Iraqi Journal of Physics

In this study, Gamma-ray spectrometry with (HPGe) detector was used to
measure the specific activity concentrations of 226Ra, 232Th, and 40K in soil samples
collected from IT1 oil reservoirs in Kirkuk city, northeast Iraq. The “spectral line
Gp” gamma analysis software package was used to analyze the spectral data. 226Ra
specific activity varies from 9 ± 0.34 Bq.kg-1 to 17 ± 0.47 Bq.kg-1. 232Th specific
activity varies from 6.2 ± 0.08 Bq.kg-1 to 18 ± 0.2 Bq.kg-1. 40K specific activity
vary from 25 ± 0.19 Bq.kg-1 to 118 ± 0.41 Bq.kg-1. The radiological hazard due to
the radiation emitted from natural radionuclides in soil samples was also assessed.
The average values of the radium equivalent (Raeq), external hazard index (Hex),
internal hazard index (Hin), gamma index (Iγ), absorbed dose rate (D), outdoor
(AEDEout) and indoor (AEDEin) annual effective dose equivalent were 35.391
Bq.kg-1, 0.095, 0.128, 0.253, 16.118 nGy.h-1, 0.0197 mSv.y-1, and 0.0790 mSv.y-1,
respectively. All values obtained for the activity concentrations for 226Ra, 232Th,
and 40K and the radiological hazard were lower than the global values. This
indicates that no harmful radiation effects are posed to the population who work
and live near the study area.

A simple physical technique was used in this study to create stable and
cost-effective copper oxide (CuO) nanoparticles from pure copper metal using the
pulsed laser ablation technique. The synthesis of crystalline CuO nanoparticles
was confirmed by various analytical techniques such as particle concentration
measurement using atomic absorption spectrometry (AAS), field emission
scanning electron microscopy (FE-SEM), the energy dispersive X-ray (EDX), and
X-ray diffraction (XRD) to determine the crystal size and identify of the crystal
structure of the prepared particles. The main characteristic diffraction peaks of the
three samples were consistent. The corresponding 2θ is also consistent, and the
cytotoxicity of the nanoparticles was also investigated. After 24 hours of
exposure, the percentage of cytotoxicity was calculated. The maximum toxicity of
Hep-G2 was 37.81% at the maximum concentration of (500) µg mL-1 after 24
hours of exposure. Also, the maximum toxicity of the normal cell line was
27.85% at a maximum concentration of (500) µg mL-1.

Climate change is one of the global issues that is receiving wide attention
due to its clear impact on all living organisms. This is essential for Iraq since it was
classified as the fifth most vulnerable country to climate change. One of the
manifestations of these changes in Iraq is the increasing frequency and severity of
dust storms. In this study, the Normalized Difference Dust Index (NDDI) spectral
index for Moderate Resolution Imaging Spectroradiometer (MODIS) sensor bands
was used to measure and track the dust storm that occurred on May 16, 2022, as
well as to test the validity of one of the daily products of this sensor, MOD11A1, to
measure surface temperature and emissivity before and after the storm. It was
found that the MOD09GA product is effective in monitoring and detecting dust
storms. The areas close to the Syrian borders were identified as the origin of this
storm. On the other hand, the MOD11A1 product is not suitable for daily
monitoring due to the large number of missing pixels that cannot be compensated
by conventional statistical methods or spatial interpolation techniques, as the
percentage of missing data sometimes equals half or more of the scene, despite the
fact that both products are from the same location and time of capture and under
the same weather conditions. Therefore, it’s not suitable for daily monitoring of
dust storm phenomena. The average of these data for eight days after image
processing can be relied upon to monitor other phenomena or applications.

In this work, an anti-reflection coating was prepared in the region (400-1000)
nm of wavelength, with a double layer of silicon dioxide (SiO2) as an inner layer and
the second layer of the mixture (SiO2) and titanium dioxide (TiO2) with certain
ratios, as an outer layer using the chemical spraying method with a number of 6
sprays of layer SiO2 and 12 sprays of layer SiO2 - TiO2. Using the method of
chemical spraying deposited on the glass as a substrate with a different number of
sprays of SiO2, and a fixed number of TiO2-SiO2. The optical and structural
properties were determined using UV-Vis spectroscopy and atomic force
microscopy (AFM). The results show that by using a mixed layer, the optimal
optical performance of a broadband low-reflection ARC (anti-reflection coating) was
obtained. The work also reports the comparison of experimental and theoretical
results with the help of MATLAB, which relies on the characteristic matrix along
the visible region – near-infrared.

Developing and researching antenna designs is analogous to excavating in
an undiscovered mine. This paper proposes a multi-band antenna with a new
hexagonal ring shape, theoretically designed, developed, and analyzed using a CST
before being manufactured. The antenna has undergone six changes to provide the
best performance. The results of the surface current distribution and the electric
field distribution on the surface of the hexagonal patch were theoretically analyzed
and studied. The sequential approach taken to determine the most effective design
is logical, and prevents deviation from the work direction. After comparing the six
theoretical results, the fifth model proved to be the best for making a prototype.
Measured results represent that the proposed antenna can operate well in three
bands with a return loss of -11.24 dB at 2.9 GHz, -25.99 dB at 4.9 GHz, and -21.26
dB at 5.4 GH. This type of antenna belongs to various wireless communication
systems, including 2G, 3G, 4G, and 5G.

This work presents a five-period chaotic system called the Duffing
system, in which the effect of changing the initial conditions and system
parameters d, g and w, on the behavior of the chaotic system, is studied. This work
provides a complete analysis of system properties such as time series, attractors,
and Fast Fourier Transformation Spectrum (FFT). The system shows periodic
behavior when the initial conditions xi and yi equal 0.8 and 0, respectively, then
the system becomes quasi-chaotic when the initial conditions xi and yi equal 0 and
0, and when the system parameters d, g and w equal 0.02, 8 and 0.09. Finally, the
system exhibits hyperchaotic behavior at the first two conditions, 0 and 0, and the
bandwidth of the chaotic signal becomes wider (2 a.u.) than in the first case. So,
this system can be used in many physical applications, such as encrypting
confidential information.

This study investigates the changes occurring in the province of Basra
using geospatial methods and analyzes the variations in land surface temperature
among the various types of land cover. For the months of July and December in the
years 2013 and 2021, Landsat images were used in Landsat 8 OLI/TIRS, and
satellite images were processed using ArcGIS 10.8 software. The study's categories
for land use and land cover were generated through the application of supervised
classification techniques, and the land surface temperature was calculated using
data from a satellite sensor's brightness temperature. According to the study's
findings, there has been an increase in urban area, (including barren land). From
2013 to 2021, a greater correlation between urban land and LST was found,
indicating an increasing surface urban heat island effect as evidenced by its
statistically significant correlation coefficients. It has a significant impact on the
variations in land surface temperature. This study also highlighted the key
variations in how land use and cover affect LST. Across all time periods of
investigation. Therefore, techniques for remote sensing and geographic information
systems are useful for tracking and analyzing urban expansion patterns and
assessing their effects on land surface temperature.

Extracting, studying and interpreting the morphological database of a basin
is a basic building block for building a correct geomorphological understanding of
this basin. In this work, Arc GIS 10.8 software and SRTM DEM satellite images
were used. The principle of data integration was adopted by extracting the
quantitative values of the morphometric characteristics that are affected by the
geomorphological condition of the studied basin, then eliciting an optimal
conception of the geomorphological condition of the basin from the meanings and
connotations of these combined transactions. Hypsometric integration was
extracted for each region in the basin separately with the value of integration of the
plot curve for the relative heights of the basin regions with their respective regions.
Hypsometry coefficients reveal that regions (A, B, C, D, and F) are still in
their formative years, while region E is in the maturity stage and region G is in the
monadnock stage of the geomorphological cycle.

The choice of gate dielectric materials is fundamental for organic field
effect transistors (OFET), integrated circuits, and several electronic applications.
The operation of the OFET depends on two essential parameters: the insulation
between the semiconductor layer and the gate electrode and the capacitance of the
insulator. In this work, the electrical behavior of a pentacene-based OFET with a
top contact / bottom gate was studied. Organic polyvinyl alcohol (PVA) and
inorganic hafnium oxide (HfO2) were chosen as gate dielectric materials to lower
the operation voltage to achieve the next generation of electronic applications. In
this study, the performance of the OFET was studied using monolayer and bilayer
gate insulators. To model and analyze a device\'s electrical properties, MATLAB
was used. Two main parameters were studied: switching ratio (Ion/Ioff) and
subthreshold swing (SS), as well as the effect of dielectric capacitance on the gate
dielectric materials. The PVA/HfO2 bilayer gate dielectric gave the best results in
I
on/Ioff ratio, SS and transconductance of 9.0510-7, -1.52, and -4.99 x10-5A/V
respectively, which is because the dielectric capacitance has increased.

In this work, a Photonic Crystal Fiber (PCF) sensor based on the Surface
Plasmon Resonance (SPR) technology was proposed. A thin layer of gold (Au)
was deposited on a D-shaped Photonic Crystal Fiber (PCF), which was coated with
plasmonic chemically stable gold material with a thickness of 40nm. The
performance parameters like sensitivity including wavelength sensitivity and
amplitude sensitivity and resolution were evaluated by simulation using COMSOL
software. The proposed sensor was created by using the finite element approach, it
is numerically examined. The results show that the surface of D-shaped Photonic
Crystal Fiber coated with Au behaves as a sensor to detect the refractive index (IR)
of toxic metal ions. The impacts of the structural characteristics on the resonant
spectra are also researched in order to improve sensing performance. The greatest
amplitude sensitivity was 99.2 RIU-1 and maximum resolution was 4 x 10-5
RIU achieved within the detection range (1.351-1.363).