scholarly journals Effect of Temperature and Pressure of Supercritical CO2 on Dewatering, Shrinkage and Stresses of Eucalyptus Wood

2021 ◽  
Vol 11 (18) ◽  
pp. 8730
Author(s):  
Lin Yang

Supercritical CO2 (SuCO2) dewatering can mitigate capillary tension and reduce wood collapse. In this study, Eucalyptus urophylla × E. grandis specimens were dewatered by SuCO2 at temperatures of 35, 40 and 55 °C, in pressures of 10 and 30 MPa, respectively, for 1h. Effects of temperature and pressure on dewatering rate, moisture content (MC) distribution and gradient, shrinkage and residual stress of wood after dewatering were investigated. The results indicate that the SuCO2 dewatering rate is much faster than that of conventional kiln drying (CKD). The dewatering rate increases with increasing of temperature and pressure; however, pressure has a significant influence, especially for the high-temperature dewatering process; the MC distribution after 1 h dewatering is uneven and MC gradients decrease with reducing of mean final MC of wood. MC gradients along radial direction are much smaller than that in tangential direction; collapse of wood significantly reduces after dewatering due to SuCO2 decreasing the capillary tension, and residual stress of wood during dewatering is mainly caused by pressure of SuCO2, which decreases with increasing temperature. SuCO2 dewatering has great potential advantages in water-removal of wood prone to collapse or deformation.

1992 ◽  
Vol 276 ◽  
Author(s):  
D-G. Oei ◽  
S. L. McCarthy

ABSTRACTMeasurements of the residual stress in polysilicon films made by Low Pressure Chemical Vapor Deposition (LPCVD) at different deposition pressures and temperatures are reported. The stress behavior of phosphorus (P)-ion implanted/annealed polysilicon films is also reported. Within the temperature range of deposition, 580 °C to 650 °C, the stress vs deposition temperature plot exhibits a transition region in which the stress of the film changes from highly compressive to highly tensile and back to highly compressive as the deposition temperature increases. This behavior was observed in films that were made by the LPCVD process at reduced pressures of 210 and 320 mTORR. At deposition temperatures below 590 °C the deposit is predominantly amorphous, and the film is highly compressive; at temperatures above 610 °C (110) oriented polycrystalline silicon is formed exhibiting high compressive residual stress.


2007 ◽  
Vol 28 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Leonardo Vignoli ◽  
Marco Bologna ◽  
Manuela D'Amen

AbstractAmphibian populations are especially sensitive to aquatic parameters, in particular during embryonic and larval life. Our aim was to test for an effect of temperature (T = 13°C, 20°C and 25°C at constant pH = 7) and pH (pH = 5.5, 7 and 8.5 at constant T= 20°C) on embryos of two species of Triturus, T. carnifex carnifex and T. italicus (Amphibia, Salamandridae) using GLM procedure. Trend of embryogenesis processes, time to hatching and rate of development have a similar effect in both species in the used range of temperature and pH. Time to hatching decreased significantly with the increasing temperature. The pH experimental conditions had no effect on T. carnifex embryos survival, while the acidic pH condition raised the mortality rate in T. italicus, whose embryos should be more vulnerable than those of T. carnifex to acidification in nature.


2019 ◽  
Vol 143 ◽  
pp. 313-320 ◽  
Author(s):  
Paula Cassiana Frohlich ◽  
Kátia Andressa Santos ◽  
Fernando Palú ◽  
Lúcio Cardozo-Filho ◽  
Camila da Silva ◽  
...  

2014 ◽  
Vol 886 ◽  
pp. 24-27
Author(s):  
Rong Hua Zhang ◽  
Biao Wu

In this study, nitrogen content greater than 0.9% of 18Cr18MnN austenitic stainless steel were prepared by high pressure reaction kettle. The relationships between nitrogen content and temperature, pressure were studied. The results show the nitrogen content in steel increases with increasing melting pressure, at air pressure 1.0MPa<P<1.4MPa, the increase of nitrogen content in steel is evident particularly. In the 1813k<T<1913k temperature range, the nitrogen content in steel decreases with the increasing temperature, there are differences in variation in the temperature range. When temperature is up to 1813K, nitrogen content can be as high as 1.075%. The best thermodynamic condition of melting a nitrogen content of 0.9% 18Mn18Cr austenitic stainless steel is: pressure and temperature are 1.32MPa, 1873k, respectively.


2010 ◽  
Vol 129-131 ◽  
pp. 230-234
Author(s):  
Ying Ying Zhang ◽  
Qi Lin Zhang ◽  
Chuan Zhi Zhou ◽  
Ying Zhou

As composite, the mechanical properties of coated fabrics are sensitive to environment. This paper presented mechanical properties under different environments. A list of uniaxial tests are carried out under different temperatures including -20°C, 0°C, 23°C, 50°C, and 70°C. First, the tensile behaviors at room temperature and the failure behaviors are studied. Then, the effects of temperature on mechanical properties are determined. Finally, the effects of water immersion on mechanical properties are discussed. Results show PTFE coated fabrics remained unchanged in varying temperature and humidity. The temperature has effects on the mechanical properties of PVC coated fabrics. With increasing temperature, the strength decrease and the strain at break increase. The temperature induction factors are proposed for the design and analysis. The water immersion has little effect on the mechanical properties because of the impervious coating.


Parasitology ◽  
1991 ◽  
Vol 102 (3) ◽  
pp. 391-395 ◽  
Author(s):  
D. Meyrowitsch ◽  
N. Ø. Christensen ◽  
O. Hindsbo

The effect of temperature (19–36 °C) and snail host density (0.014–10 snails/1) on the snail-finding capacity of Echinostoma caproni cercariae is described. The initial swimming speed increased whereas the length of the infective period decreased with increasing temperature. The combined effect resulted in the E. caproni cercarial snail-finding capacity being temperature independent in the range 19 to 36 °C at a snail density of 0·014 snails/1. A moderate temperature dependency was, however, seen at a lower snail density. The cercarial snail-finding capacity was snail-host density dependent in the density range 0.014 to 1 snail/1. The findings from this study show that a relatively low and biologically realistic snail host density must be used in experimental studies if realistic estimates of the dynamics of cercarial transmission are to be obtained.


2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
A. Mallik ◽  
B. C. Ray

This review discusses briefly the important aspects of thin films. The introduction of the article is a summary of evolution of thin films from surface engineering, their deposition methods, and important issues. The fundamental aspects of electrochemical deposition with special emphasis on the effect of temperature on the phase formation have been reviewed briefly. The field of sonoelectrochemistry has been discussed in the paper. The literature regarding the effects of temperature and sonication on the structure and morphology of the deposits and nucleation mechanisms, residual stress, and mechanical properties has also been covered briefly.


The question as to whether the thermal conductivity of a solid varies with temperature is an important one, and a considerable amount of attention has been bestowed on it. The experimental work which has been done cannot, however, be said to have led to a definite conclusion, owing to the discrepancies between the results obtained by different observers. Although the more recent of these results have produced a general disbelief of the idea which prevailed a few years ago, that the thermal conductivity of a solid would increase as the temperature increased, yet they do not justify the opposite conclusion being drawn.


Sign in / Sign up

Export Citation Format

Share Document