Journal of Education and Scientific Studies

This research aims to investigate the effect of laser pulse number on the optical properties
of iron oxide nanoparticles (Fe₂O₃ NPs) prepared using pulsed laser ablation in liquid (PLAL).
The particles were prepared in deionized water with varying laser pulse counts (500, 700,
900, and 1100) at an energy of 900 mJ. The UV-Vis absorption spectra showed an increase in
absorbance with increasing pulse count, indicating a higher concentration of nanoparticles in
the solution. The results also showed a decrease in transmittance and an increase in both the
absorption coefficient and extinction coefficient with increasing pulse count. Furthermore, a
gradual decrease in the optical band gap (Eg) was observed, which is attributed to the increas�
ing particle size and a reduction in the quantum confinement effect. These results indicate that
the optical properties of Fe₂O₃ particles can be controlled by adjusting the number of laser
pulses, making them suitable for various optical, sensing, and electrical applications.

In this study, the optical properties of pure and tin oxide (SnO₂)-doped cerium oxide
(CeO₂) thin films with different weight ratios (1, 3, and 5)% deposited on glass substrates
were investigated within the wavelength range of (300–1100) nm using the pulsed laser
deposition (PLD) technique.
The optical analysis results showed an increase in the absorbance and absorption coefficient values with increasing SnO₂ doping concentration. In addition, the results revealed
a decrease in both Transmittance and optical band gap values, which dropped from (2.87
to 2.59 )eV, indicating a shift in the Fermi level and an enhancement in electron transport.
Furthermore, the extinction coefficient, reflectance, and refractive index were found
to increase with higher SnO₂ doping levels. These improvements in the optical properties
suggest that the prepared films have potential applications in optoelectronic devices and
solar cells.

The optical properties of pure polyacrylonitrile (PAN) nanofiber films and those doped
with titanium dioxide (TiO₂) at a doping ratio of 0.5 wt% were investigated. The films
were deposited on glass substrates within the wavelength range of 250–1100 nm using the
electrospinning technique. The results showed an increase in absorbance upon doping with
titanium dioxide, accompanied by a higher absorption coefficient compared to pure PAN
fibers. A decrease in transmittance was also observed with the addition of TiO₂. Moreover,
the optical band gap decreased to the range of 3.78–3.88 eV upon doping, along with an
increase in the extinction coefficient. These enhancements in optical properties indicate the
potential applicability of these films in optoelectronic devices and solar cell applications.

In this paper, thin films of tin oxide nanoparticles (SnO2) were prepared using pulsed
laser deposition (PLD). The optical properties were investigated by calculating the absorbance, transmittance, absorption coefficient, and optical band gap when cadmium-telluride
was mixed with tin oxide at weight percentages of 0%, 20%, 40%, and 60%. The results
showed that cadmium-telluride doping significantly affected the optical properties of the
SnO
2 films. A decrease in absorbance and absorption coefficient was observed with increasing CdTe content, while the transmittance gradually increased. Furthermore, the optical band gap decreased from 2.799 eV for the pure sample to 2.067 eV at a 60% doping
concentration, indicating the possibility of controlling the material’s properties by adjusting the doping ratio. This change results from the formation of a heterostructure between
the two materials, leading to improved photon absorption and reduced photon loss through
recombination processes. The results also demonstrated that the technique is effective in
preparing homogeneous nanofilms with enhanced optical properties, making them promising candidates for application in solar cells, optical sensors, and optoelectronic devices.

In this research, the optical properties of hybrid thin films composed of silver oxide
(Ag₂O) and graphene oxide (GO) were prepared and investigated using the pulsed laser
deposition (PLD) technique. The preparation process was carried out by mixing the
powders using ultrasonic waves, then pressing them into a solid target for deposition
onto glass substrates. The resulting films were examined using a UV-Vis spectrometer over the wavelength range of 300 to 1100 nm. The results showed that the absorbance was high at short wavelengths (<400 nm) and gradually decreased with increasing
wavelength, while the transmittance increased with increasing wavelength, reflecting
the typical optical behavior of semiconductor materials. The study also demonstrated
that increasing the laser power and the number of pulses during deposition contributed
to a decrease in the optical energy gap.

This study aimed to evaluate the effect of adding low percentages of aluminum oxide (Al₂O₃) to
Cu–Al–Ni alloy powder on improving the physical properties of the coating deposited on stainless
steel using flame-spraying technology. The results showed that reinforcing the coating with Al₂O₃
particles at percentages ranging from 0% to 12% resulted in a significant decrease in water absorption and apparent and true porosity, indicating a reduction in open pores and better particle compaction within the coating. An increase in both apparent and true density was also observed with
increasing Al₂O₃ content, reflecting an improvement in the microstructure of the deposited layer
and an increase in solids content. These results confirm that Al₂O₃ addition is an effective method
for improving the quality of metallized heat-treated coatings, increasing their resistance to moisture
and corrosion from environmental factors, making them suitable for industrial applications requiring high-strength, low-permeability coatings. In addition, an overall improvement in hardness
(Vickers hardness) was observed at all studied ratios with increasing Al₂O₃ reinforcement. The
highest hardness value was obtained at a 12% Al₂O₃ reinforcement ratio, reaching approximately
304.23 kg/mm². These results confirm that the addition of Al₂O₃ is an effective way to improve the
quality of metal thermal coatings, increasing their resistance to moisture, corrosion, and abrasion,
making them suitable for industrial applications requiring high-strength and durable coatings.

In this study, natural radioactivity was measured in chicken meat samples from different areas of Dhi-Qar Governorate using a germanium detector. The measurement
results showed that the average specific radioactivity of the elements )K-40, U-238,
and Th-232) was )26.696 Bq/kg, 9.277 Bq/kg, and 11.045 Bq/kg), respectively. Other
relevant standards, such as )Raeq, D
ɣ
, )AED( in, , )AED(ou, , Iɣ, Hin , Hex), were also
measured in ten chicken meat samples. As the results showed, these were lower than
the recommended values for specific radioactivity set by UNSCEAR )2000(

In this work, a new photocatalyst K2Fe4O7 was successfully prepared by hydrothermal treatment )Hydrothermal processing(. The prepared compound was applied to break
down and remove methylene blue )MB( contaminants under xenon light. The prepared
compound was characterized using X-ray diffraction (XRD), Fourier transform infrared
spectroscopy )FTIR(, scanning electron microscopy )SEM(, and ultraviolet-visible absorption spectroscopy (UV-VIS) techniques to study the structure, composition, shape,
and optical properties of the photocatalyst. Visible ultraviolet (UV-VIS) results showed
significant decomposition of methylene blue (MB) pollutants under xenon light, reaching a decomposition rate of )85%( under xenon light in )72 minutes(. It has been shown
that the interaction between different semiconductors facilitated the development of this
compound. In addition, the blue displacement results in the visible light absorption range
enhanced the compound’s photocatalytic efficiency and as a promising visible light photocatalyst for real-world wastewater treatment. The results indicate that K2Fe4O7 is a
promising material for treating real wastewater under visible light

In this research, thin films of pure zinc oxide (ZnO) and aluminum oxide (Al₂O₃) doped
with varying percentages (0, 1, 2, 3, and 4%) were prepared using the thermochemical spray
technique on glass substrates. Optical measurements showed that the absorbance is high at short
wavelengths, reaching its highest value at a wavelength of approximately 328 nm. The 4% doped
sample exhibited high absorbance compared to the pure sample, which showed lower absorbance.
The absorbance then gradually decreased to relatively low and stable values within the range of
700–1100 nm due to the incident photon energy being below the energy gap of the films.
Transmittance exhibited behavior opposite to that of absorbance. The pure sample recorded
the highest transmittance of 97.08% at longer wavelengths, decreasing to 68.08% at shorter wavelengths. Transmittance decreased significantly with increasing doping levels, reaching 60.13% at
a 4% doping concentration, due to increased light scattering and a higher density of electronic
states within the crystal structure.
The optical gap of the pure sample was 3.18 eV, while it gradually decreased with increasing
doping, reaching 2.76 eV at a 4% doping concentration. This decrease is attributed to the introduction of additional energy levels within the gap, resulting from the substitution of Al³⁺ ions for
Zn²⁺. This substitution narrows the optical gap and shifts the optical edge towards longer wavelengths.

The chemical precipitation method was used to prepare two-phase ferrite composites
with the chemical formula )CoFe2-xMnxO4( and weight ratios )x=0.0, 0.4, 0.8, 1.4, and 2(.
X-ray diffraction (XRD) studies revealed that the ferrite maintained its cubic spindle structure with slight peak shifts upon Mn doping, reflecting lattice expansion and microstructural changes, accompanied by a decrease in crystal volume and an increase in surface area,
dislocation density, and microstresses, enhancing the potential for fine structural tuning.
Scanning electron microscope (SEM) images confirmed the evolution of the crystal structure from homogeneous spherical shapes to coarser and more densely packed structures
with increasing Mn content. At the same time, EDS elemental analysis highlighted the
successful incorporation of Mn into the ferrite crystal lattice, with a balanced distribution
of Pb, Zn, Mg, Co, Fe, Mn, and O in the hybrid systems, ensuring good structural homogeneity.

This research investigates the effect of pulse number and annealing temperature on the
optical properties of ZnO nanofilms prepared by pulsed laser deposition (PLD). The results
showed that increasing the pulse number from 100 to 300 pulses resulted in a decrease in the
absorbance in the UV region, especially at wavelengths below 400 nm. It was also observed
that the optical transmittance gradually increased with increasing pulse number and annealing
temperature, indicating an improvement in the film density and quality. Furthermore, the optical energy gap increased with increasing annealing temperature and pulse number, resulting
from improved crystallinity, increased grain size, and the emergence of localized energy levels
near the valence and conduction bands. These results demonstrate that controlling the pulse
number and temperature can be effectively used to tune the optical properties of ZnO films for
microelectronic and optical applications.

Protoplanetary disks are the birthplaces of planets and are governed by complex
hydrodynamical and physical processes. Among the various instabilities influencing
disk evolution, the Rossby Wave Instability (RWI) plays a critical role in generating persistent vortices, which can facilitate planetesimal formation and shape disk
structure. This review synthesizes current understanding of the fundamental hydrodynamic equations governing disk dynamics The conditions required for the onset
of RWI particularly the behavior of vortensity, extrema, and disk parameters such as
aspect ratio and viscosity, that most strongly affect instability That strongly affect instability growth like aspect ratio and viscosity theoretical and observational contexts
are discussed, Discussed illuminating the central criteria for RWI and its broader
significance in the context of planet formation.

In this study, A theoretical model of the top–gluon interaction is introduced based on
Quantum Chromodynamics theory (QCD). The emission rate of photons as a function of
various parameters is studied. The Bag constant B1/4 = 235,355MeV, system temperature in
rang (190-310MeV), fugacity of quark and gluon גQ =1, גG=0.04 and photon energy in rang
(0.75-7.5GeV) are used to calculate the yield of photons for t????→ d????, t???? → b???? systems
at bremsstrahlung processes. It was found for each system, the photons rate at calculated
critical temperature from B1/4 =235MeV is less effective than the photons rate at calculated
critical temperature from B1/4 =355MeV. For two systems, the photons emission rate is
directly proportional to both the flavor number and system temperature and inversely proportional to the energy of photon and the coupling strength.

The discovery of lasers is one of the most important innovations in the physics
world, given the effectiveness of the laser beam that outstrips any of the technologies
that are used today, Dentistry is a significant use the technology of laser. This survey
the different applications of lasers in dentistry including types of lasers, laser-tissue
interactions, treatment, and diagnosis. Laser in dentistry is ingoing a new age of legitimacy, fuelled by the adaptability and broad efficacy of the laser. and its applications
work for multiple dental treatments and have become a necessary and important tool
in the context of processing. Being more precise, faster, and less expensive, lasers
have penetrated most dental specialties over the past half-century, including oral surgery, root canal treatment, periodontics, pediatric dentistry, prosthodontics, and orthodontics. In many ways, lasers revolutionized the diagnosis and treatment of diseases

Radon gas is a major indoor air pollutant, is found inside and outside buildings, and is the
main cause of lung cancer. Therefore, determining its concentration levels and the dose resulting from inhalation of this gas is important for the public health of people inside buildings.
The aim of the research includes measuring radon gas concentrations in the air inside and
outside the building of the College of Education at Iraqi University using a nuclear trace detector (CR-39). The detector (1x2) cm2 was exposed for a full month during the winter because
this period roughly represents the official working hours at the college. It is clear from the
results of the study that the concentrations of radon gas inside buildings are higher than their
concentrations outside buildings, and this increase in concentration is due to the fact that the
walls of buildings are the main source of radon generation inside buildings, as it was shown
that building materials have played an important role in increasing the concentrations of radon
gas inside buildings in addition to the age of the buildings and the height above ground level.
The annual equivalent dose values for exposure to radioactive radon gas and its effect on
the lungs ranged between 0.43 and 1.34 mSv/y and an average of 0.86 mSv/y. These values are
the lowest allowed by ICRP (3-10) mSv/y.

This research deals with the study and simulation of a perovskite-based solar cell
(CH₃NH₃PbX₃) using SCAPS-1D software, to analyze and improve their conversion efficiency by introducing multiple back-reflection layers, and to test the effect of the type
and thickness of these layers on the cell’s photovoltaic performance. The simulations were
performed using a conventional cell structure, then gradually modified by adding materials
such as Sb₂Se₃, Si, SnS, CIGS, Sb₂S₃, and ZnTe, and the results of each were compared
with the original cell.
The results showed that some materials were more effective than others in improving
cell performance, with the layer outperforming ZnTe is clearly shown to have the highest
conversion efficiency of about 28.4% at an optimal thickness (1.42 µm). It was also shown
that the improvement of open voltage (Voc), short-circuit current (Jsc) and fullness factor
(FF) was possible by using materials with a wide bandgap and optical and electrical compatibility with the perovskite layer.
The study also demonstrated that the thickness of the back-reflection layer plays a
significant role in enhancing the absorption of long-wavelength photons, reducing optical
loss, and improving carrier collection. However, it was noted that there is an optimal limit
to this thickness, as increasing it beyond a certain level does not lead to significant additional improvement and may even cause increased resistance or internal losses.

In this study, a theoretical simulation was conducted to improve the performance of a solar cell with a
structure. ZnSnS/Cu by analyzing the effect of the back-reflection layer, varying its thickness, and doping. The
results showed that introducing a back-reflection layer is an effective strategy for increasing solar cell efficiency by enhancing the internal reflection of unabsorbed photons and redirecting them toward the absorber layer.
Several materials have been tested as back reflective coatings such as:Si, Sb₂Se₃, Zn₂P₃, CIGS, and
ZnTe. ZnTe showed superior performance across all cell parameters, with higher open-circuit voltage (Voc),
short-circuit current (Jsc), and fill factor (FF), achieving a maximum photovoltaic efficiency of 29.26% compared to the reference value of 11.23%.
The results of changing the layer thickness also showed thatZnTe has an ideal thickness of 1.60 µm that
achieves the optimal balance between optical and electrical properties, contributing to improved carrier extraction and reduced losses due to interference or random reflections.
ZnTe was preferable because it has high reflectivity and a wide energy gap, which returns unabsorbed
photons to the absorber layer and reduces charge loss, resulting in a significant improvement in cell efficiency.
As for doping the reflection layer, it has been shown that it contributes to tuning the electronic properties
at the backside of the cell, by improving conductivity and reducing recombination rates. Doped ZnTe is the
most compatible in terms of electronegativity, carrier speed, and state density, making it the ideal choice for
backscattering layers.
These results confirm the importance of careful layer design for thin-film solar cells, and the need to
fine-tune the reflective layer properties in terms of material, thickness, and doping, to achieve high and stable
conversion efficiencies.

This study aimed to produce bone-like materials by investigating the radiation
dose rate and mass attenuation coefficients (MACs) of eight metal-organic epoxy
samples reinforced with different amounts of sodium chloride (NaCl). Gamma rays
with an intensity of 60, 186, 242, 295, 352, 609, and 662 keV were used. These
rays came from nuclear sources emitting 241Am, 226Ra, and 137Cs isotopes. A NaI(Tl)
gamma ray detector was used to perform the measurements. The results showed that
increasing the amount of the (NaCl) activator slowed the radiation dose rate. On the
other hand, increasing the power and efficiency of the source significantly increased
the dose rate. With a difference of less than 3%, the observed (MAC) values were
very close to the figures reported in ICRU Report No. 44. The results demonstrate
that the manufactured composite materials can be used in place of conventional materials for dosimetry tasks, and can also be used in place of conventional materials to
make tissue phantoms for medical and imaging studies.

This research examined three different ways to calculate energy gap values based
on temperatures:Cluster analysis, the Neville method, and a hybrid model that combines the two methods. Cluster analysis relied on grouping data into similar groups and
converting complex equations into linear formulas to facilitate calculations, with an average error of about (0.0315) Volts, with standard deviation (0.0266) Volt. The Neville
method, which approximates numerical values using polynomial equations, showed
higher accuracy, with errors ranging from (0.01–0.02) Volts, with standard deviation
(0.008) Volt. In contrast, the hybrid model, which combined the two methods, was
distinguished by using a correction coefficient (L = 0.5), with the highest level of accuracy, where the error ranged from(0.001–0.06) Volts, with standard deviation(0.01573)
Volt.

Third order nonlinear optical (NLO) material is vital in ultrafast photonic applications including optical switching, optical modulation and optical limiting. The organic solvents such as Toluene, Chloroform,
and Acetone provide cheap and tunable substitutes of the traditional inorganic NLO materials, but without
comprehensive comparative investigations conducted in controlled experimental conditions. The paper is
important because it will fill the gap in detailed data of the third-order nonlinear optical characteristics of
organic solvents namely Toluene, Chloroform, and Acetone. It will offer comprehensive comparisons of the
performance of these solvents in nonlinear optics by analyzing their performance using dual-laser Z-scan
analysis, as this is a gap in research. A dual-laser Z-scan methodology was used in this study to measure the
NLO characteristics- nonlinear refractive index (n2), absorption coefficient (β) and third order susceptibility
(χ³). The measurements have been done at a temperature range of - 20 0 C to 60 0 C and the results have been
compared with CS2 and engineered polymers. The error margin considered all the experimental readings by
5 percent. Toluene and Acetone demonstrated superior NLO performance, with average values of n2 ≈ 2.29
× 10-¹¹ cm²/W, β ≈ 2.3 × 10-5 cm/W, and χ³ ≈ 5.2 × 10-6 esu. Chloroform always exhibited the lowest values.
The thermal stability of Toluene and Acetone was proven by the fact that temperature-dependent results were
obtained. These solvents have a balanced NLO strength and environment friendliness as compared to CS2
and polymers. The results confirm Toluene and Acetone as good candidates of nonlinear photonic systems.
They are more practical in the optical devices of the real world by virtue of the fact that their performance
is stable to thermal change. The results will improve the knowledge of the influence of molecular structure
on NLO behavior, which will serve as an important contribution to the production of materials that are environment-friendly and cost-effective to be applied in high-speed photonic devices such as optical switching
and optical limiting.

In this research, particles were prepared.Fe₃O₄ nanoparticles were prepared using papaya extract in its
aqueous and alcoholic forms, coated with varying proportions of chitosan (5%, 10%, 15%), with the aim of
studying the effect of the nature of the extract and the proportion of chitosan on the structural, morphological
and magnetic properties of the particles.
X-ray diffraction results showed(XRD) showed that all samples maintained the typical inverse cubic
crystal structure of iron oxide Fe₃O₄. The highest crystal size was recorded in the samples prepared with the
aqueous extract at 15% chitosan, reaching approximately 152.7 nm, while it decreased to 100.4 nm in the
alcoholic samples at the same ratio, reflecting the ability of the alcoholic extract to inhibit crystal growth due
to its effective surface interactions.
In morphological analysis using scanning electron microscopy(SEM) The alcoholic samples also showed
smaller particle sizes of 67.0 nm, compared to 74.0 nm in the aqueous samples at 15% chitosan, demonstrating the effectiveness of the alcoholic extract in reducing particle size and enhancing their nanoscale distribution. TEM analysis supported these results, showing a gradual decrease in particle diameters to 10.1 nm in
the alcoholic system, with a clear shift in shape toward regular spherical shape.
The magnetic properties measured by the techniqueVSM revealed ferromagnetic behavior for all samples, with the highest magnetic saturation recorded in the 5% alcohol chitosan sample, reaching 63.2 emu/g,
while this value gradually decreased with increasing chitosan. In contrast, the highest magnetoresistance
(Hc) was recorded in the 15% aqueous sample, reaching 140 Oe, demonstrating the bioencapsulation effect
on resistance to remagnetization.

Reliable internet connectivity is vital for emergency communication and disaster
management, yet many remote and rural regions remain without access to stable networks. This study presents a simulation-based framework for deploying Unmanned
Aerial Vehicles (UAVs) to establish temporary internet connectivity in such regions.
The proposed system employs a terrain-aware deterministic region-filling algorithm to
determine optimal UAV placement, ensuring full coverage with minimal energy consumption and latency. UAVs act as aerial base stations operating within altitude and energy constraints, and the deployment is optimized to balance leftover energy among all
drones. Simulation experiments are performed using MATLAB, NS-3, and OMNeT++
on the Pettimudi landslide region in Kerala, India. Results demonstrate that 100% coverage of a 4×4 km² disaster area can be achieved with only sixteen drones, maintaining
network efficiency of 98% and latency below 200 ms. Comparative analysis with traditional planar UAV, satellite, and Cell-on-Wheels (COW) systems highlights superior
scalability, energy efficiency, and deployment speed. The proposed model provides a
reproducible and practical solution for rapid communication restoration in remote or
disaster-affected regions.

The objective of this study was to assess the biological effect of X-rays on the growth of E.
coli, a widely used model for the studies of radiation effects. Bacterial suspensions were irradiated with doses of 0, 0.5, 1.0, 2.0, and 4.0 Gy from a standard medical X-ray device. Afterward
they were plated on nutrient agar media and kept at 37°C for 24 h.
The number of bacterial colonies decreased progressively as the radiation dose increased.
The control group had an average colony count greater than the radiation groups, the minimum average was for the 4.0 Gy group. The differences between the groups were evaluated by
one-way ANOVA and two-way t-test and they were highly statistically significant (p < 0.001),
reflecting an association between the radiation dose and the bacterial growth inhibition.
This bio-effect shows that X-radiation can produce cellular damage via breaking DNA and
generating ROS (reactive oxygen species), causing disorganization of the bacteria vital functions particularly, at a dose bigger than 1.0 Gy. A few outliers in the statistical distribution also
showed variation at the individual level of bacterial response and set the stage for additional
molecular analyses to investigate mechanisms of adaptation or resistance.
This work confirms that X-rays may be a useful means for sterilizing microorganisms,
whose effective doses will be value determined, to prevent the interference with life of biological systems. Our findings are an informative qualitative contribution to a mechanistic understanding of the connection between ionizing radiation and cell functions in microorganisms.

Free Space Optics (FSO) is a technology that complements and provides an excellent alternative to fiber optic and radio wave communication systems in specific circumstances such as
natural disasters and large events due to its ease of installation, low cost, and ideal performance
in normal atmospheric conditions, especially when a suitable wavelength is available, as it is
a means of transmitting data from one point to another. In this study, we present a laboratory
and field study to study the extent of the impact of different atmospheric conditions on the
performance of the free space optics system using a 532 nm laser. This was done in two parts:
the first was inside the laboratory inside a two-meter-long glass chamber, and the laser beam
was passed once loaded with digital signals, including a signal, and once without data, through
different atmospheric disturbances and at varying levels from weak concentration to very high
concentration, simulating difficult natural conditions in harsh environments and conditions. The
second part of the research consists of a field experiment with a 532nm laser in a real environment and a distance of 50 meters in the summer and at different times of the day. This is to prove
and enhance the laboratory experiment that was conducted and to enhance the work. An FTIR
examination was conducted on both the dust and smoke samples that were used in the laboratory
to provide a comprehensive view and explain the reasons for signal attenuation more accurately.
The research aims to focus on free-space optics systems as a promising alternative in difficult
conditions and the possibility of developing this technology by identifying the reasons for the
attenuation of the transmitted signal and the possibility of reducing the attenuation that occurs
in the transmitted signal.