STUDY OF THE TRANSIENT HYGROTHERMAL BEHAVIOUR OF A MULTI-LAYERED HEMP CONCRETE WALL

2009 ◽  
Author(s):  
Anh Dung Tran Le ◽  
Chadi Maalouf ◽  
Ton Hoang Mai
Keyword(s):  
Concrete Wall ◽  
Hygrothermal Behaviour

Comportement thermohydrique d’une paroi en béton : influence du type de béton, influence du type de chargement

2007 ◽  
Vol 34 (10) ◽  
pp. 1364-1370
Author(s):  
M Shekarchi ◽  
G Debicki
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Phase Transfer ◽  
Moisture Distribution ◽  
Transfer Model ◽  
Concrete Wall ◽  
Two Phase ◽  
Ordinary Concrete ◽  
Hygrothermal Behavior ◽  
Hygrothermal Behaviour

Tests simulating “the accidental conditions” and the “test of heating,” without the contribution of humidity, have been carried out on test equipment that we designed and fabricated in the scope of this work. The tests have been carried out on laterally sealed and insulated cylindrical specimens of ordinary or high-performance concrete having a thickness of 1.3 m. Experimental results present temperature, pressure, and moisture distribution throughout the specimens and permit to characterize the hygrothermal behaviour of a concrete wall. The different aspects of the phenomena affecting a two-phase transfer (steam, water) in a porous medium are presented. Test results show that high-performance concrete exposed to an increase in temperature presents a particular hygrothermal behaviour, because of its microstructure, that is put into evidence, notably while looking at the role of the silica fume. The migration of water is not as rapid in high-performance concrete as in ordinary concrete, which is favourable for tightness. Numerical investigation consists of adapting a heat and mass transfer model, initially built for ordinary concrete, to the high-performance concrete used in this work.Key words: hygrothermal behavior, concrete wall, ordinary concrete, high-performance concrete, leak tightness, temperature distribution, pressure distribution, moisture distribution.

scholarly journals University of Kiel Radiocarbon Measurements II

Radiocarbon ◽  
1967 ◽  
Vol 9 ◽  
pp. 257-260
Author(s):  
H. Willkomm ◽  
H. Erlenkeuser
Keyword(s):  
Proportional Counter ◽  
Atmospheric Pressure ◽  
Statistical Error ◽  
Quartz Tube ◽  
Sensitive Volume ◽  
Concrete Wall ◽  
Lead Shield ◽  
Double Ring

Most of the measurements reported here have been obtained with the 4.5-L CO2 counter previously described (Kiel I; Erlenkeuser, 1965). A few samples have been dated with a 3-L proportional counter. The copper counter is surrounded by 28 GM counters in the form of a double ring. The total assembly is shielded by 10 cm of old lead. Neither an inner lead shield between counter and anticoincidence ring nor screening of sensitive volume by a quartz tube-as in the 4.5-L counter-has been used. Background of the small counter is 17.20 cpm or The 0.95 x NBS value is 9.5 cpm at 400 torr. Within statistical error background does not depend on atmospheric pressure. The 3-L counter is placed under a concrete wall, 2.5 m in length and 9.4 m in height.

scholarly journals Optically transparent and very thin structure against electromagnetic pulse (EMP) using metal mesh and saltwater for shielding windows

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Duy Tung Phan ◽  
Chang Won Jung
Keyword(s):  
Electromagnetic Pulse ◽  
Low Cost ◽  
High Energy ◽  
Metal Plate ◽  
Optical Transparency ◽  
Shielding Effectiveness ◽  
Concrete Wall ◽  
Metal Mesh ◽  
Wide Range ◽  
Optically Transparent

AbstractAn electromagnetic pulse (EMP) with high energy can damage electronic equipment instantly within a wide range of thousands of kilometers. Generally, a metal plate placed inside a thick concrete wall is used against an EMP, but it is not suitable for an EMP shielding window, which requires not only strong shielding effectiveness (SE) but also optical transparency (OT). In this paper, we propose a very thin and optically transparent structure with excellent SE for EMP shielding window application. The proposed structure consists of a saltwater layer held between two glass substrates and two metal mesh layers on the outside of the glass, with a total thickness of less than 1.5 cm. The SE and OT of the structure are above 80 dB and 45%, respectively, which not only meet the requirement of EMP shielding for military purposes but also retain the procedure of good observation. Moreover, the OT of the structure can be significantly improved using only one metal mesh film (MMF) layer, while the SE is still maintained high to satisfy the required SE for home applicants. With the major advantages of low cost, optical transparency, strong SE, and flexible performance, the proposed structure can be considered a good solution for transparent EMP shielding windows.

scholarly journals Displacement-Based Seismic Assessment of the Likelihood of Failure of Reinforced Concrete Wall Buildings

Buildings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 295
Author(s):  
Amirhossein Orumiyehei ◽  
Timothy J. Sullivan
Keyword(s):  
Reinforced Concrete ◽  
Seismic Risk ◽  
Concrete Wall ◽  
Limit States ◽  
Simplified Approach ◽  
Performance Based Assessment ◽  
Assessment Approach ◽  
Reinforced Concrete Wall ◽  
Displacement Based ◽  
Assessment Procedures

To strengthen the resilience of our built environment, a good understanding of seismic risk is required. Probabilistic performance-based assessment is able to rigorously compute seismic risk and the advent of numerical computer-based analyses has helped with this. However, it is still a challenging process and as such, this study presents a simplified probabilistic displacement-based assessment approach for reinforced concrete wall buildings. The proposed approach is trialed by applying the methodology to 4-, 8-, and 12-story case study buildings, and results are compared with those obtained via multi-stripe analyses, with allowance for uncertainty in demand and capacity, including some allowance for modeling uncertainty. The results indicate that the proposed approach enables practitioners to practically estimate the median intensity associated with exceeding a given mechanism and the annual probability of exceeding assessment limit states. Further research to extend the simplified approach to other structural systems is recommended. Moreover, the research highlights the need for more information on the uncertainty in our strength and deformation estimates, to improve the accuracy of risk assessment procedures.

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