PURPOSE Topographic analysis of treated ceramics provides qualitative information regarding the surface texture affecting the micromechanical retention and locking of resin-ceramics. This study aims to compare the surface microstructure following different surface treatments of feldspathic porcelain. MATERIALS AND METHODS This in-vitro study was conducted on 72 porcelain discs randomly divide...

Introduction: Bone, as a hard biological tissue, consists of cells resided in the bone matrix, which is made by an organic (primarily collagen (90%) and 10% amorphous ground substance) and a mineral phase. The main constituents of bone mineral are calcium phosphate and calcium carbonate. The mineral components consist mainly of hydroxyapatite crystals and amorphous calcium phosphate. Bone acts ...

Switchable nanoporous films, which can repeatedly alternate their porosities, are of great interest in a diversity of fields. Currently these intelligent materials are mostly based on polyelectrolytes and their porosities can change only in relatively narrow ranges, typically under wet conditions, severely limiting their applications. Here we develop a new system, which is capable of reversibly...

Introduction: Densities and porosities of meteorites provide information about the physical properties of their parent bodies (asteroids). Recent studies report the densities and porosities of ~40 ordinary chondrite (OC) meteorites [1,2]. In this study, we present 42 additional measurements of OC densities and porosities, and provide a rigorous analysis of the errors in the method. Additionally...

Porosities of set and burnout compacts of phosphate-bonded investments were determined. A gas pycnometer was used to measure the volumes, and hence the densities, of fine powders and porous compacts. Porosities of set and burnout compacts were then obtained from these data for as-received powders and dry set compacts by a numerical simulation method, subsequently leading on to the estimated com...

We have prepared three distinct polyamino acid-based metal-organic frameworks (MOFs) with different chiralities and porosities using the same chemistry, by simply modifying the enantiomeric ratio of the chiral organic ligand used.

We model the formation of lunar complex craters and investigate the effect of preimpact porosity on their gravity signatures. We find that while preimpact target porosities less than ~7% produce negative residual Bouguer anomalies (BAs), porosities greater than ~7% produce positive anomalies whose magnitude is greater for impacted surfaces with higher initial porosity. Negative anomalies result...

Abstract Compacts of microcrystalline cellulose were prepared at applied compression pressures 21, 32, 43, 53, and 64 MPa. subjected to elevated temperatures 125°C, 150°C, 175°C according a 5-min heating program. The effect these thermal treatments on compact volumes, densities, porosities, tensile strengths, weight loss was determined. There no change in the volumes compacts due most condition...

The objectives of this study were to analyse the effect of inkjet 3-D printing parameters, particularly the splat overlap distance, for the fabrication of defect-free porous Al2O3 ceramic multilayers, and to correlate the resulting porosities with the mechanical properties measured using nanoindentation. An aqua-based alumina ink was used in this study to fabricate the multilayers on dense alum...

We study acoustic emission avalanches during the process of failure of porous alumina samples (Al2O3) under compression. Specimens with different porosities ranging from 30% to 59% have been synthesized from a mixture of fine-grained alumina and graphite. The compressive strength as well as the characteristics of the acoustic activity have been determined. The statistical analysis of the record...