Iraqi Journal of Physics

In this work, the effects of size, and temperature on the linear
and nonlinear optical properties in InGaN/GaN inverse parabolic
and triangular quantum wells (IPQW and ITQW) for different
concentrations at the well center were theoretically investigated.
The indium concentrations at the barriers were fixed to be always
xmax = 0.2. The energy levels and their associated wave functions
are computed within the effective mass approximation. The
expressions of optical properties are obtained analytically by using
the compact density-matrix approach. The linear, nonlinear, and
total absorption coefficients depending on the In concentrations at
the well center are investigated as a function of the incident photon
energy for different values of temperature and quantum wells size.
The results show that the In concentrations, size and temperature
have a significant effect on these optical properties. The positions
of the resonance peaks of the absorption coefficients were blueshifted under increasing indium compositions in the quantum wells
(InGaN) and temperature while they were red-shifted with the
increase in the thickness of the wells. Moreover, the amplitudes of
the resonance peaks were enhanced under the increase of the In
composition, the temperature, and the thickness of the quantum
wells. The optical absorption in ITQW structure is slightly greater
than that in IPQW one.

Polycaprolactone polymer is widely used in medical applications
due to its biocompatibility. Electro spinning was used to create poly
(ε- caprolactone) (PCL) nanocomposite fiber mats containing
hydroxyapatite (HA) at concentrations ranging from 0.05 to 0.4% wt.
The chemical properties of the fabricated bio composite fibers were
evaluated using FTIR and morphologically using field-emission
scanning-electron microscopy (FESEM), Porosity, contact angle, as
well as mechanical testing(Young Modulus and Tensile strength) of
the nanofibers were also studied. The FTIR results showed that all the
bonds appeared for the pure PCL fiber and the PCL/HA nano fibers.
The FESEM nano fiber showed that the fiber diameter increased from
54.13 to 155.79 (nm) at the HA values from (0.05 % and 1%wt.).
Porosity, wettability of (PCL/HA) composites has improved, and the
contact angle has decreased from 103.59o to 85.57o for fibrous
scaffolds. The inclusion of hydroxyapatite increased the tensile
strength of nano fiber scaffolds, and the maximum tensile strength of
0.4% percent was about 0.127 MPa, with a lowering in elongation to
40%.

In this work, the effect of preparing a composite of copper oxide
nanoparticles with carbon on some of its optical properties was
studied. The composite preparing process was carried out by
exploding graphite electrodes in an aqueous suspension of copper
oxide. The properties of the plasma which is formed during the
explosion were studied using emission spectroscopy in order to
determine the most important elements that are present in the media.
The electron’s density and their energy, which is the main factor in the
composite process, were determined. The particle properties were
studied before and after the exploding process. The XRD showed an
additional peak in the copper oxides pattern corresponding to the
hexagonal graphite structure for the composite. The UV-visible
absorbance for the composite was significantly enhanced. The direct
bandgap decreased from 2.55 to 2.4 eV, and the indirect bandgap
decreased from 1.1 to 1 eV, for the composite.

The paper presents an overview of theoretical aspects of small
radio telescope antenna parameters. The basic parameters include
antenna beamwidth, antenna gain, aperture efficiency, and antenna
temperature. These parameters should be carefully studied since they
have vital effects on astronomical radio observations. The simulations
of antenna parameters were carried out to assess the capability and the
efficiency of small radio telescopes to observe a point source at a
specific frequency. Two-dimensional numerical simulations of a
uniform circular aperture antenna are implemented at different radii.
The small diameter values are chosen to be varied between (1-10) m.
This study focuses on a small radio telescope with a diameter of 3 m
since this telescope is very common in the world. The simulated results
of this study illustrated that the power pattern of a 3 m antenna has a
half-power beamwidth of approximately 5 degrees. Also, the
maximum peak antenna temperature is estimated to be more than 3000
K. All of these results were in good agreement with observations of
the neutral hydrogen spectral line at the frequency of 1.42 GHz using
a small radio telescope.

An oxidative polymerization approach was used to create
polyaniline (PANI) and Fe2O3 /PANI nanoparticle combination.
Various characterization approaches were used to investigate the
structural, morphological, and Fe2O3 /PANI nanoparticle structures.
The findings support the synthesis of polycrystalline nanoparticle
PANI and Fe2O3 /PANI spherical nanoparticle composites. Grampositive bacteria are tested for antibacterial activity. Various quantities
of Nanoparticles of PANI and Fe2O3 /PANI nanoparticle composites
were used to test Staph-aureus and gram-negative bacteria, E-coli, and
candida species. PANI has antibacterial properties against all
microorganisms tested. Fe2O3 /PANI nanoparticle composites, on the
other hand, have higher antibacterial activity, as evidenced by the zone
of inhibition. Bacterial inhibition zones are in S. aureus (positive), and
E. coli are in good functioning order. With increasing concentrations
of Fe2O3 /PANI nanoparticle composites, the inhibition zones of all
bacteria are larger. Finally, the antimicrobial activity of Fe2O3 /PANI
nanoparticle composite is characterized using a simplified mechanism
based on electrostatic attraction. In this paper, a conductive polymer
doped with iron nanoparticles was fabricated for the aim of testing it
in the field of bacterial resistance.

Ultraviolet light radiation is applied to treat Plaque Psoriasis
disease by targeted phototherapy. This is available through
Narrowband-UVB light radiation devices peaked at wavelength 311
nm. Ten cases were chosen as a study group, 8 males aged 22-40 years
old, and 2 females aged 25 and 32 years old who were exposed to
ultraviolet light radiation. Their recovery or improvement was
followed weekly. Different doses were used according to the severity
of the lesion and as a trial for the outcome. The dose was given two
times a week, starting with 200mJ/cm2, and subsequently increased by
100 or 200 mJ/cm2 reaching a maximum dose as tolerated by each
individual patient. Improvement was observed after 4 – 6 weeks. The
patient stays in the treatment cabinet for a few seconds to several
minutes according to the individual case which depends on the area of
the body being treated. Treatment was stopped for two patients due to
in toleration to the recommended dose. It was observed that good
treatment results were obtained for the other 8 patients. The recovery
rate from the disease was in the range of 50-100%. This is depending
on the duration of the occurrence of the disease and the reduction of
the size of the affected area on the skin for each individual patient after
treatment.

Cadmium oxide (CdO) thin films were deposited using the
sequencing ion layer adsorption and reaction (SILAR) method. In this
study, the effect of the pH value of an aqueous solution of cadmium
acetate at a concentration of 0.2 mol of the cadmium oxide film was
determined. The solution source for the cadmium oxide film was
cadmium ions and an aqueous ammonia solution. The CdO films were
deposited on glass substrates at a temperature of 90 ℃. The cadmium
oxide film thickness was determined by the weight difference method
at pH values (7.2, 8.2). X-ray diffraction (XRD) and scanning electron
microscopy (SEM) showed that the size of the crystals increased with
the increase in the solution (pH). While the UV-visible spectra of the
films revealed that the optical band gap energy decreases with
increasing (pH) of the CdO solution. The absorbance spectrum of the
cadmium oxide film was recorded in the wavelength range (300 – 900)
nm. The change in the pH of the cadmium acetate aqueous solution
from the energy gap and X-ray diffraction calculations showed that the
film had an optical band gap energy and that the highest intensity was
at (111) and that the membrane is n-type, as shown by studies to
prepare the cadmium oxide membrane using the SILAR method.

In current research Copper was employed for preparing a ternary
system of Al–Si alloy in different (0.2–2.5 wt. %) the best was taken
is (1.5%wt) of copper that circumstances of solidification for
improving the mechanical performance of the available in aluminium
alloy. Cast iron molds were prepared to obtain tensile strength testing
specimens. Alloys were prepared by employing gas furnaces. The
molten metal was poured into a preheated cast-iron mold. The
obtained alloy structures were studied using an X-ray diffractometer
and optical microscopy. The mechanical performance of the prepared
alloys was examined under the influence of different hardening
conditions in both heat and non-heat-treated conditions. The outcomes
showed at the ideal input status of friction stir processing, the cast alloy
microstructure was enhanced in terms of refinement of eutectic and
primary Si particles, homogeneous dispersion of Si, and the reduction
in porosity. The mineral compounds formed during the hardening
process were examined using an optical microscope. The highest
maximum tensile strength (UTS) was 120 MPa for sample Al-22.5Si,
and 147 MPa for sample Al-21Si-1.5Cu, while the highest hardness
was 77 HB for sample Al-22.5Si, and 90 HB for sample Al-21Si-
1.5Cu.

Carbon nanoparticles are prepared by sonication using carbon
black powder. The surface morphology of carbon black (CB) and
carbon nanoparticles (CNPs) is investigated using scanning electron
microscopy (SEM). The particles size ranges from 100 nm to 400 nm
for CB and from 10 nm to 100 nm for CNPs. CNPs and CB are mixed
with silicon glue of different ratios of 0.025, 0.2, 0.05, and 0.1 to
synthesis films. The optical properties of the prepared films are
investigated through reflectance and absorbance analyses. The ratio of
0.05 for CNPs and CB is the best for solar paint because of its higher
solar water heater efficiency and is then added to the silicon glue. The
temperature of cold water and temperature of hot water in the storage
tank were tabulated on hourly basis with the help of an Arduino device.
The atmospheric temperature was also noted. It was observed that the
outlet temperature of the water was attained up to 75°C as compared
to the inlet water temperature of 23°C for the tank applied with CNPbased paint. The tank applied with CNP-based paint has 4 °C higher
water temperature than that coated with CB-based paint after 1 month
of the test under sun irradiation. Based on the results, the efficiency of
a solar water heater depends on the difference in temperature of inlet
water and outlet of heater. The efficiency of the solar water heater
coated with CNPs is around 77% but the solar water heater coated with
CB has an efficiency of 67%.