Kuwait Journal of Science

Cross sections data adjustment for KRITZ-2:13

2021-10-10T01:20:55+03:00

Over the past years, the cross-sections reaction data has been re-evaluated several times, in order to approximate the nuclear model measurements with the predictions with great reliability. In our work, uncertainty analysis caused by the data on the neutron factor (K_eff) and the reactivity temperature coefficient (RTC), in addition to nuclear data adjustment have been done for KRITZ-2:13 reactor, with ENDF/B - VII.1, ENDF/B - VIII.0 and JENDL - 4.0 evaluations by the nuclear code MCNP6.1. Our analysis detects that the greatest uncertainty on K_eff and RTC in the studied libraries comes from the capture and fission reaction contributions respectively, for U-238 and U-235. The previous reactions and their covariances were adjusted using the generalized least squares method (GLLSM), in order to contribute to improve the data needed for neutron simulation of experiments and to ensure the installations safety, where K_eff and RTC represent neutron parameters reflecting the modification effects in the data.

Enhancement of optical chaos generator using double delayed feedback

2022-02-12T03:19:02+03:00

Chaotic lasers are widely used in secure communication, optical detection and other applications due to their noise-like randomness, excellent anti-jamming and other advantages. This research looks into the chaotic laser's performance at a low cost. The performance related to a semiconductor laser with double delayed feedback is observed and its characteristics are determined in experimental research utilizing OptiSystem simulator. The chaotic laser output is fed back to the Mach-Zehnder modulator (MZM) to make the original system. The gain coefficient changes dynamically, and a second time delay is introduced into the system. The feedback time and feedback strength of the improved chaotic system are studied under varying input bias current, frequency and modulation beak current. Bifurcation diagram results show that the chaotic laser output by the optoelectronic oscillator (OEO) is more complex and has lower delay characteristics. This method does not increase too much Under the premise of system cost, more complex chaotic signals can be generated, and the signal delay characteristics can be reduced, which is conducive to improving the security of the communication system.

Modeling of field emission from laser etched porous silicon

2022-02-15T21:13:05+03:00

In many modern sciences, electron transfer is required, such as electron microscopes, microwaves, and screens. There have been numerous reports of the formation of microstructures on silicon surfaces using lasers in halogen-containing media and their optical, electrical and other physical properties. A silicon microstructured field emitter is modeled with Fowler-Nortium field diffusion theory, and the breakdown currents are consistent. Breakdown voltage, field gain coefficient, current and current density, and emitter region (in case of breakdown) are considered in the simulation. Comparison between simulation and experimental results shows that the microstructure has field emitter properties and can be used as a new field emitter.

Diffusion coefficient calculation of iron in liquid lead using molecular dynamics method with new mixing rule for Lennard-Jones potential parameters

2022-01-04T08:51:43+03:00

The diffusion coefficient data of materials are crucial for several applications, and can be calculated theoretically up to considerable accuracies. Using molecular dynamics simulation it is possible to compute this property for several conditions as temperature and pressure. The corrosion phenomena of steel types in the fast nuclear reactor can be correlated and studied based on the the diffusion process of iron atoms that dissolve into a liquid lead coolant via molecular dynamics methods using certain potential energy. A widely type of the interatomic interaction potential of
materials is the Lennard-Jones potential. Regarding this potential, for a pair of different elements A and B, we can determine the potential parameter (

Scattering of gamma radiation by air in the ambient environment using gamma ray spectrometry

2022-02-14T08:41:08+03:00

The intensity of gamma radiation reduces as it traverses through matter. The gamma radiation from earth’s surface is attenuated by non-radioactive burden between the ground and the detector. The relative intensity of unscattered to scattered gamma radiation by air in ambient atmosphere is measured using in-situ gamma spectrometric method. The air thickness up to 300 cm is used for studying attenuation of terrestrial gamma radiation. No significant attenuation is measured up to 100 cm thickness of air between the detector and the ground. The attenuation by air is found decreasing with increasing thickness of air. Also, the attenuation of terrestrial gamma radionuclides (⁴⁰K) is found higher than ²³⁸U and ²³²Th as ⁴⁰K has lower energy compared to them.

Investigation of V2O5-ZnAl2O4 composite nanoparticles for C-band microstrip patch antenna applications

2022-02-08T07:17:18+03:00

This paper reports the prototype fabrication and characterization of microstrip patch antenna using the sol-gel derived composite nanoparticles of vanadium pentoxide oxide (V₂O₅) and zinc aluminate (ZnAl₂O₄). The prepared composite nanoparticles were characterized using X-ray diffraction (XRD), which exhibited the dominant peaks of ZnAl₂O₄ and V₂O₅. The crystallite size of the nanoparticles was estimated to be 16 nm. The sample was also studied using the Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), and energy dispersive spectroscopy (EDS) to examine the functional groups morphology and elemental composition present in the composite nanoparticles. Further, these nanoparticles were employed in fabricating the prototype microstrip patch antenna to evaluate its characteristics. The fabricated antenna showed its return loss of -17.13 dB at a resonant frequency of 4.64 GHz.

Transparent dielectric TiO2/SiO2 coatings for thermal shielding and self-cleaning applications

2022-02-09T10:18:49+03:00

Economical fabrication of one-dimensional dielectric reflectors using the hybrid sol-gel spin coating process is significant compared to sophisticated chemical and physical vapor deposition techniques. In this work, we preferred the TiO₂ and SiO₂materials to fabricate dielectric reflectors due to their high refractive index contrast and easy tailor-ability of the reflectance window in the spectral region of interest. Here, we fabricated the near-infrared reflectors composed of TiO₂/SiO₂ films with a minimum number of stacks to attain the constructive interference of incident light so that maximum reflectance can be assured in the specific spectral region. X-ray diffraction (XRD) studies of the monolayer TiO₂ and SiO₂ confirmed the existence of anatase-TiO₂ and amorphous-SiO₂ phases, respectively. The TiO₂ and SiO₂ films were found to have refractive indices of 2.6 and 1.5, respectively, as measured by spectroscopic ellipsometry.The field-emission scanning electron microscopy (FESEM) analysis evidenced the fabrication of 2.5 stacks of TiO₂/SiO₂films (TiO₂/SiO₂)_2.5. The reflectance measurement revealed 100 percent reflection in the near-infrared region having its center wavelength of 833 nm. In addition, we have examined the water contact angle of the reflector ( 2.5 stacks) using the sessile drop technique and found its contact angle of 29.3^O_,which suggests its anti-fogging and self-cleaning applications.

Sol-gel synthesis of CaZnAl2O4 ceramic nanoparticles and investigation of their properties

2022-03-15T22:41:32+03:00

Dielectric ceramic materials are well-recognized in the semiconductor industry because of their unique properties such as thermal stability, chemical resistance, and crystallinity. Despite their potential applications, these are also demanded in wireless communication. This paper reports the structural, morphological, and dielectric properties of sol-gel derived CaZnAl₂O₄ceramic nanoparticles. X-ray diffraction (XRD) analysis exhibited the polycrystalline characteristic of the CaZnAl₂O₄ nanoparticles with their crystallite size of 13 nm. We have investigated the functional groups present in the ceramic nanoparticles, which confirmed the relevant vibration peaks of various functional groups. Surface morphology study demonstrated the preparation of spherical grains with their mean diameter of 16nm. The concentric rings also confirm the crystallinity of the nanoparticles that appeared in the selected area diffraction pattern. Furthermore, we analyzed the nanoparticles' dielectric properties, which showed the variation of dielectric permittivity from 23.76 to 21.67 as a function of increased frequency. Similarly, the dielectric loss is found to decrease from 0.047 to 0.039. As a result, the conductivity increased from 1.324 μS/m to 3.639 μS/m as a function of applied frequency.

Newtonian hydro-thermal fluid flow phenomena through a sudden expansion channel with or without baffles

2022-04-06T07:16:49+03:00

This work aims to study the different characteristics of Newtonian fluid flow and heat transfer through a 1:3 sudden expansion channel with or without plane baffles using the finite volume method. The flow is assumed viscous, incompressible, unsteady, and laminar. The effect of Reynolds number on recirculation characteristics and velocity profiles have been studied for a wide range of Reynold number (0.1 – 200). The velocity and pressure profiles, skin friction coefficient, friction factor, average Nusselt number, and pumping power have been examined for both the cases. It is observed that in the presence of baffles, the flow dynamics and heat transfer characteristics are more influenced than the case of smooth channel. Furthermore, the enhancement of heat transfer rate is affected more when the height of the baffle is increased and the same is decreased when the thickness of the baffle is increased.

Investigation of biomimetic hydroxyapatite formation on titania nanoparticles and lobed nanotubes

2022-03-18T08:21:32+03:00

Anodizing method was used to produce TiO₂ nanotubes (TNTs) on Ti metal bases. These tubes were transformed to lobed nanotubes (LNTs) by heating at 600⁰C as scanning electron microscopy (SEM) images showed. Rapid break down anodizing (RBA) technique was utilized to produce TiO₂nano particles (TNPs). These particles were deposited on LNTs by electrophoretic deposition (EPD) method. X-ray diffraction (XRD) test showed the polycrystalline composition of the formed LNTs and amorphous structure of TNPs. The bioactivity of LNTs and the deposited TNPs on the LNTs were tested by immersing them in simulated body fluid (SBF) for one month. For the two samples XRD patterns showed the appearance of small peaks of hydroxyapatite (HAp), which indicates the bioactivity of these samples. SEM images show that the HAp layer on LNTs was in the form of protrusions, while on TNPs it was in the form of crossed filaments.

Radar cross section (RCS) of perfect electromagnetic conductor (PEMC) cylinder by a Laguerre–Gaussian beam

2022-04-11T02:55:49+03:00

The Radar Cross Section (RCS) of perfect electromagnetic conductor (PEMC) cylinder using an incident LG beam have been investigated. Laguerre–Gaussian (LG) beam potential function is used to expand the incident and scattered electromagnetic (EM) field components. The co- and cross-polarized scattered field coefficients are determined by applying the PEMC boundary conditions at the interface i.e., . The obtained values for co- and cross-polarized scattered field components would helpful to find out the scattered field distribution. The comparison of our results for (PEMC) and (PMC) for fundamental LG beam with beam mode , , i.e., matches with the gaussian beam scattering as witnessed by published work. The effects of OAM mode index , beam waist radius , admittance parameter ( ), and PEMC cylinder radius on (RCS) have been analyzed.

Assessment of health risk due to Pb, Cd, and Cr concentrations in imported cheese samples in Iraq markets

2022-04-03T07:28:06+03:00

The aim of this study is to determine three heavy metals (Pb, Cd, and Cr) concentrations in cheese samples in Iraq markets that are produced in Iran and Turkey. The concentrations of Pb, Cd, and Cr were measured using atomic absorption spectroscopy. Human health risk parameters, such as Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), and Carcinogenic risk (CR) due to heavy metals were calculated in all cheese samples of the present study. The average value concentrations of Pb, Cd, and Cr in cheese samples made manufactured in Iran were 4.33±0.57 mg/kg, 0.135±0.03, mg/kg, and 0.183±0.12 mg/kg, respectively. While those which were made in Turkey, the values were found to be 3.89±0.63 mg/kg, 0.167±0.032 mg/kg, and 0.105±0.07 mg/kg, respectively. The average values of HI in Iranian and Turkish cheese samples were 0.526±0.07 and 0.483±0.26, respectively. While the average values of CR×10^-6 for Pb, Cd, and Cr in Iranian cheese samples were 0.006±0.0007, 1.13±0.0007, and 0.0056±0.7, respectively. But in Turkish cheese samples were 0.005±0.0008, 0.37±0.07, and 0.65±0.4, respectively. The heavy metal concentrations in the present study were found to be of no statistical significance, compared to the Iranian and Turkish cheese samples, where P-value was (P > 0.05). Most values for Pb, Cd and Cr concentrations were found to be higher than the allowed limits according to EU Regulations, while the health risk parameters were within the accepted worldwide average limits. Therefore, it can be concluded that most cheese samples have no health risks by consuming this cheese by consumers in Iraq.

Thermo-mechanical fe-demo based calculations of high entropy alloys (HEAs) (Fe-Ni-Cx (x=0.3-0.5) ternary alloy system using calphad method

2022-04-28T06:20:13+03:00

The given research shows the thermodynamic analysis and calculation of the basic thermal properties of the high entropy alloy Fe-Ni-Cx (x=0.3-0.5) of concentration. The system is investigated through Thermo-calc package with FEDAT databases and Calphad method. The evaluation of interactions is found maximum at 0.04070 J/m2 of interfacial energy in the Fe-Ni-C
ternary alloy system. The FCC_A1 phase is found the phase associated with highest molar volume in the Fe-Ni-Cx (x=0.3-0.5) ternary alloy system. The phase FCC_A1 is having austenite coordination with increasing density and apparent heat capacity. The temperature variation results the composite phases to be disappears with required level. The system is found highest apparent heat capacity 0.39269 J/mol. The density of phases becomes constant and it indicates
the rare temperature withstanding phases. The fluctuations in the density of phases are changing with temperature as a result of phase’s nature and stability. The better magnetic properties are found for Basic centered cubic structure with highest interfacial energy. The alloy shows better magnetic coordination and thermodynamic properties enhancement for further analysis.

Production of titanium oxide nano wires with bundle structure using single anodic process

2022-04-11T13:00:44+03:00

In a single process, the surface of Ti was transformed into titanium oxide nanowires (TNWs) at room temperature. The rapid breakdown anodizing method (RBA) of producing deposited spherical nanoparticles was modified. Instead, TNWs attached to the Ti metal base were formed. To slow down the reactions of these processes, 25,50, and 75wt % glycerol were added separately to the anodizing solution of RBA. The results of the X-ray diffraction (XRD) tests revealed the amorphous structure of the formed TNWs for all samples. The produced TNWs had the shape of micro bundles with nanowires. Their diameters were less than 50 nm, as shown by scanning electron microscope (SEM) images. The prevalence of titania bundles was more intense when a lower amount of glycerol was used. The tallest length of the nanowires decreased from 32μm to 8μm with the increase of glycerol; so by using a suitable electrolyte solution, the
anodizing process can be effective for controlling the size of TNWs. The decrease in atomic percent oxygen with increasing glycerol was confirmed by energy dispersion X-ray (EDX) spectra.

Investigating the effects of the different rhodamine 6G laser dye volume ratios on the optical properties of PMMA/PC films

2022-05-25T03:12:53+03:00

Rhodamine 6G – polymethylmethacrylate/polycarbonate (Rh6G–PMMA/PC) were prepared by a casting method at room temperature with diverse volume ratios of Rh6G dye solution (5, 10, 15, 20 and 25) ml. The as-prepared films were categorised via UV–Vis spectrophotometer, and the optical properties were investigated in the wavelength range of (200-800) nm. The absorption peaks for pure PMMA/PC film were affected by inserting Rh6G dye solution, the wavelength of absorption peak of pure PMMA/PC film is at 300 nm and 340 nm while there are different behaviour at different concentration of RG6 after mixing with PMMA/PC films; there are red shift for concentrations (10 and 25 ml) of RG6 after mixing with PMMA/PC films by appear another peaks at 530 nm and 535 nm respectively.

In addition, there is a blue shift for concentrations (15 and 20 ml) of RG6 after mixing with PMMA/PC films, as evidenced by the appearance of new peaks at wavelength 265 nm. Furthermore, new peaks appeared and were absorbed while the energy band gap was influenced, with values ranging from 4.3 eV for pure PMMA/PC film to 4.18 eV for mixtures 10 & 25 ml concentration of Rh6G/ PMMA/PC belonging to the red shift to 4.9 eV and 4.85 eV for mixtures 15 and 20 ml concentration of Rh6G/ PMMA/PC belonging to the blue shift.

Impedance analysis of single walled carbon nanotube/vinylester polymer composites

2022-05-21T23:01:01+03:00

This study presents impedance characteristics of single walled carbon nanotube/vinylester (SWCNT/VE) glass fiber reinforced polymer (GFRP) composites. The impedance measurements were carried out as a function of the frequency over range of 10^-2 and 10⁷ Hz at various temperatures between 300 K and 420 K. Bode and Nyquist plots of real and imaginary parts of complex impedance (Z*) were obtained and Cole–Cole approach was used to interpret the impedance characteristics. The results indicated that the bulk resistance of the material decreases significantly as the temperature increases. The frequency-dependent AC conductivities were calculated using the complex impedance data and dimensions of specimen. It has been observed that the alternating current values are compatible with the Jonscher’s power law. The behavior of dielectric constant and loss factor at the various temperatures were analyzed as a function of applied frequency. While the sample exhibited high dielectric permittivity in the low frequency region with the Maxwell-Wagner-Sillars (MWS) effect, it was observed that the permittivity decreased as a result of the dipoles' inability to rotate themselves in the field direction at high frequencies. No dielectric relaxation peak was observed in the loss spectra in our limits. From the results, it can be said that the contribution to the dielectric relaxation is due to the interface polarization and DC conductivity. Electric modulus formalism was also used to describe the conductivity and dielectric relaxation processes of SWCNT/VE binary composite. It was found that the obtained peak maximums shifted to higher frequencies as the temperature increased. It is concluded that the frequency regime below the peak maximum defines the range of mobile charge carriers, and in the regime above the maximum, the charge carriers are limited to short distance potential wells.

Mathematical modelling and analysis of temperature effects in MEMS based bi-metallic cantilever for molecular biosensing applications

2022-06-21T23:11:44+03:00

As Lab-on-Chip platforms with micro-and nano-dimensions evolve biosensors using miniaturized and high-sensitivity cantilevers are becoming more attractive. Although these sensors function in non-isothermal situations, computational mathematics generally ignores the temperature. Conversely, biosensors can’t be designed with a single-layered cantilever. Yet, in Nano-Electro-Mechanical-Systems, the influence of temperature is more likely to be dominant since the surface-to-volume ratio is higher. In the context of this conclusion, the mathematical modelling comprises temperature and the associated material attributes. This work presents a simple and direct analytical technique for analysing the control of bimetallic cantilevers with NEMS-based sensing and actuation mechanisms. Methodological techniques were used to develop and solve some well-known models of mathematical equations. Parametric analysis data is a major factor in the functioning of all of the other works studied. The findings of FEA comparisons and experiments reveal that the mathematical model's predictions are more than 20% correct.

Study physical characteristics of Polyvinyl Alcohol/Carboxymethyl cellulose blend films

2022-07-23T05:55:46+03:00

The pure polyvinyl alcohol (PVA), pure CarboxyMethyl Cellulose (CMC), and CMC/PVA blend films with different amounts (0.1, 0.2, 0.25, 0.3 and 0.4 g) of both polymers were prepared by simple solution casting method in this study. FTIR and UV-Vis spectroscopies were used to characterize the physical properties of as-prepared samples. FTIR spectroscopy
revealed that the original bonds for both PVA and CMC polymers were appearing in blend polymer, but some bonds referring to CMC polymer seemed in high amounts of this polymer. Optical characteristics showed that the absorbance and absorption coefficient of PVA polymer is improved with increased amounts of CMC polymer. The direct relationship between absorbance and absorption coefficient with amounts of CMC polymer will be established. Furthermore, the energy gap of pure CMC (5.24 eV) and pure PVA (4.74 eV) polymers films were estimated. Tuning Eg toward lower value due to change CMC polymer concentration of blend polymer (PVA/CMC) film was achieved. From the findings of optical properties, it concludes that the blend film has the highest absorbance and absorption coefficient and lowest
transmittance in the UV region compared to pure PVA and CMC polymers.

Wormhole solutions and energy conditions in f(R; T ) gravity with exponential models

2022-06-01T13:14:05+03:00

In the present article, we examine the solutions of the wormhole by using inhomogeneous spacetime in modified $f(R,T)$ theory of gravity. We take two dissimilar models of $f_{1}(R)$ that are $f_{1}(R)=R-\alpha\gamma(1-e^{-\frac{R}{\gamma}})$ known as exponential gravity model and $f_{1}(R)=R-\alpha\gamma tanh(\frac{R}{\gamma})$ known as Tsujikawa model, where $\alpha,~\gamma$ are model parameters. We explore the feasible solutions for these models. Moreover, we discuss analytically as well as graphically, different properties of these model of wormholes by giving suitable values to the model parameters. We then consider two specific shape functions i.e. $F_s(r)=r_0\frac{Log(r+1)}{Log(r_0+1)}$ and $F_s(r)=\frac{r}{e^{r-r_0}}$ and energy conditions have been explored using the above mentioned two models. Conclusively, we find that obtained wormhole solutions are physically acceptable with the considered exponential and Tsujikawa gravity models with or without the presence of exotic matter.

The effect of mixing nanoparticles on the suspension physical stability

2022-06-02T07:29:49+03:00

Energy transfer in a hybrid mixture of Rhodamine 6G (Rh6G) dye laser as a donor and nanoparticles (NPs) as an acceptor were studied. The absorption spectra of 1×10-5 M of Rh6G in distilled water showed an increase in peak intensity upon addition of NPs. Notably, the spectra were improved upon addition of Aluminum Oxide (Al2O3) NPs. The addition of NPs quenches the fluorescence spectra of Rh6G due to Förster resonance energy transfer (FRET). The efficiency of this energy transfer increases with an increasing concentration of NPs, and a best value of efficiency of energy transfer was found for the Rh6G/Magnesium Oxide (MgO) NP system. A similarly strong relationship was also found for for the Rh6G/Al2O3 NP system.

Controlling the nanoparticle size of silica in an acidic environment by using a strong magnetic field and a modified sol-gel techniques

2022-09-07T03:53:32+03:00

In this study, we were able to create highly dispersed silica nanoparticles with diameters of less than one nm by changing the sol-gel technique. During the poly-condensation process, a strong magnetic field was applied to the silica sol to control particle size. The size of silica nanoparticles has a substantial impact on preparation elements such pH, magnetic field intensity, and exposure time. These parameters can be changed in a systematic manner to reduce or increase particle size. A dynamic light scattering test was also used to investigate the effect of a magnetic field on the particle size and dispersion of silica dust. Despite the fact that silica is naturally diamagnetic, the magnetic field has a considerable impact on their size growth. Magnetic fields altered the typical influence on silicon structure, resulting in crystal formation in the silicon sample under consideration. Many applications require small particle sizes and/or a narrow particle size dispersion. The building blocks of nanotechnology are usually made of low-dimension particles. The experts concluded that additional research into such strange phenomena will be required in the future.