Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Durability


Long Term Strength and Durability of Clayey Soil Stabilized With Lime

Abdulrahman H. Al-Zubaydi; Moafaq A. Al-Atalla; Ibrahaim M. Al-Kiki

Engineering and Technology Journal, 2011, Volume 29, Issue 4, Pages 725-735

This study deals with durability characteristics and unconfined compressive
strength of clayey soil stabilized with lime. The tests comprises of unconfined
compressive strength for samples stabilized with the optimum lime percent (4%),
and subjected to cycles of the wet-dry, dry-wet and freeze-thaw durability tests as
well as, long-term soaking and slake tests.
The results indicated that, the efficiency of the lime in the improvement of
unconfined compressive strength of clayey soil is of negative effect in the long
term durability periods The wetting-drying cycles showed greater reduction in
unconfined compressive strength than drying-wetting cycles, while the volume
change of samples which subjected to drying at first, was greater than those
conducted with wetting. On the other hand, freezing-thawing cycles causes a
decreasing in the unconfined compressive strength values, and the reduction ratio
was greater than wetting and drying cases. But, during soaking tests it was found
that at early soaking periods, the lime stabilized samples continuously gaining
strength, but beyond this the strength decreased with increasing soaking period.
Finally, the stabilized samples with (4 and 6%) lime becomes more durable
against the cycles of wetting and drying.

The Effects of Different Environmental Conditions on the Characteristics of Fiber Reinforced Plates

Ghydaa K. Yass; Safaa H. Abdul Rahman

Engineering and Technology Journal, 2010, Volume 28, Issue 11, Pages 2259-2275

The failure of polymer matrix composite upon exposure to the environment
conditions has been assessed in the present study. Glass fabrics and unsaturated
polyester resin were selected to fabricate 8-layer laminates cross ply [(0/90)8]
arranged in symmetric and antisymmetric stacking sequence. Environmental
conditioning using Sea and Tap water with humidity exposure and Ultraviolet
radiation was conducted to investigate the vibrations characteristics of symmetric
and antisymmetric composite samples. After exposure time to the conditions
above for 500, 1000 and 2000 hr, laminates were subjected to three point bending
testing, in order to study their flexural properties (stiffness and strength) before
and after these exposures. Then a finite element analysis using the package
program ANSYS (version 10) was used for the analysis of free vibration
characteristics. The object was to obtain the natural frequency for each case of
environmental conditions at different exposure times. The results showed that
natural frequencies of cantilever laminate plates decreased with the increased
exposure time for the different environmental conditions.

Fusion Face and Palmprint for Human Recognition via Spectral Eigenvector

Hana; a M. Salman

Engineering and Technology Journal, 2009, Volume 27, Issue 4, Pages 787-798

The Biometrics recognition systems act as an efficient method with broad
applications in the area of: security access control, personal identification to humancomputer
communication. From other hand, some biometrics have only little variation
over the population, have large intra-variability over time, or/and are not present in all
the population. To fill these gaps, a use of multimodal biometrics is a first choice
solution [1].
This paper describes a multibiometrics method for human recognition based on
new teacher vector identified as spectrum eigenface, and spectrum eigenpalm. The
proposed combination scheme exploits parallel mode capabilities of the fusion feature
vectors in matching level and invokes certain normalization techniques that increase its
robustness to variations in geometry and illumination for face and palmprint. The
correlation distance is used as a similarity measure. A threshold value is used to
prevent the imposter for being recognized. Experimental results demonstrate the
effectiveness of the new method compared to the unimodal biometrics for spectrum
eigenface/eigenpalm.

Modeling Time to Corrosion Initiation in High-Performance Ferrocement Exposed to Chlorides Environments

J. Forth; Maan S. Hassan; S. A. Salih

Engineering and Technology Journal, 2009, Volume 27, Issue 1, Pages 18-31

The applications of a mineral admixture, or a zinc coating to steel surface, or a
combination of both are methods used for the corrosion prevention of ferrocement
element in this study. Results of a study to evaluate many corrosion protection systems
with metakaolin and/or galvanized steel mesh are presented in six U-shaped specimens.
Specimens were built to simulate exposure conditions typical for marine environment.
Laboratory data collected along duration of 40 weeks of exposure were used in
modeling the cover depth as a function of time to corrosion initiation of the investigated
corrosion prevention methods. Methods used to assess the condition of specimens
included chloride concentration measurements, and corrosion rates. Model predictions
show that the ferrocement specimen of high-performance mortar with metakaolin
provides much better level of protection against moisture and chlorides than the
conventional specimen, by delay rate of chloride ingress. Application of a galvanized
steel mesh causes an elevation of the chloride threshold resulting in an additional
increase in the predicted time to corrosion initiation.