Iraqi Journal of Physics

Because of the quick growth of electrical instruments used in noxious gas detection, the importance of gas sensors has increased. X-ray diffraction (XRD) can be used to examine the crystal phase structure of sensing materials, which affects the properties of gas sensing. This contributes to the study of the effect of electrochemical synthesis of titanium dioxide (TiO2) materials with various crystal phase shapes, such as rutile TiO2 (R-TiO2NTs) and anatase TiO2 (A-TiO2NTs). In this work, we have studied the effect of voltage on preparing TiO2 nanotube arrays via the anodization technique for gas sensor applications. The results acquired from XRD, energy dispersion spectroscopy (EDX), and field emission scanning electron microscopy (FE-SEM) elucidate that TiO2 was created. In addition, systematically examining the gas detection properties was also done. The gas sensor was produced from TiO2 nanotubes, and the gas-detecting features were directed at nitrogen dioxide (NO2), which is a hazardous gas. The sensor formed from TiO2 nanotubes detects NO2 gas at various temperatures, from room temperature to 300 oC, and it has good sensitivity to this gas. The results exhibit that the gas sensor that was synthesized at 30 V has good sensitivity and a short response time at room temperature for NO2 gas sensing.

The current study used extracts from the aloe vera (AV) plant and the hibiscus sabdariffa flower to make Ag-ZnO nanoparticles (NPs) and Ag-ZnO nanocomposites (NCs). Ag/ZnO NCs were compared to Ag NPs and ZnO NPs. They exhibited unique properties against bacteria and fungi that aren't present in either of the individual parts. The Ag-ZnO NCs from AV showed the best performance against E. coli, with an inhibition zone of up to 27 mm, compared to the other samples. The maximum absorbance peaks were observed at 431 nm and 410 nm for Ag NPs, at 374 nm and 377 nm for ZnO NPs and at 384 nm and 391 nm for Ag-ZnO NCs using AV leaf extract and hibiscus sabdariffa flower extract, respectively. Using field emission-scanning electron microscopes (FE-SEM), the green synthesis of the shown NPs and NCs was found. The Ag NPs particle sizes ranged from 16.99 to 26.39 nm for AV and from 13.11 to 29.50 nm for hibiscus sabdariffa flowers, respectively. The particle size of ZnO NPs ranged from 23.04 to 32.58 nm and from 37.99 to 79.59 nm via AV and hibiscus sabdariffa flowers, respectively. Finally, the particle size of the Ag/ZnO nanocomposite ranged from 22.39–40.05 nm and from 59.73–87.05 nm via the AV and hibiscus sabdariffa flowers, respectively.

In parallel with the shell model using the harmonic oscillator's single-particle wave functions, the Hartree-Fock approximation was also used to calculate the neutron skin thickness, the mirror charge radii, and the differences in proton radii for 13O-13B and 13N-13C mirror nuclei. The calculations were done for both mirror nuclei in the psdpn model space. Depending on the type of potential used, the calculated values of skin thickness are affected. The symmetry energy and the symmetry energy's slope at nuclear saturation density were also determined, and the ratio of the density to the saturation density of nuclear matter and the symmetry energy has a nearly linear correlation. The mirror energy displacement was calculated, and the findings corresponded well with the available experimental data for the binding energies of the studied mirror nuclei. The measured values of the symmetry energy coefficient for the pair of mirror nuclei agreed with the computed ones, and this coefficient's value rises exponentially as the difference in charge radius increases.

In this research, the use of natural materials like wool and cannabis as intermediate reinforcement for prosthetic limbs due to their comfort, affordability, and local availability was discussed. As part of this study on below-the-knee (BK) prosthetic sockets, two sets of samples were made using a vacuum method. These sets were made of natural fiber-reinforced polymer composites with lamination 80:20: group (Y) had 4 perlon, 1 wool 4 perlon, and group (G) had 4 perlon, 1 cannabis 4 perlon. The two groups were compared with a socket made of polypropylene. Tensile testing was used to determine the mechanical characteristics of the socket materials. The Y group has a yield stress of 17 MPs, an ultimate strength of 18.75 MPa, and an elastic modulus of 4.021 GPa, while for the G group, these values are 12.75 MPa, 18.84 MPa, and 4.076 GPa, respectively. The fatigue test was used to evaluate the failure characteristics of the socket. An F-socket was utilized to test the interface compression between both the limb and the socket. For the Tekscan sensor, the calculated pressure in the medial region is 350 K Pa, while it is 330 KPa in the posterior region. Solid Works software was used to draw a prosthetic socket for the numerical study. The failure safety agent for the composite material for group Y was 1.26. The finite element method (ANSYS Workbench 14.5) was used to look at the fatigue characteristics to detect the maximum stress, safety factor, and total deformation.

This study investigated the effect of applying an external magnetic field on the characteristics of laser-induced plasma, such as its parameters plasma, magnetization properties, emission line intensities, and plasma coefficients, for plasma induced from zinc oxide: aluminum composite (AZO) at an atomic ratio of 0.3 wt%. Plasma properties include magnetization and emission line intensities. The excitation was done by a pulsed laser of Nd:YAG with 400 mJ energy at atmospheric pressure. Both the electron temperature and number density were determined with the help of the Stark effect principle and the Boltzmann-Plot method. There was a rise in the amount of (ne) and (Te) that was produced by applying a magnetic field and, on the other hand, using the 532 nm wavelength rather than the fundamental wavelength of a laser. The emission lines in the atmosphere's plasma have an appearance of Lorentzian shape. The 532 nm laser exhibited a decrease in both the Larmor radius and the confinement factor compared with the 1064 nm laser. By applying the magnetic field, the Laser Induced Breakdown Spectroscopy (LIBS) intensities increased by 1.44 times when compared to the emissions before applying the field. In addition, the spectral line intensities improved with the fundamental wavelength compared to the second harmonic frequency as a result of the increase in the extracted materials. This is due to the increase in the absorbance of the laser by the target, as some of these materials are excited, so they act as emission sources, which makes them more detectable.

Manganese-zinc ferrite MnxZn1-xFe2O4 (MnZnF) powder was prepared using the sol-gel method. The morphological, structural, and magnetic properties of MnZnF powder were studied using X-ray diffraction (XRD), atomic force microscopy (AFM), energy dispersive X-ray (EDX), field emission-scanning electron microscopes (FE-SEM), and vibrating sample magnetometers (VSM). The XRD results showed that the MnxZn1-xFe2O4 that was formed had a trigonal crystalline structure. AFM results showed that the average diameter of Manganese-Zinc Ferrite is 55.35 nm, indicating that the sample has a nanostructure dimension. The EDX spectrum revealed the presence of transition metals (Mn, Fe, Zn, and O) in Manganese-Zinc Ferrite. The FE-SEM results of MnZnF showed uniform spherical structures. VSM was used to study the change in magnetization, the saturation magnetization, (Ms) value of the samples. The measurement of VSM indicated that the MnZnF exhibits ferromagnetic behavior with coercivity Hc (0.0014 Gauss), remanent magnetization (Mr) (0.202 emu/gr), and saturation magnetization Ms (2.69 emu/g)

The current study used satellite data and a geographic information system (GIS) to detect changes in land use and land cover (LULC) in Al-Hillah city, central Iraq from 1990 to 2022. The study aimed to calculate the NDVI, NDWI and LULC of Al-Hillah using Landsat 5 TM and Landsat 8 OLI images. The results showed that there was an apparent expansion in the urban area from 20.5 km2 in 1990 to about 57 km2 in 2022. On the other hand, there is a slight increase in agricultural areas and water, while the barren area decreased from 168.7 km2 to 122 km2 in 2022. Long-term urban planning, which is based on LULC analysis, is an effective tool for decision-makers to study future patterns in urban expansion in parallel with the expected rise of the population in Iraq in the coming years. While there was a slight increase in water and agricultural areas. The continuous urban expansion led to a reduction in barren areas in favor of urban areas. Urban planning for a long period, which is based on LULC analysis, where demographic changes greatly affected land use in the city of Al-Hillah, and the increase appears significantly in the urban and residential areas.

This research aims to study the optical characteristics of semiconductor quantum dots (QDs) composed of CdTe and CdTe/CdSe core-shell structures. It utilizes the refluxed method to synthesize these nanoscale particles and aims to comprehend the growth process by monitoring their optical properties over varied periods of time and pH 12. Specifically, the optical evolution of these QDs is evaluated using photoluminescence (PL) and ultraviolet (UV) spectroscopy. For CdTe QDs, a consistent absorbance and peak intensity increase were observed across the spectrum over time. Conversely, CdTe/CdSe QDs displayed distinctive absorbance and peak intensity variations. These disparities might stem from irregularities in forming selenium (Se) layers around CdTe QDs during growth stages, which could potentially induce quenching in the emission spectrum. The optical examinations unveiled a discernible redshift towards higher wavelength values as the reaction progressed. This spectral shift was coupled with an enlargement in QDs size and a decrease in the energy gap. Using PL and UV analysis techniques enabled a comprehensive study of the optical attributes of the CdTe and CdTe/CdSe QD systems. Our findings underscored the influence of growth conditions and shell materials on the optical properties of QDs. The observed changes in absorbance, peak intensity, wavelength values, QDs size, and energy gap with increasing reaction time provided valuable insights into the growth dynamics of these QD structures.

In this study, optical fibers were designed and implemented as a chemical sensor based on surface plasmon resonance (SPR) to estimate the age of the oil used in electrical transformers. The study depends on the refractive indices of the oil. The sensor was created by embedding the center portion of the optical fiber in a resin block, followed by polishing, and tapering to create the optical fiber sensor. The tapering time was 50 min. The multi-mode optical fiber was coated with 60 nm thickness gold metal. The deposition length was 4 cm. The sensor's resonance wavelength was 415 nm. The primary sensor parameters were calculated, including sensitivity (6.25), signal-to-noise ratio (2.38), figure of merit (4.88), and accuracy (3.2). In the current study, the refractive index values of sucrose and water solutions at different concentrations, which were used as a calibration method, were calculated to be (1.346, 1.359, 1.382, and 1.39). It was found that when the refractive index of the sensitive medium increases, the length of the resonant wavelength increases due to the decrease in energy.

This work concerns the synthesis of two types of composites based on antimony oxide named (Sb2O3):(WO3, In2O3). Thin films were fabricated using pulsed laser deposition. The compositional analysis was explored using Fourier transform infrared spectrum (FTIR), which confirms the existence of antimony, tungsten, and indium oxides in the prepared samples. The hall effect measurement showed that antimony oxide nanostructure thin films are p-type and gradually converted to n-type by the addition of tungsten oxide, while they are converted almost instantly to n-type by the addition of indium oxide. Different heterojunction solar cells were prepared from (Sb2O3:WO3, In2O3/Sb2Se3/c-pSi) contained forms from two layers the first was Sb2Se3 and the second was (Sb2O3):(WO3, In2O3) nanostructured thin films. The heterojunction (Sb2O3:15%WO3 Sb2Se3/c-pSi showed a maximum conversion efficiency of 9% and exhibits an open circuit voltage (Voc) of 300 mV, short circuit current (Isc) of 35 mA, and a fill factor of 0.429 at an intensity of illumination of 100 mW/cm2.

Water quality sensors have recently received a lot of attention due to their impact on human health including environmental sensors especially that based on carbon quantum dots (CQDs). In this study, CQDs were prepared using the electro-chemical method, where the structural and optical properties were studied. These quantum dots were used in the environmental sensor application after mixing them with three different materials: CQDs, Alq3 polymer and CQDs and Alq3 solutions using two different methods: drop casting and spin coating, and depositing them on silicon. The sensitivity of the water pollutants was studied for each case of the prepared samples after measuring the change in resistance of the samples at a temperature of 30 oC. Through the results, it was found that the highest sensitivity of sample 3 (CQDs solution) to the carbon continuous dot was in the case of the contaminant fructose and was 99.55%, while the highest sensitivity of sample 4 (Alq3 solution) was for the one sensitive to the contaminant (mercury chloride) and was 81. As for sample 1 (CQDs/Alq3 composite films by drop casting), the highest sensitivity was in the case of detecting the contaminant lead chloride and was 80. The results showed that the best sensor was obtained using a spin-coating technique when the solution sample of CQDs+Alq3 was placed on a silicon slide in fructose and the sensitivity was 200%. This demonstrates the importance of quantum dots in measuring the sensitivity of water pollutants. The thin film thickness was measured to be 500 nm.