CaMnO3 was synthesized by a Solid State method. MnO2 and
CaO were used as precursors. The temperature of synthesis was
1100°C. X-ray diffraction analysis (XRD) revealed that the
CaMnO3 was synthesized. XRD results showed that the prepared
compound was polycrystalline and had orothohombic structure.
Due to the importance of Strontium Titanate in modern
technological industries, optical devices, solar cells and other
utilization; in this research we study the synthesis of ST from
SrCO3:TiO2 (1:1).
The research focused on the conclusion of a mathematical model to determine the
proportion of nitrogen oxides emitted from the internal combustion engine based on the
equations of chemical interaction of direct and reverse the conventional fuel wit
h the use of
many of the correction coefficients, as well as the possibility of developing this model.
Search to find out the concentration of nitrogen oxides NO changes resulting from the
combustion of fuel in internal combustion engines that run on diesel fuel and gasoline
adopted, during work time, and then transform this relationship to calculate the ratio of the
concentrations according to the angle of rotation of the engine crankshaft.
In this paper an experimental investigation of unsaturated polyester(UPR) with
different weight fractions(2,4,5,7 )wt% of (Al2O3,MgO,TiO2) as powders ,has been done.
the identification of their flammability and fire resistance ranges are found out
. the time
needed to puncture the samples, the mass loss, the diameter variation ,and the flame effect
on the samples surface are measured. the samples were tested by Oxyacetylene flame using
a device which is designed in the Faculty of Mechanical and Electrical Engineering labs.
The results showed that (MgO) is the best one for its flammability and fire
resistance. The longest time before puncture , and the lowest mass loss were achieved by(
UPR+ 7% MgO) with(16% mass loss in 112 sec ), while pure UPR has ( 27% mass loss in
45 sec).
In this paper an experimental investigation of unsaturated polyester(UPR) with
different weight fractions(2,4,5,7 )wt% of (Al2O3,MgO,TiO2) as powders ,has been done.
the identification of their flammability and fire resistance ranges are found out
. the time
needed to puncture the samples, the mass loss, the diameter variation ,and the flame effect
on the samples surface are measured. the samples were tested by Oxyacetylene flame using
a device which is designed in the Faculty of Mechanical and Electrical Engineering labs.
The results showed that (MgO) is the best one for its flammability and fire
resistance. The longest time before puncture , and the lowest mass loss were achieved by(
UPR+ 7% MgO) with(16% mass loss in 112 sec ), while pure UPR has ( 27% mass loss in
45 sec).
Resonant photoemission of single crystals of the perovskite TbBaCoO3 has been carried out for freshly scraped surfaces. The resonance onset energy at the Co3p→3d threshold is used to explore the contribution of Co3d electrons to the electronic struct
ure of the valence band. The Energy Distribution Curves (EDC) corresponding to the valence band of the crystal were determined for radiation energies hv in the region of hv=60 eV. For 63.2 eV binding energy, the main contribution of Co 3d electrons was found in the main valence band peak located at 7.46 eV below the Fermi level, whereas the contribution of Tb4f electrons was found at energy 12.08 eV below the Fermi level. The results show that the density of states close to the Fermi energy is of Co3d/O2p character, with any Tb4f contribution.
There are wide uses of tin oxide thin films, especially in the field of
transparent conductors, solar cells, gas sensors and piezoelectric materials.
Laser deposition is considered one of the most important techniques followed to
obtain these film
s. In this research, we develop a technique to obtain
homogeneous thin films of tin oxide depending on vaporization of pile targets of
this oxide by continuous CO2 laser in the atmosphere, with a fan which
guarantees obtaining homogenous films. Some of these films were annealed in
different conditions. The optical microscope images revealed the presence of
high degree of homogeneity, while the X-Ray study showed different
crystallization grain orientations which depend on the preparation conditions.
The preferred direction is (110). The optical absorption gives information
about the value of the effective band gal for the samples before and after
thermal annealing. We have found that some films have Eg = 3.2 ev. before
annealing, and after long annealing they have Eg=1.3ev. In addition, the hard
annealed thin films reveal anisotropy in the optical and electrical.
Characteristics, they have different absorption coefficients in two
perpendicular directions, also there is an electrical resistance anisotropy along
these two directions especially after hard annealing. The Eb was 0.73 ev before
annealing, it became 0.37 ev for one direction and 0.32 ev for the other
direction.
