Kuwait Journal of Science最新文献

The current study aims to evaluate the effectiveness of undoped (CoFe₂O₄) and aluminium-doped cobalt spinel ferrite (CoFe_1.1Al_0.9O₄) nanoparticles as photocatalysts in the process of photocatalytic degradation of organic naphthol blue black (NBB) dye. In the sol-gel auto combustion method, a combination of metal nitrates, citric acid, sodium hydroxide, and liquid ammonia was utilized as the raw chemical ingredients for synthesizing nanoparticles of CoFe_2-xAl_xO₄ (x = 0.0, 0.3, 0.6, 0.9, 1.2, 1.5) spinel ferrites. The nanoparticles were subjected to various characterization techniques including thermal analysis (TGA/DTA), X-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), and UV–visible spectroscopy for comprehensive analysis. The XRD analysis confirmed the presence of a spinel cubic structure in the synthesized spinel ferrite nanoparticles. The interplanar distance (d) and crystalline size (D) were determined using Bragg's equation and Scherrer's relationship, respectively. The morphological characteristics and elemental composition of the spinel ferrites were confirmed through FE-SEM and EDS. Furthermore, the UV spectrum of the synthesized photocatalyst was investigated to compare the energy band gap between undoped and Al-doped cobalt spinel ferrites. The analysis of photoluminescence (PL) spectra was conducted to investigate the dynamics of charge carriers, focusing on their transfer, relocation, and recombination processes. The surface area of the synthesized photocatalyst ranged from 3.525 to 16.113 m²/g. Photocatalytic degradation of naphthol blue black (NBB) dye was carried out under visible light exposure utilizing both cobalt spinel ferrite nanoparticles without doping and those doped with aluminium. Several factors, including pH level, H₂O₂ concentration, amount of photocatalyst (spinel ferrite) and initial dye concentration, were considered through the photocatalytic degradation of NBB dye. The highest percentage degradation (%) of NBB dye was determined at pH 11. For NBB dye with an initial concentration of 20 ppm, the maximum degradation was achieved using 200 mg of spinel ferrite nanoparticles per 100 mL dye solution under visible light irradiation for 40 min.

This article presents a theoretical investigation of the problem of free fall of a spherical particle in a viscous fluid. The classic Boussinesq-Basset-Oseen (BBO) model for particle motion in laminar flow was modified for generalized flow by using a drag law that is applicable for $0<Re\le 2.0\times {10}^5$. By assuming that the acceleration in the Basset force integral is constant, the Basset force effect was approximated to form an integrated added mass coefficient. Consequently, the integro-differential equation of the BBO model was transformed to a first-order nonlinear ordinary differential equation that accounts for the Basset force effect and was solved using the continuous piecewise linearization method (CPLM). The CPLM algorithm was developed based on the jerk-velocity relationship and is applicable to zero and non-zero initial conditions, steady motion, increasing or decreasing velocities and the corresponding acceleration and jerk responses. The CPLM algorithm was shown to predict published experimental results accurately and compared very well with numerical solutions and existing analytical solutions. Examination of the fall response under varying parameters showed that the fall distance, fall time and terminal velocity depend strongly on the sphere diameter, sphere density, and the density and viscosity of the fluid medium. Also, an analytical solution for the power dissipated in the fluid medium as the sphere falls to reach its terminal velocity was derived. The power dissipated was found to increase exponentially as the initial velocity deviates positively from the terminal velocity.

Photovoltaic systems convert solar irradiance into electricity. Due to some factors, the amount of solar irradiance arriving at the solar photovoltaic collector at a specific location varies. The goal of this study was to develop a mathematical model for predicting the performance of a photovoltaic system, which depends on the amount of solar irradiance. A novel model for solar irradiance in the form of a delay differential equation is introduced by including the factor of delayed solar irradiance, hour angle and the sun's motion. The simulation study is carried out for the three scenarios of weather conditions: a clear day, a slightly cloudy day, and a heavily overcast day. The numerical solution is obtained by adopting the 4^th-order Runge Kutta method coupled with a parameter fitting technique, the Nelder Mead algorithm, which is implemented by using MATLAB software. The data from a solar plant in Pahang, Malaysia, was used for model validation and it is found that the prediction profile for solar irradiance aligns well with the intermediate and decay phases, but deviates slightly during the growth phase. The output current and power for the solar photovoltaic panel were treated as time-dependent functions. As the solar irradiance increases, the output current and power of the solar panel will increase. The result showed that the maximum output current and output power of STP250S-20/Wd crystalline solar module decreased by 42% and 76%, respectively, during slightly cloudy and heavily overcast conditions when compared to clear days. In other words, the performance of a photovoltaic module is better on clear days compared to cloudy days and heavily overcast. These findings highlight the relationship between delayed solar irradiance and the performance of the solar photovoltaic system.

The lack of standardized protocols for mead production leads to a degree of unpredictability in the final alcoholic product due to a limited understanding of precursor components' interactions in raw materials. Therefore, this study endeavors to simplify mead production by conforming to Brazilian legislative guidelines through an accessible wort standardization process. To mitigate variability in final products, including grape wine standards, it is necessary to investigate more dependable and accessible analytical methods for small producers. To study this standardization, a 120-day fermentation was carried out with monthly sampling, where sugars were evaluated: glucose, fructose, sucrose, and ethanol, using inexpensive methods. The results showed that most of the alcoholic fermentation takes place in the first 30 days, stabilizing afterwards. It was also clear that glucose has the best correlation with the generation of ethanol above 0.98 and is the most accessible method because, in addition to being found in any pharmacy, it is accurate, cheap, and fast. It has also been shown that there is a higher conversion with a lower concentration of honey in the wort, which is interesting in terms of cost-benefit.

The present study provides an environmentally benevolent synthesis of titanium dioxide nanoparticles (TiO2 NPs). Morphological characteristics of the fabricated nanoparticles were assessed by using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-Spectroscopy. The XRD pattern of the synthesized nanoparticles showed that the nanoparticles had a tetragonal crystalline structure with a particle size of 20–40 nm. The photocatalytic efficacy of the developed nanomaterials was investigated in relation to indigo carmine, bromothymol blue, and rhodamine b dye. The presence of a photocatalyst leads to an improved performance, causing a decline in dye concentration with increasing irradiation time. The highest dye degradation of about 95 % was observed against indigo carmine dye. The green synthesized TiO₂ NPs exhibited a significant zone of inhibition (23 mm) in antibacterial activity against Bacillus at the concentration of 70 mg/mL. The developed nanoparticles demonstrate 81.29 % DPPH radical scavenging activity at the concentration of 60 μg/mL.

Impregnation of MgO nanocatalysts on montmorillonite-K10 (MTe) and kinetics studies on transesterification reactions for biodiesel production using Cerbera odollam oil have been conducted. The impregnation process of nanocatalyst into MTe was carried out by mixing the MgO nanocatalyst with MTe dispersed in an ethanol solution. The MgO-MTe product was characterized using X-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM). Transesterification reaction process of Cerbera odollam oil using MgO-MTe catalyst carried out in batch modified-microwave reactor with various oil/methanol ratios, reaction temperatures, reaction time, and the percentage weight of catalyst. Furthermore, the reaction kinetics analysis is done using the pseudo-first-order reaction. The quality of biodiesel was determined using the American society for testing and materials (ASTM) method for biodiesel test. The results show that with the increasing percentage weight of catalysts, product increases with optimum conditions obtained on the weight of catalysts 7% (w/w). Meanwhile, the ratio of oil-to-methanol ration with the optimum yield was obtained at 1:12 at 78 °C with reaction time of 3 h. The reaction kinetics analysis was obtained including k = 2.50 x 10⁻⁴ min⁻¹, E_a = 73.43 kJ mol⁻¹ and the pre-exponential factor A = 19.22 min.⁻¹

In this article, we establish a new auxiliary identity on fractal sets for twice local differentiable function involving extended fractal integral operators. Testing this identity together with generalized fractal Hölder’s and Power-mean integral inequalities, we develop some new fractal–fractional Simpson’s type inequalities. Furthermore, we use modified Yang Hölder’s and Power-mean inequality to create new fractal estimates. We also give comparison analysis of bounds and show how the modified form of Yang Hölder’s and Power-mean integral inequalities can result in improved lower upper bounds. We also provide concrete examples to examine the validity of obtain results numerically and also justify them by 2D and 3D graphical analysis. As implementations, we operate our findings to get new applications in form of $\zeta$-type special means, moment of random variables and wave equations.

Broadband ferromagnetic resonance (BFMR) spectroscopy analysis can be achieved with different setups involving the frequency-sweep and field-sweep setups. To evaluate and compare the two former regimes, a frequency-sweep and a field-sweep shortcut BFMR regimes were conducted on Co–Ni ferrite nanoparticles that were synthesized by the co-precipitation method of metal chlorides. The nanoparticles were structurally and magnetically characterized, with an average particle size of around 23 nm and a spinel structure. The saturation magnetization was about 59 emu/g, and the coercivity was about 30 Oe. The BFMR analyses were achieved through a frequency range of (2–26) GHz and a field range of (0-10⁴)Oe. The two regimes, frequency sweep and field sweep, showed linear behavior between the resonance field and resonance frequency. The frequency–sweep regime displayed more complicated curves involving small multi-peaks within the multi-FMR absorption band that were not found in the field sweep regime. The intercepts of the linear dispersion relationship between the two regimes are nearly equivalent to each other. The field-sweep g-factor was higher and more reasonable than the frequency-sweep one, whereas its damping factor was lower. The fluctuation in the frequency linewidth vs. resonance field in the frequency-sweep method is higher than that for the field-sweep.

The present study uses the hydrothermal method to prepare nickel aluminum layered double hydroxide-functionalized humic acid and magnetite. Scanning electron microscopy, Fourier transfer infra-red, X-ray diffraction, N₂ adsorption-desorption isotherm, and vibrating sample magnetometer measurements are also used to determine the adsorbent's physicochemical properties. The mesopore-filling activity of Ni/Al functionalized humic acid and magnetite facilitates malachite green adsorption. Ni/Al functionalized humic acid and magnetite was collected from the water solution with a small additional magnet. Ni/Al and Ni/Al functionalized humic acid and magnetite exhibited type-IV sorption isotherms with the surface area of Ni/Al quadruples following functionalization with humic acid and magnetite. The pseudo-second-order kinetic and Langmuir isotherm adequately describe the adsorption process of the batch system. In the current case, the interaction of humic acid, magnetite, and the Ni/Al component may impact the leaching kinetics. Various factors, including pH, temperature, and competing ions, can impact the release of malachite green from the adsorbent surface. Malachite green has maximal Langmuir adsorption capacities of 68.966 mg/g and 178.571 mg/g on Ni/Al and Ni/Al-functionalized humic acid and magnetite, respectively. The result of the physisorption interaction processes was its efficient adsorption capacity for malachite green. This study offered recommendations on the development of adsorbents with high efficiency for the adsorption of malachite green.

In the face of escalating environmental challenges, the changes in land-use and land-cover (LULC) emerges as a persistent and significant threat, profoundly impacting the stability of eco-biodiversity. This study analyzes LULC changes using remote sensing techniques to detect environmental degradation in Abeokuta South, Nigeria, contributing to the discourse on environmental sustainability. LULC maps for the years 2002, 2012, and 2022 were generated, incorporating spectral environmental indicators such as land surface temperature (LST), normalized differential vegetation index (NDVI), and normalized difference built-up index (NDBI) from Landsat 7 and 8 satellite images. The support vector machine (SVM), and FRAGSTATS software, operating within the IDRISI and Arc-MAP environment, were employed to evaluate the area's LULC changes and land-use metrics. The findings revealed that built-up areas from 2000 to 2022 underwent the most significant changes, increasing by 39.52 km2 (55.85 %), while a noticeable decrease in vegetation cover trend by 27.95 km2 (36.45 %) was observed. Spatial land-use metrics, in conjunction with LST, NDVI, and NDBI, illustrated the quantitative and qualitative environmental changes in the area. Undeniably, the amalgamation of satellite remote-sensed data and spatial land-use metrics offers valuable tools to provide ecological information for urban sustainability. This study underscores the need for urgent attention from society, government, and stakeholders to manage population growth and balance human needs for a sustainable environment, thereby contributing to the broader goal of environmental sustainability.