Eight hyper cross-linked polymers based on tetrakis(4-ethynylphenyl)germanium and tetrakis(4-ethynylphenyl)methane are presented. After investigation of their N2 adsorption properties at 77 K, the porosity of the germanium-based porous organic polymers (POPs) was modulated under acidic conditions, offering an easy and direct way, in a single step, to tune the adsorption properties.

Porous shallow-water models (porosity models) simulate urban flood flows orders of magnitude faster than classical shallow-water models due to a relately coarse grid and large time step, enabling flood hazard mapping over far greater spatial extents than is possible with classical shallow-water models. Here the errors of both isotropic and anistropic porosity models are examined in the presence...

Biyad Formation is mainly made up of clastic sediments that contain substantial amount of proven crude oil in the eastern Yemen. The Byiad clastic is divided into Upper and Lower Biyad clastic units. Several vertical wells have been drilled and penetrated this formation. This study is concerned with the petrophysical evaluation by means of well log data of the Lower Cretaceous rocks at the East...

This work focuses on the occurrence of the first Hopf bifurcation, corresponding to the transition from steady to unsteady flow conditions, on 2D periodic ordered and disordered non-deformable porous structures. The structures under concern, representative of real systems for many applications, are composed of cylinders of square cross section for values of the porosity ranging from 15% to 96%....

In this paper, the effect of microstructure on the thermal conductivity of plasma-sprayed Y2O3 stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) is investigated. Nine freestanding samples deposited on aluminum-base superalloy are studied. Cross-section morphology such as pores, cracks, m-phase content, grain boundary density of the coated samples are examined by scanning electron microscopy...

Sound propagation i gas-filled capillary-tube-type orous media was investigated. The capillary tubes were taken to be nominally straight with very small pores in the walls of the capillary tubes. The complex wave number and the characteristic mpedance of such media were evaluated. Application to ceramic samples having capillary pores with square cross sections and porous walls is developed as a...

The drive toward increased semiconductor device densities and improved performance has set in motion the search for low-dielectric-constant materials. While introducing porosity in silica holds promise for reducing the dielectric constant, it remains elusive how to accomplish this without seriously degrading the thermomechanical performance. This article demonstrates a contemporary protocol for...

Many casting defects, which cannot be eliminated by changes to tooling and process parameters, can be attributed to poor design of the part with respect to manufacturability. One such common defect is shrinkage porosity occurring at casting junctions. We present a generic classification of 3D casting junctions in terms of the number, thickness and cross-section of converging elements (walls), a...

Cortical bone contributes the majority of overall bone mass and bears the bulk of axial loads in the peripheral skeleton. Bone metabolic disorders often are manifested by cortical microstructural changes via osteonal remodeling and endocortical trabecularization. The goal of this study was to characterize intracortical porosity in a cross-sectional patient cohort using novel quantitative comput...