Change in lubricity of oils with detergent additives in the course of aging

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 10, pp. 13–16, October, 1992.     

Principles for evaluating the state of a used motor oil

Translated from Khimiya i Tekhnologiya Topliv i Masel, No. 4, pp. 22–24, April, 1992.     

Numerical and experimental study of a nonisothermal turbulent jet with a heavy impurity

Temperature and momentum distributions of the carrier phase are determined experimentally and compared to results of numerical calculations using the (k–) model.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 5, pp. 735–743, May, 1986.     

Some aspects of increasing the efficiency of the dissolving process in viscose preparation

Conclusions It is possible to considerably reduce the consumptiom of cooling energy in the dissolution stage (by 1.2 GJ/metric ton) and to raise the quality indices of viscose if it is prepared in continuous apparatus.Industrial testing of the method of dissolving cellulose xanthate at high shear velocity gradients has demonstrated the possibility of shortening the process time from 4 to 1.5–2 h.Translated from Khimicheskie Volokna, No. 6, pp. 18–19, November–December, 1989.     

Tribological,electrochemical, and spectral analysis of zinc dialkyldithiophosphates (ZDDP) of different thermal stabilities

The antiwear properties of five zinc dialkyldithiophosphates, which differed in thermal stability, were evaluated in a 4-ball machine by a preliminary wear track formation method. After testing the additives, the wear resistance of the films formed was measured by the increase in preliminary wear scar diameter over that of the additive-free oil. IR spectroscopy was then used to study the transformation products of additives after thermostatic testing at between 100 and 240°C on steel surfaces, where the interaction products were evaluated by electrode potential method. The interaction of the decomposition products of dithi-ophosphates with metal surfaces was found to be followed by a change in electrode potential. For the tested additives, a relationship is shown between antiwear effectiveness of the film on a friction track during tribological tests and the electrode potential value of the steel sample. Different parts of the relationship between the electrode potential and temperature relate to different stages of dithiophosphate decomposition measured by IR spectroscopy. It can be said that chemical modification of the steel surface which produces an improvement of antiwear properties, starts at the decomposition temperature of the dithiophosphate neutral salt.     

Local rules simulation of the kinetics of virus capsid self-assembly

Jurkat T cells undergo rapid apoptosis upon stimulation of the Fas/APO-1 (CD95) receptor. We examined the role of the mitogen-activated protein kinase (MAPK) cascade as a negative regulator of Fas-mediated apoptosis. To this end, we used both physiologic and artificial activators of MAPK, all of which activate MAPK by distinct routes. MAPK activity could be efficiently elevated by two T cell mitogens, the lectin PHA and an agonistic Ab to the T cell receptor complex as well as by the type 1 and 2A phosphatase inhibitor, calyculin A, and the protein kinase C-activating phorbol ester, tetradecanoyl phorbol acetate. All these treatments were effective in preventing the characteristic early and late features of Fas-mediated apoptosis, including activation of caspases. Our results indicate that the elevated MAPK activities intervene upstream of caspase activation. The degree of MAPK activation by the different stimuli used in our study corresponds well to their potency to inhibit apoptosis, indicating that MAPK activation serves as an efficient modulator of Fas-mediated apoptosis. The role of MAPK in modulation of Fas-mediated apoptosis was further corroborated by transient transfection with constitutively active MAPK kinase, resulting in complete inhibition of the Fas response, whereas transfection with a dominant negative form of MAPK kinase had no effect. Furthermore, the apoptosis inhibitory effect of the MAPK activators could be abolished by the specific MAPK kinase inhibitor PD 098059. Modulation of Fas responses by MAPK signaling may determine the persistence of an immune response and may explain the insensitivity of recently activated T cells to Fas receptor stimulation.     

Traffic sensitive algorithms and performance measures for thegeneration of self-organizing radio network schedules

The generation of transmission schedules for self-organizing radio networks by traffic-sensitive algorithms is described. A centralized `Traffic' algorithm that can be used as a performance benchmark is presented. Also described is a distributed `degree' algorithm that is a traffic-sensitized version of an algorithm developed by A. Ephremides and T. Truong (1990). Two performance measures for comparing schedules and simulation results are also presented     

Effect of electric fields on the wear of metals in mineral oils with additives

The authors studied the mechanism of wear of friction pairs comprising similar and dissimilar materials working under the influence of electric fields in mineral oils containing various additives.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 5, No. 5, pp. 565–568, September–October 1969.