Iraqi Journal of Physics

Lead and concrete blocks are well known for shielding against ionizing radiation, but
their use is limited due to their high density, toxicity, and environmental concerns.
This study investigates the potential of Bambusa vulgaris (bamboo powder)-based
mortar composites as an alternative gamma-ray radiation-shielding material. Different
blends of bamboo powder, sand, and cement were chemically treated to produce
binary and ternary composites. The elemental composition of Bambusa vulgaris was
determined using X-ray fluorescence (XRF), while the radiation attenuation
coefficients of the samples against rays were determined using a NaI(Tl) scintillation
detector and Cs-137 gamma source (662 keV). Key shielding parameters, including
Linear and Mass Attenuation Coefficients (LACs and MACs), Half-Value Layer
(HVL), Tenth-Value Layers (TVLs), Mean Free Paths (MFPs), and compressive
stress, were determined. The composite containing 57.14% bamboo, 28.57% sand,
and 14.29% cement exhibited the most superior attenuation properties with LAC,
MAC, HVL, TVL, MFP, and stress of 1.015 cm⁻¹, 1.067 cm²/g, 0.683 cm, 2.269 cm,
0.985 cm, and 0.620 kPa, respectively. The composite exhibits radiation attenuation
capability but a lower mechanical strength. Thus, bamboo-based mortar may be
explored for applications requiring gamma radiation protection

This work presents a numerical study of a multilayer optical biosensor based on
distributed Bragg reflectors (DBRs) with a blood-filled cavity. The Transfer Matrix
Method (TMM) was employed and simulated in MATLAB to analyze the resonant
behavior over the wavelength range 780-810 nm. The analysis also considered the
effects of temperature variation from 15 to 40 °C and changes in the silicon layer
thickness from 20 to 200 nm. The results revealed a blue shift in the resonant
wavelengths of the defect mode due to temperature variation, leading to a negative
thermal sensitivity whose magnitude depends nonlinearly on the silicon layer
thickness. In addition, electric field intensity distributions at resonance revealed
stronger localization of the mode within the cavity for intermediate silicon layer
thicknesses. This increases the interaction between light and matter and broadens
the spectral shift range induced by temperature changes. Conversely, thick silicon
layers redistribute optical energy in the Bragg mirrors, compensating for thermal
drift with partial compensation occurring due to redistribution. The results show
that the performance of resonance confinement and temperature response can be
significantly enhanced through geometric tuning, demonstrating the potential
application of this design as an optical biosensor for malaria-related blood
diagnostics without requiring labels.

This work presents the fabrication of highly efficient gas sensors based on silver
oxide (AgO)- doped cadmium sulfide (CdS) nanostructures deposited on porous
silicon (PS) substrates using pulsed laser deposition (PLD). Three doping
concentrations of AgO (5, 10, and 15%) were investigated to evaluate their
influence on the structural, optical, and gas sensing properties of CdS. The prepared
films were characterized using X-ray diffraction (XRD), field emission scanning
electron microscopy (FESEM), atomic force microscopy (AFM), UV–Vis
spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The XRD
results confirmed enhanced crystallinity with increasing AgO concentrations, while
FESEM and AFM analyses revealed a nanostructured surface with increased
roughness and active surface area. UV–Vis measurements showed a reduction in
the optical band gap upon AgO incorporation, whereas FTIR spectra confirmed the
successful formation of AgO:CdS heterostructures. Gas-sensing measurements
demonstrated that the CdS with 5% AgO sensor exhibited the highest NO₂ sensing
response of 92.8% at an operating temperature of 100°C. The enhanced sensing
performance is attributed to the synergistic effect of AgO/CdS heterostructure
formation, increased adsorption sites, and improved charge transfer through the PS
substrate. The developed AgO:CdS/PS platform offers tunable sensing behavior by
controlling dopant concentration and operating temperature, making it a promising
candidate for high-performance toxic gas sensing applications.

Positron emission tomography (PET) using ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) is
a cornerstone in oncological imaging for tumor localization and therapeutic
assessment. Despite its diagnostic utility, limited attention has been given to its
transient effects on hematological parameters. This study evaluates hematologic
and immunological alterations following FDG administration by analyzing
changes in red blood cells (RBCs), white blood cells (WBCs), and platelets before
and after injection. The experimental cohort included one healthy subject and
three cancer patients (liver, breast, and uterine). Peripheral blood samples were
obtained pre- and post-FDG injection, with subsequent blood film analysis
assessing RBC aggregation, WBC distribution, platelet morphology, and
indicators of blood viscosity. Findings revealed reversible hematological
changes, notably increased RBC aggregation, suggesting transient hyper
viscosity potentially driven by oxidative stress. Differential leukocyte analysis
revealed neutrophilia, lymphopenia, and monocytosis, suggesting immune
modulation. Additionally, a mild rise in platelet aggregation suggested a
temporary prothrombotic state. The study concludes that FDG-PET elicits shortterm
hematological and immunological shifts. These outcomes highlight the
importance of cautious interpretation of PET findings in oncology settings and
emphasize the need for further investigations into oxidative and
immunomodulatory effects to enhance patient safety and diagnostic accuracy.

Metal-Organic Frameworks (MOFs) are essential in nanotechnology applications
due to their unique properties. MOFs can be easily tailored for specific uses by
altering the metals or organic linkers involved, such as zirconium-based metalorganic
frameworks (Zr-MOFs). Among the several methods used to create
nanoscale Zr-MOFs are microwave-assisted synthesis, solvothermal, sonochemical,
ionothermal, and mechanochemical procedures. The synthesis, structure, and
characterization of Zr-MOFs were compared in this project between conventional
solvothermal and microwave-assisted methods for nitrogen adsorption/desorption.
Using X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy
(FTIR), and thermogravimetric analysis (TGA), the two processes for synthesizing
Zr-MOFs were characterized. The outcomes demonstrate the crystalline structure of
both MOFs. The key benefits of microwave-assisted synthesis over other methods
are its quick nucleation rate, short reaction time, and improved Zr-MOF
characteristics. Furthermore, the microwave-assisted method significantly
accelerated the synthesis process, achieving complete reaction within 10 minutes at
120 °C, whereas the conventional process typically takes 24 hrs. The results revealed
that nitrogen adsorption/desorption by Zr-MOF microwave-assisted synthesis is
more dominant than the conventional solvothermal synthesis technique.

In this study, chitosan/polyvinyl alcohol (CS/PVA) films were prepared with
different weight ratios (98:2, 96:4, 94:6, 92:8, and 90:10%) using the solution
casting method to study the structural, thermal, and tensile strength properties of
the composites. The Fourier transform infrared (FTIR) spectroscopy of CS/PVA
samples showed some differences, such as changes in the strength, location, and
intensity of the CO and CH2 stretching bands. The differential scanning
calorimetry (DSC) revealed that the incorporation of PVA enhanced the thermal
stability of the composites, with the 98:2wt.% blending the highest melting
temperature (Tm) at 289°C. The thermogravimetric analysis (TGA) further
confirmed improved thermal stability, showing a significant shift in the
decomposition peak toward higher temperatures and reduced mass loss within the
degradation zone (approximately 40 wt.% loss between 250 and 400°C).
Mechanically, the CS/PVA 98/2 wt.% blend demonstrated optimal performance,
achieving a tensile strength of 54.94 MPa, an elongation at break of 3.93%, and
a Young's modulus of 1.48 GPa. Scanning electron microscopy (SEM) showed a
highly homogeneous distribution of PVA within the chitosan at this specific ratio,
directly correlating with the superior tensile strength and enhanced flexibility of
the composite.

In this study, polyvinylpyrrolidone (PVP) fibers were fabricated using
electrospinning, and their properties were enhanced through dual doping with zinc
(Zn) and tin (Sn) ions at different Zn: Sn mixing ratios. The structural, optical, and
electrical characteristics of the fibers were investigated to evaluate their potential for
photodetector applications. The X-ray diffraction (XRD) analysis of pure PVP fibers
indicates an amorphous nature, whereas two broad diffraction peaks emerge after
mixing with ions, which is caused by the rearrangement of PVP chains due to their
interactions with the added ions. Field emission scanning electron microscope
(FESEM) images show a significant reduction in fiber diameters and an increase in
the density of the prepared fabric with an increase in the metal ion dopant. Fourier
transform Infrared (FTIR) analysis revealed shifts and intensity changes in
characteristic peaks and the appearance of metal oxide bands, indicating interactions
between the polymer matrix and the dopant ions, that contributing to the enhanced
functional properties. Incorporating Zn and Sn ions significantly improved the
photodetector performance of PVP fiber/n-Si devices. The doping with the two ions
significantly enhanced the photocurrent to 12.5 times compared to 2.5 times in the
pure PVP fiber/n-Si sample. The fabricated photodetector fibers at a 3:7 metal ion to
PVP ratio show a maximum photosensitivity of 24.8% under a violet light source. The
results from this study demonstrate the potential of dual Zn and Sn ion-doped PVP
fibers as efficient, low-cost, and flexible materials for photodetector applications to
violet light.

A comprehensive theoretical framework is developed to evaluate the anisotropic
coherence length in high-temperature superconductors based on the fluctuationinduced
conductivity approach. The theoretical model is formulated using wellestablished
expressions derived from the anisotropic Ginzburg-Landau theory,
incorporating both Aslamazov-Larkin and Maki-Thompson contributions.
Numerical calculations are carried out for two representative superconducting
systems, namely nano-(Co0.5Zn0.5Fe2O4)x/(Cu,Tl)-1223 and the Cd-doped (Cu,Tl)-
1234 phase, which exhibit distinct dimensional characteristics. The reduced
paraconductivity is analyzed as a function of reduced temperature, and the extracted
parameters are compared with previously reported experimental data. The results
demonstrate a good agreement between theoretical predictions and experimental
observations, confirming the validity and applicability of the proposed model.
Furthermore, the analysis highlights the strong influence of dimensionality and
interlayer coupling on the anisotropic coherence length. The proposed approach
provides a simple and reliable method for estimating superconducting parameters,
which can be useful for both fundamental studies and technological applications of
high-Tc superconductors.

Light atoms, such as oxygen, are treated with the 6-311G** basis sets, and heavy
atoms, like tin (Sn), are treated with SDD (Stuttgart/Dresden) basis sets. A density
functional theory (DFT) with a B3LYP hybrid functional calculation needs to be
done to work out the geometrical and electronic properties, such as the highest
occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital
(LUMO), and the energy gap, as well as the thermodynamic properties, such as
Gibbs free energy, enthalpy, entropy, and heat capacity of the tin dioxide (SnO₂)
pyramid nanocluster structure as a function of the number of oxygen atoms. These
theoretical calculations were performed using Gaussian 09W, while the geometry
was visualized using Gaussian View 05. It was found that the SnO₂ pyramid
nanocluster energy gap in the beginning increased with the increase of the oxygen
atoms and reached a maximum at Sn₁₀O₁₆, then dropped to a minimum value at 2.55
eV for Sn₁₀O₁₇. The Gibbs free energy and enthalpy values became more negative,
indicating that the reaction was exergonic.

The effect of active-layer thickness on PM6:Y6 organic solar cells' performance was
studied using several characterization techniques, such as current density vs. voltage
(J-V), capacitance vs. voltage (C-V), charge vs. voltage (Q-V), charge extraction by
linearly increasing voltage (CELIV), and sun-dependent. Results show that
increasing thickness increased light absorption and therefore short-circuit current
density (JSC), but excessive thickness caused transport limitations and higher
recombination, resulting in reduced fill factor (FF). On the other hand, open-circuit
voltage (VOC) remained weakly dependent on thickness variation. As a result, power
conversion efficiency (PCE) has initially increased and then declined beyond the
optimum thickness. C-V and Q-V results indicated reduced charge extraction
efficiency and increased series resistance in thick films. Recombination and mobility
analyses showed higher loss rates and lower effective mobilities with increasing
thickness, consistent with longer transport paths. CELIV confirmed more dispersive,
trap-limited transport in thicker layers. Light-intensity-dependent JSC followed a
near-linear dependence (α ≈ 1), and Suns-VOC measurements demonstrated
thickness-insensitive voltage governed mainly by recombination kinetics.

This study investigates the photoluminescence properties of lead iodide
(PbI₂) nanoparticles embedded in a polyvinyl alcohol (PVA) matrix when
illuminated by ultraviolet (UV) light. The PbI₂ nanoparticles, dispersed uniformly
within the PVA polymer matrix, exhibit enhanced stability and efficient light
emission due to the protective environment provided by PVA. Upon UV
illumination, the PbI₂ nanoparticles generate visible light, with emission
characteristics influenced by the nanoparticle size, concentration, and interaction
with the PVA matrix. The role of PVA as a stabilizing agent and its effect on the
photophysical properties of PbI₂ are analyzed, showing an improvement in quantum
efficiency and photostability. This hybrid nanocomposite system demonstrates
potential applications in UV-responsive optoelectronic devices, flexible lightemitting
materials, and photonic sensors. The study offers ideas about the integration
of semiconductor nanoparticles with polymer matrices for advanced light-generation
technologies. This study explores the interaction between UV light and
PbI₂ nanoparticles, focusing on the photophysical processes that lead to light
generation.

This study examines two distinct methods for preparing zinc oxide nanoparticles (ZnO
NPs) the chemical method and the green method. In the chemical method, zinc acetate and
deionized water were used, whereas in the green method, the plant extract from Capparis
spinosa fruit was used. The ZnO nanoparticles were analyzed using X-ray diffraction
(XRD), energy-dispersive X-ray spectroscopy (EDS), field-emission scanning electron
microscopy (FESEM), and Fourier transform infrared spectroscopy (FTIR). ZnO
nanoparticles prepared by chemical precipitation and biological methods were
characterized using UV-Vis spectroscopy to analyze the absorption spectra. The FESEM
images revealed the spherical shape of the nanoparticles. The sizes of the nanoparticles
were experimentally calculated using XRD and FESEM. The particle size measured by the
XRD pattern was 26 nm for the chemically synthesized ZnO NPs sample and 6 nm for the
ZnO NPs sample prepared by green synthesis. FTIR spectra showed that the stabilizing
agent made the particle surface inert. The results indicate that the ZnO NPs sample
synthesized using the green method is better than the chemically synthesized samples. This
comparative study highlights the influence of the capping agent and the resulting
morphologies on surface area and recombination kinetics, while also noting that it can be
used in medical applications due to its environmentally friendly method.