Previous estimates of the microwave background anisotropies produced by freely falling spherical clusters are discussed. These estimates are based on the Swiss-Cheese and Tolman-Bondi models. It is proved that these models give only upper limits to the anisotropies produced by the observed galaxy clusters. By using spherically symmetric codes including pressureless matter and a hot baryonic gas...

Previous estimates of the microwave background anisotropies produced by freely falling spherical clusters are discussed. These estimates are based on the Swiss-Cheese and Tolman-Bondi models. It is proved that these models give only upper limits to the anisotropies produced by the observed galaxy clusters. By using spherically symmetric codes including pressureless matter and a hot baryonic gas...

Different models of universes are considered in the context of teleparallel theories. Assuming that the universe is filled by a fluid with an equation of state P=-ρ-f(ρ), for different teleparallel theories and different equation of state we study its dynamics. Two particular cases are studied in detail: in the first one we consider a function f with two zeros (two de Sitter solutions) that mim...

In this study, minor-addition elements such as Si, Co, Cr, W, Mo, and Ti were added to matrix to improve the wettability between the diamonds and Cu matrix. The pressureless liquid-phase sintering technique adopted in this study provides a low-cost method for producing diamond/Cu composites with high potential for industrial mass production. Thermal properties of the diamond/Cu-Ti composites fa...

Pin-on-disk tests were performed to evaluate the wear behaviour of a 2024 aluminium alloy metal matrix composite (MMC) reinforced with 52 vol.% TiC particles (Al-2024/TiC) in fabricated and thermal-treated (T6) condition. The MMC was produced via pressureless infiltration partially sintered preforms an average particle size 1.1 μm at 1200 °C for 2 h under flowing argon. Microstructural mechanic...

This article is the continued version of the analytical solutions for the pressureless NavierStokes equations with density-dependent viscosity [9]. We are able to extend the similar solutions structure to the case with pressure under some restriction to the constants γ and θ.

Many natural materials demonstrate ideal design inspirations for the development of lightweight composite with excellent damage tolerance. One notable example is layered architecture nacre, which possesses toughness an order magnitude higher than its constituent parts. Man-made nacre-like ceramic/polymer composites obtained through direct infiltration polymer in ceramic scaffolds have been show...

abstract infiltration process is one of the most important components of the hydrological cycle. on the other hand, the direct measurement of infiltration process is laborious, time consuming and expensive. in this study, the possibility of predicting cumulative infiltration in specific time intervals, using readily available soil data and artificial neural networks (anns) was investigated. for...

abstract infiltration is one of the most important phenomena which is affected by the soil physical and hydraulic characteristics. measurement of infiltration needs the high cost and is time consuming, therefore estimation of infiltration is necessary. also, due to variability of soil moisture, it is important to determine the appropriate model for the estimating the infiltration rate. the pres...