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An analytical study of vibration neutralizers

1999-10-01T00:00:00Z

Title: An analytical study of vibration neutralizers Authors: Khalil, Gazi Md.; Islam, Md. Shahidul Abstract: A machine or structure on which a steady alternating force of constant frequency is acting may take up obnoxious vibrations, especially when it is close to resonance. One method of reducing the vibration under such conditions is to use a vibration damper or neutralizer. This paper presents a detailed mathematical analysis of the principle of vibration neutralizers. The results are presented in terms of non-dimensional parameters for explaining the salient features of vibration neutralizers. It is shown that the vibration damper exercises its effect in neutralizing vibrations when its own natural frequency matches with that of the exciting force. Furthermore, the motion of the vibration neutralizer depends on the mass ratio (neutralizer mass/main mass). The higher the mass ratio the lower is its motion. Hence, an appropriate mass ratio should be chosen for keeping the motion of the neutralizer within reasonable limits. Page(s): 256-262

Preparation of dispersed silica by hydrolysis of tetraethyl orthosilicate

1999-12-01T00:00:00Z

Title: Preparation of dispersed silica by hydrolysis of tetraethyl orthosilicate Authors: Singh, T K; Jain, C L; Sharma, S K; Singh, S S Abstract: Colloidal silica particles find innumerable applications in defence and civil , such as binder for refractories, antislip agent, antisoilant, antiblocking agent, reinforcement of adhesives and molecular sieves. The present studies report utilization of monodispersed spherical silica particles for a laser project on defence applications. The material has been developed using the sol-gel technique. Role of various solvent characteristics such as dielectric constant, dipole moment and viscosity on the process are discussed. Page(s): 349-351

Asymptotic behaviour of the laminar boundary layer flow of an incompressible fluid past a flat plate

1999-12-01T00:00:00Z

Title: Asymptotic behaviour of the laminar boundary layer flow of an incompressible fluid past a flat plate Authors: Singh, B B; Verma, S K Abstract: Here the asymptotic behaviour, as the similarity variable ‘η’ tends to infinity, of the solutions of the differential equations governing the laminar boundary layer flow of an incompressible fluid past a flat plate embedded in a saturated porous medium have been studied based on the method of asymptotic integrations of second order linear differential equations. It has been found that the principal solutions exhibit asymptotic behaviour as η→∞, whereas the independent solutions do not. Page(s): 346-348

Effect of flyash addition on dielectric properties of polypropylene

1999-12-01T00:00:00Z

Title: Effect of flyash addition on dielectric properties of polypropylene Authors: Chand, Navin; Khare, Nidhi Abstract: Dielectric properties of flyash filled polypropylene have been measured at different frequencies, and temperatures ranging from ambient to 160°C. It has been found that the dielectric constant of flyash filled and unfilled poly propylene decreases with increasing frequency up to 100 kHz. The dissipation factor of pure polypropylene decreases with increasing frequency. Dielectric constant of flyash filled polypropylene increases as compared to pure polypropylene. With increasing temperature, dielectric constant (ε´) and dissipation factor (tan δ) of flyash filled and unfilled polypropylene have been measured at all frequencies between 4-100 kHz. The β́ peak position has been found to shift towards higher temperature side for flyash filled polypropylene with increase in frequency. It has also been found that incorporation of flyash in polypropylene shifts the α_c peak towards the higher temperature side. Page(s): 342-345