Iraqi Journal of Physics

In this study, nanocomposites have been prepared by adding
multiwall carbon nanotubes (MWCNTs) with weight ratios (0, 2, 3,
4, 5) wt% to epoxy resin. The samples were prepared by hand lay-up
method. Influence of an applied load before and after immersion in
sodium hydroxide (NaOH) of normality (0.3N) for (15 days) at
laboratory temperature on wear rate of Ep/MWCNTs
nanocomposites was studied. The results showed that wear rate
increases with increasing the applied load for the as prepared and
immersed samples and after immersion. It was also found that epoxy
resin reinforced with MWCNTs has wear rate less than neat epoxy.
The sample (Ep + 5wt% of MWCNTs) has lower wear rate. The
immersion effect in base solution led to increase in wear rate values
for all samples compared to natural condition.

In this work, copper substituted cobalt ferrite nanoparticles with
chemical formula Co1-xCuxFe2O4 (x=0, 0.3, and 0.7), has been
synthesized via hydrothermal preparation method. The structure of
the prepared materials was characterized by X-ray diffraction (XRD).
The (XRD) patterns showed single phase spinel ferrite structure.
Average crystallite size (D), lattice constant (a), and crystal density
(dx) have been calculated from the most intense peak (311).
Comparative standardization also performed using smaller average
particle size (D) on the XRD patterns of as-prepared ferrite samples
in order to select most convenient hydrothermal synthesis conditions
to get ferrite materials with smallest average particle size.

The pure ZnS and ZnS-Gr nanocomposite have been prepared
successfully by a novel method using chemical co-precipitation. Also
conductive polymer PPy nanotubes and ZnS-PPy nanocomposite
have been synthesized successfully by chemical route. The effect of
graphene on the characterization of ZnS has been investigated. X-ray
diffraction (XRD) study confirmed the formation of cubic and
hexagonal structure of ZnS-Gr. Dc-conductivity proves that ZnS and
ZnS-Gr have semiconductor behavior. The SEM proved that
formation of PPy nanotubes and the Gr nanosheet. The sensing
properties of ZnS-PPy/ZnS-Gr for NO2 gas was investigated as a
function of operating temperature and time under optimal condition.
The sensitivity, response time and recovery time were calculated
with different operating temperatures.

Nonlinear diffraction pattern can be induced by focusing CW
laser into a thin quartzes cuvette containing nanofluid. The number
of revealed pattern rings indicates to the nonlinear behavior of fluid.
Here, the nonlinear refractive index of each of functionalized single
wall carbon nanotube (F-SWCNTs) suspention and multi wall carbon
nanotube (F-MWCNTs) suspention have been investigated
experimentally .Each of CNTs suspention was at volume fraction of
13×10−5 and 6×10−5. Moreover the laser source at wavelength of
473 nm was used. The results show that SWCNTs suspention
possesses higher nonlinearty than other at the same volume fraction.

Radiation measuring devices need to periodic calibration process
to examine their sensitivity and the extent of the response. This study
is used to evaluate the radiation doses of the workers in the
laboratories of the Directorate of Safety as a result of the use of point
sources in calibrating of the devices in two ways, the first is the
direct measurement by the FAG device and the others using
RESRAD and RAD PRO programs. The total doses values using
FAG were (2.57 µSv/y, 102.3 µSv/y and 20.75 µSv/y for TLD
laboratory, Gamma spectroscopy analyses (GSA) laboratory and
equipment store respectively, and the total doses that calculated using
RESRAD and RAD PRO were 1.518 µSv/y, 76.65 µSv/y and
21.2 µSv/y for the above laboratories. the dose rate is very low
compare with the national, international dose rate limits (20 mSv/y).

Diamond-like carbon (DLC) homogeneous thin films were
deposited from cyclohexane (C6H12) liquid by using a plasma jet
system which operates with alternating high voltage 7.5 kv and
frequency 28 kHz. The optical and structural properties and chemical
bonding of these films were investigated. In this work, the effect of
changing the distance between the substrate and the plasma torch (2,
2.5 and 3 cm) was studied. The flow rate of argon gas which used to
generate the plasma was fixed (0.5 L/min). These films were
characterized by UV–Visible spectrophotometer, X-ray
diffractometer (XRD) and scanning electron microscopy (SEM) and
Fourier transformation infrared spectroscopy (FTIR). The maximum
absorption (λmax) appears around 312, 298.3 and 293.2 nm at the three
distance between plasma torch and the substrate 2.5, 2 and 3 cm,
respectively. The values of the optical energy gap are 3.47, 3.65 and
3.76 eV at a different distance (2, 2.5 and 3cm), respectively. In XRD
diffraction pattern, The occurrence of diamond peaks and graphite
peaks in the x-ray spectrum for these films Indicates that there is an
occurrence of local ordered sp3 and sp2 for carbon domains and
graphite respectively.

Aluminum plasma was generated by the irradiation of the target
with Nd: YAG laser operated at a wavelength of 1064 nm. The
effect of laser power density and the working pressure on spectral
lines generating by laser ablation, were detected by using optical
spectroscopy. The electron density was measured using the Stark
broadening of aluminum lines and the electron temperature by
Boltzmann plot method it is one of the methods that are used. The
electron temperature Te, electron density ne, plasma frequency
and Debye length increased with increasing the laser peak
power. The electron temperature decrease with increasing gas
pressure.

Optical properties of Rhodamine-B thin film prepared by PLD
technique have been investigated. The absorption spectra using
1064nm and 532 nm laser wavelength of different laser pulse
energies shows that all the curves contain two bands, B band and Q
bands with two branches, Q1 and Q2 band and a small shift in the
peaks location toward the long wavelength with increasing laser
energy. FTIR patterns for Rhodamine-B powder and thin film within
shows that the identified peaks were located in the standard values
that done in the previous researches. X-ray diffraction patterns of
powder and prepared Rhodamine-B thin film was display that the
powder has polycrystalline of tetragonal structure, while the thin film
has an amorphous structure. SEM images for Rhodamine-B, shows
homogeneous distributed cauliflower-like nanostructures attached
with each other. FM diagram shows that the average grain size was
found to be 68.52 nm and the RMS surface roughness was 1.68 nm.

In this study, pure Co3O4 nano structure and doping with 4 %, and
6 % of Yttrium is successfully synthesized by hydrothermal method.
The XRD examination, optical, electrical and photo sensing
properties have been studied for pure and doped Co3O4 thin films.
The X-ray diffraction (XRD) analysis shows that all films are
polycrystalline in nature, having cubic structure.
The optical properties indication that the optical energy gap follows
allowed direct electronic transition calculated using Tauc equation
and it increases for doped Co3O4. The photo sensing properties of
thin films are studied as a function of time at different wavelengths to
find the sensitivity for these lights.
High photo sensitivity doped Co3O4 with 6% of Yttrium, is a
118.774% at wavelength 620 nm, while for pure Co3O4 films no
sensitivity at the same wavelength. So, higher sensitivity is found for
doping Co3O4 with fast rise and fall times less than 1s.

A statistical optical potential has been used to analyze and
evaluate the neutron interaction with heavy nuclei 197Au at the
neutron energy range (1-20 MeV). Empirical formulae of the optical
potentials parameters are predicted by using ABAREX Code with
minimize accuracy compared with experimental bench work data.
The total elastic, absorption, shape elastic and total compound crosssections are calculated for different target nuclei and different
incident neutron energies to predict the appropriate optical
parameters that suit the present interaction. Also the dispersion
relation linking between real and imaginary potential is analyzed
with more accuracy. The results indicate the behavior of the
dispersion contribution in imaginary potential has a parabolic change
about the Fermi surface energy while in the real potential it fall with
increasing the neutron energy. Good agreements have been achieved
with the available experimental data.

Pure and Fe-doped zinc oxide nanocrystalline films were prepared
via a sol–gel method using -C for 2 h.The thin films were prepared and characterized by X-ray diffraction(XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM) and UV- visible spectroscopy. The XRD results showed that ZnO has hexagonal wurtzite structure and the Fe ions were well incorporated into the ZnO structure. As the Fe level increased from 2 wt% to 8 wt%, the crystallite size reduced in
comparison with the pure ZnO. The transmittance spectra were then
recorded at wavelengths ranging from 300 nm to 1000 nm. The optical band gap energy of spin-coated films also decreased as Fe doping concentration increased. In particular, their optical band gap energies were 3.75, 3.6, 3.5, 3.45 and 3.3 eV doping concentration of 0%, 2%, 4%, 6% and 8% Fe, respectively. The performance of the pure and doped ZnO thin films was examined for the photocatalytic activity using organic dyes (methyl orange, methyl blue, methyl violet). The samples ZnO with concentration of Fe showed increased photocatalytic activity with an optimal maximum performance at 0.8 wt%

Rare earth elements (Cerium, Lanthanum and Neodymium) doped
CdS thin films are prepared using the chemical Spray Pyrolysis
Method with temperature 200 oC. The X-ray diffraction (XRD)
analysis refers that pure CdS and CdS:Ce, CdS:La and CdS:Nd thin
films showed the hexagonal crystalline phase. The crystallite size
determined by the Debye-Scherrer equation and the range was (35.8–
23.76 nm), and it was confirmed by field emission scanning electron
microscopy (FE-SEM). The pure and doped CdS shows a direct band
gap (2.57 to 2.72 eV), which was obtained by transmittance. The
room-temperature photoluminescence of pure and doped CdS shows
large peak at 431 nm, and two small peaks at (530 and 610 nm). The
Current – voltage measurement in dark and illumination
(100 mW/cm2, 183 mW/cm2 and 288 mW/cm2) condition. The
photocurrent increases and the resistivity decreases with the light
intensity increases. So film reveals photoconductivity phenomena
suggesting it's useful for optoelectronic applications.

Polyacrylamide Solutions of different concentrations (0.2, 0.4,
0.6, 0.8, 1.0 %) of Ag nanoparticles and ZnO nanoparticles were
prepared, the viscosities and surface tension were measured for all
solutions, where measurements indicated an increase in these
properties with increased concentration, where the relative viscosity
of polyacrylamide/zinc nanoparticles increased from 1.275 to 2.243,
and the relative viscosity of polyacrylamide/silver nanoparticles
increased from 1.178 to 1.934. Viscosity is significant parameters
during electrospinning process. While the surface tension of the
polyacrylamide/zinc nanoparticles has changed from 0.0343 Nm-1 to
.0.0.0 Nm-1 and changed from .0.000Nm-1 to.0.0.0 Nm-1. Also
the constants KH and KK were calculated from the slopes of viscosity
figures related to equations of Huggins and Kramer. These results
can be used in medical, industrial applications and Scientific studies.

In this study, phosphorescence analysis (KPA) is used for
determining soil collected from the Tigris River from Al- Karrada
and Bab Al-Sharq in Baghdad and samples were taken from
rainwater collected from Al-Rashad, Al-Obeidi, Al-Dora and Al-Sadr
City in Baghdad. The measurements were carried out by the Iraqi
Ministry of Health and Environment, in the Radiation Protection
Center. The collection, removal and evaporation of the samples
ranged from January to the end of March 2018. The results show the
presents of concentration of 238U and 235U in soil samples and the
rainwater samples. The conclusion of this work is the concentration
of uranium in soil samples is more than recommendations by ICRP
value of 1.9 μg /l. While all water samples can be compared with the
value of WHO, which has a safe limit of 15 μg/l which is considered
acceptable.

This work investigates the utilization of waste papers (natural and
industrial) i.e (citrus aurantium and papers A4) mortars containing
specified contents 0.5%, 1%, 1.5% of waste papers were prepared
and cured. Mechanical characteristics such as compressive and
bending strengths, hardness and water absorption were determined
for the mortars mixed with the waste papers and compared with those
obtained from the pure mortars. Results showed that the addition of
waste paper leads to increase the hardness to (69 - 68.5) shore D for
(natural and industrial) wastes materials respectively comparing with
pure specimen 66 shore D. The compressed strength of the mortar
cement specimen cured for 28 days from 13 MPa to (17-18) MPa for
(natural and industrial) wastes materials, respectively.