Absorption: The mechanism by which acoustic energy is converted into heat by friction in absorptive media. See Pack. Airborne: A noise that is transmitted by the atmosphere and can be heard outside the car. Air Cleaner Housing: The housing that retains the air filter and forces the route of combustion air through the filter medium. Air Filter: The medium that eliminates the major particulate fr...

In this paper, we obtain a necessary and sufficient condition for a conformal mapping between two Weyl manifolds to preserve Einstein tensor. Then we prove that some basic curvature tensors of $W_n$ are preserved by such a conformal mapping if and only if the covector field of the mapping is locally a gradient. Also, we obtained the relation between the scalar curvatures of the Weyl manifolds r...

Commutative properties of four-dimensional generalized symmetric pseudo-Riemannian manifolds were considered. Specially, in this paper, we studied Skew-Tsankov and Jacobi-Tsankov conditions in 4-dimensional pseudo-Riemannian generalized symmetric manifolds.

The object of this paper is to study $(epsilon)$-Lorentzian para-Sasakian manifolds. Some typical identities for the curvature tensor and the Ricci tensor of $(epsilon)$-Lorentzian para-Sasakian manifold are investigated. Further, we study globally $phi$-Ricci symmetric and weakly $phi$-Ricci symmetric $(epsilon)$-Lorentzian para-Sasakian manifolds and obtain interesting results.

Reliable measurements of air quality and emissions at large livestock buildings with inherently large spatial and temporal variations of pollutant concentrations are relatively difficult and expensive. Appropriate methodologies for such measurements are not readily apparent and techniques and strategies vary widely. Several important technical issues need to be addressed by an air pollutant emi...

commutative properties of four-dimensional generalized symmetric pseudo-riemannian manifolds were considered. specially, in this paper, we studied skew-tsankov and jacobi-tsankov conditions in 4-dimensional pseudo-riemannian generalized symmetric manifolds.

in this paper, we obtain two intrinsic integral inequalities of hessian manifolds.