOGY Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25394 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25393 The Presence of Hydrogen as Wear Environment for the Mechanical System of the Continuous Casting Equipment Teletin, Claudiu; Spânu, Constantin; Crudu, Ion In the last years the continuous casting of the steel has a tremendous development. In the same time, the casting steel quality requirements become higher. The hydrogen as environment of the casting diminishes the steel physical and mechanical properties, that is why its concentration is monitored. Technological conditions (cooling with sprayed water, highest temperatures of 800°C...1200°C) generate ample quantities of hydrogen into the equipment environment. This penetrates and pollutes the slab and the other triboelements (rolls, moulds etc.). The presence of hydrogen has an anticipatory effect on wear of the triboelements. In the paper, the main triboelements of installation are identified and it is determined the hydrogen concentration into various areas of the cross section of the slab that is an important element of these tribosystems. THE ANNALS OF UNIVERSITY “DUNAREA DE JOS“ OF GALAŢI FASCICLE VIII, 2010 (XVI), ISSN 1221-4590, Issue 2 TRIBOLOGY Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25393 2010-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25392 Numerical Modelling of 3D Impact Stelian, Alaci; Diaconescu, Emanuel; Ciornei, Florina; Irimescu, Luminița; Cerlincă, Delia; Rusu, Ovidiu The paper presents a virtual device designed for studying tri-dimensional impact. The main goal of the work is to present a solution for finding the coefficient of restitution for the tri-dimensional case of a sphere frontally impacting a rotating cylinder. The ADAMS/View software was used to solve the problem. The validation of the problem was done by applying the software for a particular case, for which the authors have had experimentally obtained the value for the coefficient of restitution. There was found a very good agreement between the experimental data and the results obtained using the virtual model. This concordance validates the veridical results obtained using a virtual device. THE ANNALS OF “DUNĂREA DE JOS“ UNIVERSITY OF GALAŢI FASCICLE VIII, 2010 (XVI), ISSN 1221-4590, Issue 2 TRIBOLOGY Fri, 01 Jan 2010 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25392 2010-01-01T00:00:00Z