Wood Dimensional Changes due to Hygrothermal Behaviour

2015 ◽  
Vol 365 ◽  
pp. 172-177
Author(s):  
V.P. de Freitas ◽  
João M.P.Q. Delgado ◽  
N. Machado
Keyword(s):  
Relative Humidity ◽  
Linear Thermal Expansion ◽  
Strong Variation ◽  
Dimensional Changes ◽  
Radial Shrinkage ◽  
Dimension Stability ◽  
Definition Of ◽  
Hygrothermal Behaviour ◽  
Shrinkage Coefficient

Wood has a strong hygroscopic behaviour, with a strong variation of moisture content and dimension stability caused by modifications of the relative humidity of the surrounding air. The properties that define the behaviour of wood facing temperature and moisture actions were studied in this work. Linear thermal expansion, hygroscopicity, shrinkage (tangential and radial shrinkage coefficient) and hygric expansion were given special attention.An experimental device was designed for testing wood samples, red oak. A series of tests was performed including the determination of hygric expansion coefficient and the definition of the sorption curve. This research made possible the evaluation of dimensional stability of wood in transient conditions of relative humidity.

Construction board resistance to accelerated aging

BioResources ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 2680-2690
Author(s):  
Radosław Mirski ◽  
Adam Derkowski ◽  
Dorota Dziurka
Keyword(s):  
Mechanical Properties ◽  
Relative Humidity ◽  
Construction Industry ◽  
Accelerated Aging ◽  
Physical And Mechanical Properties ◽  
Cyclic Test ◽  
Test Cycle ◽  
Dimensional Changes

Physical and mechanical properties were evaluated for industrial and laboratory boards intended to be used in the construction industry. The boards were subjected to accelerated aging tests including resistance to humidity in the conditions of cyclic test in accordance with EN 321 (2002), and determination of dimensional changes resulting from changes in relative humidity according to EN 318 (2002). The greatest changes were observed after one test cycle. Moreover, the boards made of fine chips demonstrated slightly higher resistance to the tested factors. Although laboratory boards showed a much lower density, their behavior following the exposure to the assessed factors was similar to that of industrial plates.

State Failure and the Political Violence Phenomenon: A Comparative Analysis of Iraq and Syria Cases

2016 ◽  
Vol 4 (2) ◽  
pp. 170 ◽  
Author(s):  
K. Eylem Özkaya Lassalle
Keyword(s):  
Cold War ◽  
Political Violence ◽  
State Failure ◽  
The Political ◽  
Collective Violence ◽  
Short Run ◽  
Definition Of ◽  
The Cold War

The concept of failed state came to the fore with the end of the Cold War, the collapse of the USSR and the disintegration of Yugoslavia. Political violence is central in these discussions on the definition of the concept or the determination of its dimensions (indicators). Specifically, the level of political violence, the type of political violence and intensity of political violence has been broached in the literature. An effective classification of political violence can lead us to a better understanding of state failure phenomenon. By using Tilly’s classification of collective violence which is based on extent of coordination among violent actors and salience of short-run damage, the role played by political violence in state failure can be understood clearly. In order to do this, two recent cases, Iraq and Syria will be examined.

DEFINITION OF TIME SPENT ON REPAIR OF BUS TRANSMISSION UNITS TAKING INTO ACCOUNT TECHNOLOGICAL EQUIPMENT RELIABILITY

2020 ◽  
Vol 2020 (9) ◽  
pp. 29-33
Author(s):  
Sergey Bulatov
Keyword(s):  
Negative Impact ◽  
Probabilistic Method ◽  
Technological Equipment ◽  
Quality And Safety ◽  
Transmission Unit ◽  
Equipment Reliability ◽  
Hours Of Work ◽  
Definition Of ◽  
Time Decrease

The paper purpose is the effectiveness estimation in the technological equipment use, taking into account its reliability and productivity for defective transmission units of buses. The problem consists in the determination of time to be spent on repair of bus transmission units taking into account technological equipment reliability. In the paper there is used a probabilistic method for the prediction bus transmission units, and also a method of the dynamics of averages which allow ensuring minimum of costs for units downtime during repair and equipment cost. The need for repair of transmission units (gear box) arises on an average after 650 hours, the average productivity of the bench makes 4.2 bus / hour. The bench fails on the average after 4600 hours of work, the average time of the bench makes 2 hours. In such a way the solution of the problem specified allows analyzing the necessity of time decrease for transmission unit repair to avoid long downtimes of buses in repair areas without negative impact upon high repair quality and safety during the further operation.

Sign in / Sign up

Export Citation Format

Share Document