Iraqi Journal of Physics

In this study, spin coating was used to prepare thin films of poly (2-
methoxy-5-(2-ethylhexyloxy)-1, 4-phenylene vinylene) and silver (MEH-PPV/Ag)
in this study. The physical characteristics of MEH-PPV/Ag thin films with various
weight ratios (0.01, 0.02, 0.03, and 0.04%) were investigated by Fourier-transform
infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction analysis (XRD), and
thermal testing. FTIR analysis showed that there were occurrences of the polymer's
predicted chemical bonds. AFM tests show that when different amounts of silver
are added to a polymer matrix, the film's surface roughness (root mean square)
goes up from an average of 83.51 to 511.3 nm. FE-SEM analysis showed that a
pure sample of the polymer formed evenly. However, when different amounts of
Ag were added, clear balls or circles formed, showing the energy of mixing
between the MEH-PPV and Ag. As silver addition transformed the polymer from
amorphous to polycrystalline, XRD analysis revealed both phases. In tests
comparing pure MEH-PPV to MEH-PPV/Ag, the polymer containing silver
showed higher thermal conductivity.

This study aims to investigate the aluminum (Al) arc plasma parameters
generated through the explosive strip technique. The research involves the
measurement of key plasma characteristics such as plasma frequency (fp), Debye
length, and Debye number. The electron temperature (Te) and electron density (ne)
of the plasma were calculated utilizing the Boltzmann plot and Stark expansion
method. Analysis of the optical emission spectrum revealed distinctive peaks
corresponding to oxygen, Al, and zinc oxide (ZnO) within the plasma. The
outcomes of the study demonstrated a noteworthy correlation between the applied
current and the electron temperature and density. Specifically, as the current
increases, both electron temperature and density increase. The electron temperature
of the Al plasma increased from the range of 0.852 eV to 0.92404 eV,
accompanied by a corresponding elevation in electron density from 13.1× 1017 cm-3
to 15.2× 1017 cm-3. Furthermore, the detonation of the Al strip within a ZnO
suspension led to even more pronounced changes. In this case, the electron
temperature surged from 0.92885 eV to 1.1012 eV, and the electron density
experienced an increase from 37.7 × 1017 cm-3 to 44.7 × 1017 cm-3.

In this paper, a cold plasma system utilizing a high voltage of 13.5 kV of
alternative (AC) and direct current (DC) was used under atmospheric pressure with
argon (Ar)-gas at a flow rate of 2.5 l/min and a flowing time of 4 min to synthesize
aluminum oxide (AlO) nanoparticles (NP). From the results, when DC was used, it
was found that the absorption spectrum starts at 303 nm and gradually falls to
870 nm. With AC, the absorption spectrum was at 330 nm and then began to fall to
902 nm. The energy gap when utilizing DC and AC was 3.49 and 3.44 eV
respectively. The analysis of the X-ray diffraction (XRD) patterns showed the
structure of the NPs was amorphous, matching the pattern 42-1746. At DC, the
average size of NPs formed, as deduced from the XRD pattern, was 29.56 nm, and
it was very close to what appeared in the field emission scanning electron
microscopy (FESEM) images, in which the apparent NP size ranged between 20
and 50 nm. The XRD test gave an average NP size of 38.21 nm in AC, while the
FESEM images showed a size range of 20-60 nm. At dc, the AlO NPs were
aggregated and interconnected, and each set was connected to another set, as
shown in the FESEM images. At AC, the shape of the synthesized AlO NPs was
quasi-spherical, with slightly elongated particles connected.

In the present work, optical emission spectroscopy was used to diagnose
the influence of A.C. power source frequency on the hollow magnetron sputtering
discharge parameters (such as discharge emission, discharge current and voltage,
glow discharge structure, temperature (Te) and electron number density (ne), Debye
length (λD), and plasma parameter (ND) of constant pressure. The electron
temperature and number density were determined using the Boltzmann plots and
the Stark broadening methods, respectively. The results illustrate that the normal
glow discharge structure is similar to the D.C. discharge mode. The magnetic field
has no impact on the fundamental discharge parameter in both A.C. frequencies
under study. On the other hand, the other discharge parameters (Te, ne, λD, and ND)
increase with increasing the magnetic field in both discharge frequencies. In
addition, the increase in the frequency of the A.C. source current led to an increase
in the discharge intensity emission and the other discharge parameters being
studied. In this case, in frequency 7 kHz, Te surged from 0.685 eV to 0.839 eV, and
n
e experienced an increase from 3.088 x 1018 m-3 to 4.902 x 1018 m-3. At a
frequency of 9 kHz, the electron temperature surged from 0.711eV to 0.911 eV. ne
experienced an increase from 3.615 x 1018 m-3 to 6.749 x 1018 m-3.

This study investigates polyacrylonitrile:hydroxypropyl methylcellulose
)PAN:HPMC( and PAN:HPMC: graphene (Gr) composite nanofibers prepared
using the electrospinning technique. Electrospinning is a simple and versatile
technique that relies on the electrostatic repulsion between surface charges to
continuously draw nanofibers from a viscoelastic fluid. Membrane technology is
vital in removing contaminants due to its easy handling and high efficiency. The
results demonstrated that the Gr was successfully incorporated into the
PAN:HPMC nanofiber membranes, as confirmed by scanning electron microscopy,
Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD)
measurements. The Gr content has a significant impact on the diameter, porosity,
and pore size. The PAN:HPMC:0.02Gr electrospun nanofiber membranes achieved
excellent oil rejection (72.47%) and good permeability flux (750 LMH); this might
be a result of how well the functional groups of the equally distributed Gr within
the PAN:HPMC nanofibers interacted with oil. It was noticed that oil rejection
dropped a lot as the Gr content went up. This is likely because the pores got wider
and some of the Gr stacked or agglomerated across the nanofibers.

Adaptive optics revolutionizes telescopic resolution but faces cost,
complexity, and calibration hurdles. Neural network adaptive optics (NNAO)
offers promise by using neural networks to tailor corrections to telescopes and
atmospheric conditions, by passing calibration and sensors. This MATLAB-based
study examines NNAO's impact on astronomical image quality, revealing it as a
cost-efficient solution that enhances adaptive optics in astronomy. The numerical
simulation results were encouraging, with a compensation rate exceeding 50% due
to favorable monitoring conditions. The results indicate that the dominant factor
affecting image quality is the variance of wavefront aberrations. The Strehl ratio
(SR) decreases from an average of 0.548 for a variance of 0.2 to 0.020 for a
variance of 0.6, while the mean squared error (MSE) increases from an average of
0.613 to 5.414. However, the effect on peak signal-to-noise ratio (PSNR) is
inconclusive. Furthermore, it was found that increasing the number of neurons and
training ratio does not significantly impact the results obtained, but it noticeably
affects the computational time required.

The growing need for unique optical properties in the manufacturing of
electronic devices has led the world to the field of hybrid materials and their
composites. In this study, a simple physical technique was used to successfully
manufacture hybrid nanocomposites containing nanoparticles of titanium dioxide
(TiO2) and reduced graphene oxide (rGO) from tetrabutyl titanate (TBT) and
graphene oxide (GO) powder using the hydrothermal method. For two
hydrothermal treatment times (12h and 24h), various samples were created: TiO2,
rGO, and TiO2/rGO nanocomposites thin films. Fourier transformer infrared
(FTIR) spectra of the samples gave clear evidence for the reduction of GO and the
engagement of Ti with reduced graphene by the formation of a Ti-O-C bond. The
measurement of the energy band gap obtained by the photoluminescence
spectrometer shows a decrease in the energy band gap for all samples after the
hydrothermal reaction time increases, for the composite, the band gap decreases to
2.65 eV and 2.64 eV.

In this work, using the spin coating method to create polyvinylidene
fluoride (PVDF)/polyethylene oxide (PEO) thin films, the effects of nano-tungsten
oxide (WO2) doping were investigated. The novelty of this research lies in its
investigation of varying weight concentrations of WO2 nanoparticles (NPs) within
the composite films. Comprehensive characterization techniques were employed,
including structural analysis via X-ray diffraction (XRD), which revealed a clear
and prominent peak in the XRD of the PVDF/PEO films, and the films'
polycrystalline nature with tetragonal structures. The grain size was noted to
increase with higher WO2 NPs doping. Field emission scanning electron
microscopy (FE-SEM) showed hexagonal-like α-phase PVDF crystals and uniform
distribution of WO2 NPs. Furthermore, Fourier-transform infrared spectroscopy
(FTIR) confirmed the characteristics of PVDF/PEO and identified specific doping
compounds, confirming successful incorporation. The optical transmittance spectra
unveiled the films' optical band gap energy, optical transition types, and absorption
characteristics, where novelty emerged as the band gap energy significantly
increased from 3.0 eV to 3.64 eV with an increased WO2 NPs weight doping
percentage, signifying profound electronic structure modifications and potential
applications in optoelectronics and sensors.

Nanocomposite membranes made of chitosan (Cs) concentrations, and
polyvinyl alcohol (PVA) with a fixed ratio of (60:40), then incorporated with
different concentrations of multi-walled carbon nanotubes (MWCNTs) (1, 1.5, 2,
2.5, and 3%) were created using the solution cast method. The membranes were
identified using UV-vis spectroscopy, Fourier transform infrared (FTIR), and Xray diffraction (XRD). The results demonstrated that the samples were sufficiently
stable, and the interactions between nanoparticles and polymers were generally
negligible. XRD patterns showed a crystalline phase of PVA, an amorphous phase
of chitosan, and a more crystalline phase as MWCNTs were introduced. In
particular, at high percentages of MWCNTs, the dominant phase (002), connected
to MWCNTs, was shifted to a higher value. The UV-vis spectroscopy of the
sample showed only one absorption peak at about 230 nm and no other peaks. This
may be due to transparency in PVA and Cs. The band gap energy decreased when
higher percentages of MWCNTs were added to the mixture.