Iraqi Journal of Physics

This work investigates the photon radiation shielding efficiency of selected perovskite
ceramics, halide-based double perovskites and organic-inorganic halide perovskites,
using computational modeling across the photon energy range 0.015–15 MeV. The
investigated parameters are Mass Attenuation Coefficient (MAC), Linear Attenuation
Coefficient (LAC), Half Value Layer (HVL), Tenth Value Layer (TVL) and Mean Free
Path (MFP). The results are based on the total interaction cross section contributions
of photon-matter interactions. They reveal that the shielding efficiency of these
materials is strongly influenced by their elemental composition, density, and photon
energy. Two software tools, Phy-X/PSD and NGCal, were employed in the study to
verify the accuracy of the calculations. The results from the two software tools are
found to be in good agreement, with a difference in values of less than 0.1%. Halidebased
double perovskites exhibited superior attenuation properties at low and
intermediate photon energies due to their high-Z elements and relatively high density,
while organic-inorganic halide perovskites displayed moderate shielding efficiency,
limited mainly by lower density and lighter elemental composition. Yet, they remained
attractive due to their tunability and potential for lightweight shielding applications.
Overall, halide double perovskites offered the most promising radiation shielding
performance among the studied materials. In particular, those containing heavy atoms,
such as Pt (Z = 78), stand out as excellent photon-shielding candidates. Therefore,
perovskite ceramics have significant potential as next-generation photon shielding
materials. Future research should focus on experimental synthesis and long-term
stability under radiation exposure to accelerate the practical deployment of perovskite
ceramics in radiation applications.

Light isotopes, especially closed-shell nuclei, have significance in thermonuclear reactions of the Carbon-Nitrogen-Oxygen (CNO) cycle in stars. In this research, radiative proton capture of 15N(p,γ)16O was calculated using MATLAB codes to find the reaction rate across a temperature range up to 10 GK for the spectrum\'s non-resonant part, and the astrophysical S- factor S(E) only at low energies (E=70 keV). The findings were compared with conventional reactions before and after statistical analyses, and the results were acceptable when compared to earlier compilations and reference libraries. For temperatures 0.07 < T9 < 0.09, current direct data cover 50-90 % of the region under the Gamow peak. At T9 < 0.15,non-resonant capture becomes more important, and the current rate is up to 40 % lower than NACRE-II due to lower S factor values than the NACRE-II extrapolation. For energies E < 70 keV, a linear relationship for the S-factor was assumed.

Pure polyvinylpyrrolidone (PVP) nanofibers were doped with different concentrations of gold nanoparticles (Au NPs) using the electrospinning technique. The characteristics of both nanofibers were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and UV-visible properties. The structure of PVP-Au was amorphous, as revealed by XRD. A DC voltage of 20 kV was applied to Au-PVP nanofiber beads on glass substrates and silicon wafers of n-Si type, oriented (111), at room temperature. The effect of doping on some physical properties (structural, optical, electrical, and sensitivity) of the polymer material was studied. The physical properties of the material composite film fibres were studied as the concentration of Au rises. The optical energy gap for three Au-PVP samples ranged between 3.60 and 3.70 eV. The responsivity for Au-PVP nanofibers was obtained for the UV detector, where the optimum detector sensitivity was at the wavelength of 360 nm. The sensitivity values obtained were 2.4, 17.5, and 24.45 for doping ratios 0.1:9.9, 0.5:9.5, and 1:9, respectively, with the values of the rise time ranging from 2.40 to 24.45s and fall time 10.2- 22.3s for Au concentrations.

This study involved the preparation of polyaluminum chloride (PAC) from basic materials and elements, namely aluminum flakes (pure and impure), by dissolving them in hydrochloric acid diluted to 50%. The flakes were added gradually to ensure the formation of a PAC solution with high specifications and efficiency in treating turbid water and forming heavy flocs as one of the important applications for removing turbidity and some elements from drinking water and wastewater. This method was verified using a turbidity meter and the application mechanism using a jar-test apparatus. The analyses showed that the efficiency and sedimentation speed reached 95% for high turbidity levels and 98% for low turbidity levels. X-ray diffraction (XRD) analyses clarified the compounds present in both pure and impure materials, and the purity of the material was determined using a UV device. The results indicated the purity of the substance in the solution prepared from pure materials and the level of impurities in the solution prepared from impure materials (poly aluminum), as well as the efficiency variation according to the alkalinity of the solution. Additionally, Fourier Transformation Infrared spectrometer (FT-IR), an atomic absorption spectrometer, and a titration meter for chlorine measurement were used. The comparison between PAC and alum showed the potential of PAC as an ideal and highly efficient alternative.

This study investigates the electrical and optical properties of polyaniline (PANI) composites incorporating graphene oxide (GO) and metal oxides such as tin dioxide (SnO₂) and tungsten trioxide (WO₃). The addition of GO improves charge transport due to its high surface area and conductive nature. Moreover, SnO₂ contributes to stabilizing the electrical conductivity of the composites over time, while WO₃ introduces frequency-dependent charge-trapping behavior that influences dynamic electrical responses. Optically, GO modifies the bandgap and enhances UV-visible light absorption through improved photon interaction. SnO₂ improves the spectral stability of the composites, and WO₃ fine-tunes the wavelength-dependent optical response by selectively interacting with incident light. The key novelty of this research lies in the synergistic integration of GO with both SnO₂ and WO₃ within the PANI matrix, which allows for a simultaneous and balanced enhancement of both electrical and optical properties. This multifaceted improvement results in nanocomposites with strong potential applications in advanced technologies. The findings suggest promising use in optoelectronic devices, chemical sensors, and printed electronic systems, thereby supporting the development of multifunctional materials for next-generation smart technologies.

To evaluate the efficacy of the Erbium Chromium-Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) laser in sealing dentinal tubules with the incorporation of multi-walled carbon nanotubes (MWCNTs) paste, and without, when used on exposed dentin. Thirty-nine natural posterior teeth were prepared, sectioned, cleaned, and made ready for treatment. Samples were split into 3 groups: Group G1 is the control group (N=10). Group G2 (N=10) was exposed for 2 seconds to a 2780 nm Er,Cr:YSGG laser (Waterlase iPlus, Biolase Technology) in the free-running pulse mode, with 0.25 W power, 20 Hz frequency, a pulse width of 60 μs, a fibre tip size of 600 μm, and non-contact mode, and Group G3 (N=10) was exposed to Er,Cr:YSGG with carbon nanotubes (CNTs) paste along with a pilot research group (N=9). Scanning electron microscopy (SEM) was used to analyze dentinal surfaces. SEM micrographs were obtained after treatment. A qualitative evaluation of the SEM micrographs was conducted to analyze the changes in surface features and calculate the mean difference of tubule occlusion between the groups. The SEM micrographs showed a decrease in the mean diameter of dentinal tubules from 3.13 µm in the control group to 0.733 µm in group G2, whereas group G3 had a diameter of 0.292 µm. The selected parameters of the Er,Cr:YSGG laser (0.25 W/2 s, 70 W/cm²) for groups G2 and G3 were effective in reducing and plugging any exposed dentinal tubules, with the highest effect for group G3 without any sign of fissures or cracks.

In this study, the Single-Mode Fiber (SMF) was examined in a theoretical investigation of the impact of the medium on the two Whispering Gallery Mode Resonator (WGMR) models using MATLAB software. It was found that the Free Spectral Range (FSR) has an inverse relationship with the resonator radius, and it was equal to 0.33 THz. The low FSR value is caused by the big microsphere resonator. A high Q-factor is defined as 0.175 x 105. The resonance spectrum was found to diminish when the surrounding media's refractive index rose. The WGMR's evanescent field interacts with the external medium more strongly when the surrounding environment’s refractive index increases. The resonant modes' boundary conditions were altered by this interaction, which raises the modes' effective refractive index. The WGMR resonance frequency may also shift as a result of changes in the surrounding medium refractive index. To achieve high-resolution sensing, the surrounding medium of the spherically shaped WGMR was altered at a step of 0.002 in the range of 1.33 to 1.35. As for the sensitivity value, a value of (-) 100.152 THz/RIU was obtained, which is considered a good value for use as a sensor.

Ion engines, also known as plasma engines, are a cutting-edge technology for space propulsion that is continually evolving. In this work, a static magnetic field is used in a cylindrical engine placed inside a vacuum chamber at 0.2 mbar, with argon gas, an applied voltage of 5 kV, and an engine power supply of 25-100 watt. The shape and intensity of the magnetic field determine the ion thruster's discharge performance. A cylindrical ion engine was constructed with dimensions of 5, 5.5, and 0.7 cm in length, width, and thickness, respectively. The coil of the ion engine generates a static magnetic field of 9 and 25 mT. This system was used to study the effect of the magnetic field on the ionization rate and plasma distribution. The results showed that the cylindrical magnetic field confined the energetic electrons primarily near the centre of the engine and resulted in an increased ionization rate in this region. The Langmuir probe is used to diagnose plasma parameters, including temperature and density, with and without a magnetic field. The electron density in the centre of the ion engine increased in the presence of the magnetic field 2-6x1019 m-3, while the electron temperature decreased 2-4 eV. The use of a magnetic field reduces the energy consumption of the ion engine and the energy expended to generate plasma, making it suitable for spacecraft

This study investigates the effect of Dielectric Barrier Discharge (DBD) plasma on the inhibition of bacterial growth. The DBD plasma system operates with a high-voltage power supply at a frequency of 8.4 kHz and an AC voltage of 20 kV. The study utilized two strains of pathogenic gram-positive bacteria, Streptococcus mutans and Enterococcus faecalis. The bacterial species were split into two groups at two distinct dilution levels (108). Following a series of dilution steps ranging from 101 to 109. The bacteria were subjected to DBD plasma treatment for different durations (0.5, 1, 1.5, 2, and 2.5 min). The Dielectric Barrier Discharge (DBD) plasma treatment resulted in a statistically significant increase in bacterial death (P < 0.05) compared to the control group. Exposure to DBD plasma effectively resulted in bacterial kill; longer treatment durations yielded greater bacterial inactivation. These results demonstrated the potential of DBD plasma in clinical and environmental applications for bacterial control.

Dust storms frequent in Iraq can have far-reaching consequences for the distribution and abundance of heavy and trace elements within the soil, ultimately influencing the dynamics of ecosystems. This study aims to identify the sources of the severe dust storm in Iraq on May 16, 2022, and assess the heavy element pollution and their environmental impacts. The results revealed that the hybrid-single-particle-Lagrange-integrated trajectory (HYSPLIT) model trajectory of the dust storm agreed with MODIS visuals. The primary dust storm sources are identified as follows: the first source is from the shared border region between Syria (south of Rif-Dimasshq) and Jordan (north of Al-Ruwaished), and the second is from the northwestern area of Iraq, specifically north of Anbar and south of Nineveh. The dust samples mainly consist of clay, sand, and metals, according to particle size analyses, with sizes ranging from 6 nm to 50 µm and increasing the concentrations of trace elements, which affect the ecosystem and the possibility of changing soil properties and increasing the amounts of heavy metals that adversely affect the environment and human health. The contamination factor values showed very high pollution for the elements (Ni, Ge, Se, Mo, Ag, Cd, Sb, Te, I, Hg, and Bi). The I-geo index indicated it was extremely polluted with heavy elements (Ge, Te, I, Hg, Bi, and Se). Using the contamination factor values for the elements (Pb, Ni, Cd, Zn, Cu, Cr, Hg, and Fe), the pollution load index was found to be 2.68, indicating environmental pollution.

This research aims to develop an automated system for detecting built-up areas in rural regions, addressing challenges in accurately identifying residential buildings. One of the main difficulties lies in distinguishing between building surfaces, streets, and unpaved roads, as they exhibit similar brightness levels. In this study, high-resolution RGB satellite images from World View-2 satellite with a spatial resolution of 0.46 m were utilized, and an automated system for detecting built-up areas was developed. The system extracts 13 discriminative features categorized into pixel-based and area-based metrics to enhance the differentiation between buildings and non-built-up areas. These features include color-based metrics, such as the average gray value, greyness1, and greyness 2, which capture variations between color channels, as well as hue calculations derived from advanced equations to improve surface distinction. Additionally, local statistical metrics, contributed to refining detection accuracy by reducing noise. These features were selected based on their effectiveness in handling the variability in building materials and textures commonly found in rural environments. Furthermore, an Artificial Neural Network (ANN) classifier was trained to distinguish between built-up and non-built-up areas. To further enhance detection accuracy, post-processing techniques, including median filtering, gap removal, and eliminating irrelevant narrow slices were incorporated. The system's performance was evaluated using accuracy, precision, recall, and F1-score metrics to ensure the robustness and reliability of the building detection process. The results demonstrated that the ANN classifier effectively detects buildings while overcoming challenges posed by irregular shapes and varied surface characteristics.

The research demonstrates that perovskite methylammonium lead iodide (MAPI) can detect various hazardous and polluting chemicals, including ammonia gas (NH3), in the environment. To enhance the sensitivity, response time, and modify the structural properties of pure MAPI, zinc sulfide (ZnS) is incorporated in three different concentrations (1, 2.5, and 5wt%). The sensitivity of these ZnS-doped samples is evaluated for detecting NH3 and alcohol vapor. Sensors based on MAPI:ZnS composites are fabricated on writing paper samples using a solution-processing technique. Upon exposure to NH3, MAPI undergoes a colorimetric change from black to yellow. This phenomenon is attributed to the degradation of perovskite(MAPI) halides into lead (Pb) halides through the preferential adsorption of NH3 molecules. The structural properties were analyzed using X-ray diffraction (XRD) patterns, which revealed a slight shift in the diffraction peaks towards higher 2θ angles. Field Emission Scanning Electron Microscopy (FESEM) images displayed rod-like morphologies, with an average diameter of approximately 49 nm for pure MAPI and around 46 nm for the ZnS-doped samples.

In this work, gold/ titanium oxide: cadmium sulfide (Au/TiO₂:CdS) thin film nanocomposites as photocatalysts were synthesized using the sol-gel technique and deposited on glass substrates using the dipping method for the degradation of Methylene Blue (MB) dye in water. The CdS doping with TiO2 at ratios 1:1, 0.25, and 0.5 wt%. Au/TiO₂: CdS thin film characterization was achieved using X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy, field effect electron scanning microscopy (FESEM), and UV-Vis spectroscopy. The results of XRD showed that the obtained phase of TiO₂: CdS was cubic. The results of AFM showed that the distribution of grain sizes increased with increasing CdS concentration, as did the roughness and RMS. The FESEM results indicated that the particle size decreased from 58.68 nm to 22.24 nm as the concentration of CdS increased. Raman spectroscopy revealed that the TiO₂ peaks appear only at 1300 cm⁻¹ (B1g), 1600 cm⁻¹ (A1g), and 2000 cm⁻¹ (Eg). The optical properties were enhanced after the addition of CdS. The photocatalytic decomposition of Au/TiO₂: CdS thin films was investigated by the degradation of MB dye in water under ultraviolet (UV) light exposure. The results showed excellent photocatalytic performance after the addition of CdS.

Two samples of γ–mesoporous alumina (0.3M/m-Al2O3 and 0.5M/m-Al2O3) were prepared using the microemulsion method, with aluminium sulphate serving as the alumina precursor. The raw materials for microemulsion are sodium dodecyl sulphate (SDS) as the surfactant, 1-butanol as a cosurfactant, and n-hexanol as the oil phase. Scanning Electron Microscopy (SEM), BET surface area, BJH porosity of the samples, and their N2 adsorption-desorption isotherms at 77 K. The X-ray diffraction (XRD) and AFM techniques were used to characterize these samples. The results show that the two samples have identical phase structures and perfect indexing to the γ-Al2O3; the 0.3M/m-Al2O3 sample has a larger surface area, 229.18 m2 g-1, pore diameter, 5.59 nm, and pore volume, 0.32 cm3.g-1, than the 0.5M/m-Al2O3 sample. The morphology of the two samples was small spherical particles aggregated in spherical agglomerates, but the 0.3M/m-Al2O3 sample displayed smaller particles than the 0.5M/m-Al2O3 sample; the percentage of aluminium oxide was high, equal to 95.5% and 97.3% by weight for the 0.3M/m-Al2O3 and 0.5M/m-Al2O3, respectively. As a model, the 0.3M/m-Al2O3 sample was used as a carrier for delivering the ciprofloxacin drug. The loading was performed using the impregnation method, while the release was achieved through a dialysis bag with buffer solutions at pH levels of 7.4 and 5.4. The results indicate that the sample can serve as a suitable carrier for the ciprofloxacin drug.

Global warming, driven by scientific and technological progress and rising environmental pollution, has intensified the need for alternative renewable energy sources like hydrogen. This study focused on designing a hydrogen-hydrogen oxygen (HHO) cell using primary materials, where stainless steel electrodes (10 cm diameter) were coated with carbon nanotubes (CNTs) via electrochemical deposition. The CNTs were synthesized from potato peel waste, demonstrating an eco-friendly approach to nanomaterial production. Structural and morphological analyses of the CNTs were conducted using scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD), confirming their high surface area and crystalline structure. The research also investigated the impact of electrolyte concentration potassium hydroxide (KOH) on hydrogen production efficiency. By varying electrolyte parameters and applied current, the study monitored gas output per unit time, revealing a significant increase in H₂ and O₂ flow rates with CNT-coated electrodes. The enhanced performance was attributed to the electrodes' improved conductivity, corrosion resistance, and catalytic activity. These findings highlight the potential of nanotechnology in optimizing renewable energy systems, offering a sustainable solution for green hydrogen production.