An experiment was conducted on maize crop (Zea mays L.) in plastic pots in two
different soils (Qurna soil, which is poor organic matter and the other soil from
Maysan marshes, which is rich in organic matter), to study the effect of selenium,
sul
fur and phosphate and their interaction on dry weight of shoot of maize crop.
Selenium was added at four levels (0, 10, 20 and 40 g Se ha), sulfur at three
levels (0, 30 and 60 kg S ha), and phosphorus at three levels (0, 60 and 120 kg P
ha).
desulfurization study of gas oil is very important, in
order to reduce the resulted pollution from acidic gas SO2, which
results by burning the fuel, and to prevent poisoning of sensitive
catalysts with sulfur, in subsequent processes, and to prev
ent
corrosion of engines and equipment in refineries. So, refineries
have been restricted by very low sulfur content, in their products.
Because the hydrodesulphurization did not demonstrate good
efficiency in reducing the sulfur and aromatics content to the
required limits, it has been to search for alternative or completed
methods for it .One of these processes is the oxidation –extraction
method, which has been studied in our work. We used hydrogen
peroxide as oxidant, and acetonitrile as extraction solvent. We
studied Operation conditions in terms the proportion of oxidant and
extraction solvent to fuel, and we chose the operation temperatures
to suit the specifications of the oxidant and extraction solvent. We
studied diesel specifications, which we applied at it the process of
oxidation and extraction.
In this paper we present the preparation of PbS nanocrystalline thin films
using Chemical Bath Deposition (CBD) technique. We have performed this
work in order to study the photoconductivity of PbS semi-conductor thin films.
The details of the pre
paration method are described. Thickness of deposited
films has been determined using mechanical and optical methods. From the
optical absorption measurements we have determined the band gap values.
Using the first approximation parabolic bands model and the obtained values
of band gaps, we have determined the size of PbS nanocrystallites. Also, we
have investigated the electrical and photoelectrical behaviors of the PbS films.
Our study shows that the size of PbS thin films nanocrystallites affects the
photoconductive properties of the material. Furthermore, investigations show
that there are two different sizes of grains located in two different layers, the
first one, with grain’s size of about 25nm, concerns the part of PbS deposited
directly on the glass substrate and the second layer, with grain’s size of about
70nm, concerns the PbS deposited on the first layer.
