this research has been conducted to investigate the influence of steam temperature and densification percentage on withdrawal strength of nail and screw joints as well as flexural strength in compressed wood of eastern cottonwood (populus deltoeides). for this purpose 15 healthy standing trees of eastern cottonwood were selected from dr. bahramnia forest located in shasht-kola (gorgan). the fla...

-The densification of a porous intermetallic alloy (Ti-14wt%AI-21wt%Nb) during the final stage of densification has been investigated under various states of stress and compared with the predictions of current models for densification by power-law creep. The experiments generally confirm the model predictions that the densification rate is a sensitive function of the stress state. Experimentall...

The densification of zinc powders by uniaxial hot pressing is investigated under both isothermal and thermal cycling conditions. Thermal cycling results in enhanced densification kinetics as compared to isothermal compaction at the upper cycle temperature. Using mechanistic models of initial-stage powder densification, the experimental data are analyzed to reveal the creep stress-exponent and a...

The kinetics of hot-pressing for undoped and donor-doped BaTiO3 of high purity have been studied at 1050~ and at 2.3 to 27.6 MPa in an oxidizing atmosphere. The stress exponent and grain size exponent of the densification rate are indicative of control of densification by a grain boundary diffusion mechanism. The activation enthalpy (,~ 400 kJ mo1-1 ) for the densification process has been meas...

Densification in highly porous, isothermal firn occurs primarily by Newtonian sliding on grain boundaries, but the coordination number increases with density and restricts further sliding. At a relative density of about 0.6 the coordination number approaches 6 and sliding ceases to be a primary mechanism of densification; the resulting decrease in densification rate causes the critical point in...

Sintering of nanoparticle inks over large area-substrates is a key enabler for scalable fabrication of patterned and continuous films, with multiple emerging applications. The high speed and ambient condition operation of photonic sintering has elicited significant interest for this purpose. In this work, we experimentally characterize the temperature evolution and densification in photonic sin...

This paper focuses on modeling ride requests and their variations over location and time, based on analyzing extensive real-world data from a ride-sharing service. We introduce a graph model that captures the spatial and temporal variability of ride requests and the potentials for ride pooling. We discover these ride request graphs exhibit a well known property called “densification power law” ...

During sintering a powder compact gains strength through low-temperature interparticle bonding, usually induced by solid-state surface diffusion, followed by further strength contributions from high-temperature densification. In cases where a liquid phase forms, sintering densification is accelerated and shape retention is sustained while open pores remain and contribute capillary forces. Unfor...

Multiphase (MP) monoclinic and cubic Y2O3 nanoparticles, 40 nm in diameter, were densified by spark plasma sintering for 5–15 min and100 MPa at 1000 C, 1100 C, and 1500 C. Densification started with pressure increase at room temperature. Densification stagnated during heating compared to the high shrinkage rate in cubic single-phase reference nanopowder. The limited densification of the MP nano...

Prealloyed powders usually melt over a range of temperatures. This feature is useful in performing supersolidus liquid phase sintering, where liquid forms inside the particles when heated just over the solidus temperature. Densification by supersolidus liquid phase sintering is sensitive to time-temperatures. A major difficulty arises when a narrow temperature range exists between densification...