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Effect of the Anodization Parameters on the Volume Expansion of Anodized Aluminum Films

Research Abstract

The effect of anodization parameters, e.g. anodizing voltage, anodizing current, duration time, electrolyte temperature, electrolyte type and concentration, on the volume expansion of anodized Al, Al-1wt%Si and Al-1%Cu thin films have been studied. The volume expansion factor of anodic porous alumina is found to vary from 1.32 to 2.08, depending on the anodizing voltage, anodizing current density and electrolyte type. The electrolyte temperature and impurity type have slight effect on the volume expansion factor. The relation between the pore density of porous alumina and the anodizing voltage is found to follow the relation NP=9.4×1010exp(-0.042V). In addition, the current efficiency during the anodization was determined to be about 83%.

Research Authors
Alaa M. Abd-Elnaiem, A.M. Mebed, A. Gaber, M.A. Abdel-Rahim
Research Department
Research Journal
International Journal of Electrochemical Science
Research Member
Research Pages
PP.10515 - 10525
Research Rank
1
Research Vol
8
Research Website
http://www.electrochemsci.org/papers/vol8/80810515.pdf
Research Year
2013

Crystallization study of Sn additive Se–Te chalcogenide alloys

Research Abstract

Results of differential thermal analysis (DTA) under non-isothermal conditions of glasses Se90

xTe10Snx
(x = 0, 2.5, 5 and 7 at.%) are reported and discussed. The glass transition temperature (Tg), the onset crystallization
temperature (Tc) and the peak temperature of crystallization (Tp) were found to be dependent
on the compositions and the heating rate. Values of various kinetic parameters such as activation energy
of glass transition (Eg), activation energy of crystallization (Ec), rate constant (Kp), Hurby number (Hr)
and the order parameter (n) were determined. For the present systems, the results indicate that the rate
of crystallization is related to thermal stability and glass forming ability (GFA). According to the Avrami
exponent (n), the results show a one dimensional growth for the composition Se90Te10 and a three dimensional
growth for the three other compositions. The crystalline phases resulting from DTA and (SEM) have
been identified using X-ray diffraction.

Research Authors
M.A. Abdel-Rahim, A. Gaber, A.A. Abu-Sehly, N.M. Abdelazim
Research Department
Research Journal
Thermochimica Acta
Research Pages
PP.274– 280
Research Rank
1
Research Vol
Vol.566
Research Year
2013

Crystallization study of Sn additive Se–Te chalcogenide alloys

Research Abstract

Results of differential thermal analysis (DTA) under non-isothermal conditions of glasses Se90

xTe10Snx
(x = 0, 2.5, 5 and 7 at.%) are reported and discussed. The glass transition temperature (Tg), the onset crystallization
temperature (Tc) and the peak temperature of crystallization (Tp) were found to be dependent
on the compositions and the heating rate. Values of various kinetic parameters such as activation energy
of glass transition (Eg), activation energy of crystallization (Ec), rate constant (Kp), Hurby number (Hr)
and the order parameter (n) were determined. For the present systems, the results indicate that the rate
of crystallization is related to thermal stability and glass forming ability (GFA). According to the Avrami
exponent (n), the results show a one dimensional growth for the composition Se90Te10 and a three dimensional
growth for the three other compositions. The crystalline phases resulting from DTA and (SEM) have
been identified using X-ray diffraction.

Research Authors
M.A. Abdel-Rahim, A. Gaber, A.A. Abu-Sehly, N.M. Abdelazim
Research Department
Research Journal
Thermochimica Acta
Research Member
Abdel-fatah Jaber Mohamoud Abd Allah Elbos
Research Pages
PP.274– 280
Research Rank
1
Research Vol
Vol.566
Research Year
2013

Incorporating the concept of equivalent freshwater head in successive horizontal simulations of seawater intrusion in the Nile Delta aquifer, Egypt

Research Abstract

A new approach to study seawater intrusion problems in coastal aquifers is presented. The approach is
demonstrated for the case of the Nile Delta aquifer in Egypt. FEFLOW, a 3D finite element variable density
model, is employed, however, because of the lack of 3D data, and to demonstrate the proposed approach,
the simulations are performed in 2D horizontal views. The concept of equivalent freshwater head (usually
implemented in 2D vertical simulations) is adapted in the horizontal (areal) simulations. After calibration
against field observations, the simulations are conducted at four horizontal sections located at
different levels (100, 200, 300 and 400 m) below the mean seawater level. The depth of the horizontal
section is identified through assigning an appropriate pressure ‘‘equivalent freshwater’’ head at the
boundaries. The study domain is modified for the horizontal sections at 300 and 400 m, respectively,
to account for the aquifer geometry at these depths. The effect of freshwater recharge from the Nile River
on the seawater intrusion is observed in the upper layer around its two main branches. The results of the
horizontal simulations clearly demonstrate the variation of water concentration in the vertical direction.
As the depth increases, the transition zone (in which the concentration varies from the seawater to the
freshwater concentration) is shifted toward the landside and become more extensive. At the lower levels
of the Nile Delta aquifer, the seawater migrates much further inland as compared to the shallower levels.
The concept of horizontal simulations at different levels is further developed to produce meaningful concentration
distributions in the vertical sections. This approach allows for a better realization of seawater
intrusion in coastal aquifers.

Research Authors
Mohsen Sherif, Ahmed Sefelnasr, Akbar Javadi
Research Department
Research Journal
Journal of Hydrology
Research Pages
168-198
Research Publisher
Elsevier
Research Rank
1
Research Vol
464-465
Research Website
http://www.sciencedirect.com/science/article/pii/S0022169412005835
Research Year
2012

Impacts of Seawater Rise on Seawater Intrusion in the Nile Delta Aquifer, Egypt

Research Abstract

Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater
intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the
dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater
rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain
geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with
seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater
pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of
the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem
in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the
effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different
scenarios are considered. Scenarios one, two, and three assume a 0.5m seawater rise while the total pumping is reduced by 50%,
maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0m seawater rise and the
total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study
domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will
be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta.
Scenario six represents the worst case under which the volume of freshwater will be reduced to about 513 km3 (billionm3).

Research Authors
Ahmed Sefelnasr and Mohsen Sherif
Research Department
Research Journal
Groundwater
Research Pages
264-276
Research Publisher
Elsevier
Research Rank
1
Research Vol
52-2
Research Website
http://onlinelibrary.wiley.com/doi/10.1111/gwat.12058/abstract
Research Year
2014

Modelling of paleo-saltwater intrusion in the northern part of the Nubian Aquifer System, Northeast Africa

Research Abstract

A numerical groundwater model of the Nubian
Aquifer System was established to prove the influence of
rising seawater levels on the groundwater salinity in
northern Egypt over the last 140,000years. In addition,
the impact of a groundwater recharge scenario for these
140,000years, involving climatic change, on the saltwater/
freshwater interface was investigated. Saltwater intrusion
induced by rising water levels of the Mediterranean Sea
led to salinisation from the Mediterranean Sea to the
Qattara depression. This modeling approach was supported
by a density-driven model setup and calculation.
The modelled saltwater/freshwater interfaces partially
fitted the observed ones, especially in the southern half
of the Qattara depression. In other parts of the northern
Nubian Aquifer System, the ingression of salt water was
modelled adequately, but in the west, small regions of the
measured interface were not. The development in the
Qattara depression (Egypt) and Sirte basin (Libya) were
investigated in more detail. The different behaviour in
the Sirte basin may be due to high evapotranspiration
rates in some former periods, salt solutions from the pre-
Quaternary layers or saltwater infiltration from sabkhalike
recent salt-bearing sediments.

Research Authors
Ahmed Sefelnasr
Research Department
Research Journal
Hydrogeology Journal
Research Rank
2
Research Vol
Vol. 18
Research Year
2010

Anodized Alumina with Tailored Pore Architectures

Research Authors
Alaa M. Abd-Elnaiem, Cedric Huyghebaert, Mohamed A. Gaffar, Philippe M. Vereecken
Research Department
Research Journal
63rd annual International Society of Electrochemistry (ISE) meeting, August 2012, Prague, Czech Republic.
Research Member
Mohamed Abdel-aziz Mohamed Gaafar
Research Rank
3
Research Year
2012
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