Water scarcity is developing in the Middle East as a result of the region's growing population and tremendously advanced agricultural and industrial sectors. Saudi Arabia is the Middle East country with the highest water consumption, so there is an urgent need to take action, and new technology advancements in geophysical measurements allow for the monitoring of groundwater. Wadi Ar-Ramah is one region that has witnessed significant agricultural expansion as well as a serious over-exploitation of the groundwater resources that are available there. Depletion rate in groundwater of the Wadi Ar-Ramah basin at eastern Saudi Arabia was determined for the time interval of 04/2002 to 12/2021 using a combination of gravity data from the Gravity Recovery and Climate Experiment (GRACE) mission and results of land surface models. The findings are: (1) the average yearly rainfall rate was computed at 87.7 mm yr -1 over the Wadi Ar-Ramah; (2) the terrestrial water storage variation (ΔTWS) was computed at -1.216±0.013 cm yr -1 ; (3) the GLDAS-derived soil moisture (ΔSMS) was minimal at -0.32±0.025 mm yr -1 ; (4) the GRACE-derievd groundwater decreasing rate was calculated at 1.212±0.012 cm yr -1 ; (5) the relief of the ground surface is producing northeasterly streams that carry the minimal surface water to the east; (6) our integrated method provides a repeatable and cost-effective approach

The numerous hydrothermal alteration zones and subsurface structures affecting the mineralized deposits
of the Dungash region were identified using aeromagnetic data. The Center of Exploration Targeting
(CET) approach and several filters, such as reduction-to-pole, Tilt derivative, First Vertical Derivative,
Horizontal gradient map, Downward continuation, analytical signal methods, regional, and residual separation,
were used to analyze the aeromagnetic data. The research region is impacted by several structural
trends running in the N-S, E-W, NW-SE, and NE-SW directions, and these trends are strongly
related to the gold mineralization and surrounding hydrothermal alteration zones. In the NW-SE direction,
four alteration zones have been identified. The research region’s northern and eastern regions have
shallower basement relief, with depths of only approximately 100 m, and those depths show that the
area is rootless. Conversely, the basement relief and surface depths are lower in the study region’s western
and southern regions. The routes taken by the ascending hydrothermal fluids can be seen as aeromagnetic
lineaments at the hydrothermal alteration zones. Mineralization appears to be linked to structural
lineaments, as evidenced by airborne magnetic data. For gold prospecting, the aeromagnetic technique
seems to be the most effective and efficient geophysical method because gold is typically found in
severely deformed shear zones and faults.

Herein, PbI₂ nanostructured thin films were grown on glass substrates with different (0.5, 1.0 and 1.5 g) solute concentrations using a spin coating technique. The impact of the solute concentration on the structural, optical, nonlinear optical properties was examined thoroughly and was analyzed as a function of solute concentrations. The X-ray diffraction (XRD) patterns of the films confirm a hexagonal wurtzite structure with a preferred orientation along (001) plane. The band gap of the films was calculated using absorbance spectra and found to be about 2.41–2.56 eV. The refractive index (n), extinction coefficient (k), optical dielectric constant, SELF and VELF were investigated and analyzed. In addition, third order optical susceptibility (χ⁽³⁾), nonlinear refractive index (n₂) were also calculated. The obtained data shows that the prepared films are promising for optoelectronics applications.

Fluorotellurite glass codoped with erbium and ytterbium was elaborated through the melting-quenching route. Through the DSC and Raman measurements, the investigated glass samples presented high thermal stability and low phonon energy, respectively. By using the laser excitation at 488 nm, the downconversion mechanism in the Er³⁺/Yb³⁺ system was investigated and the energy transfers implicated in the emissions of erbium and ytterbium ions were discussed based on the different cross-relaxation processes. The addition of ytterbium resulted in an effective energy transfer from the excited ⁴S_3/2/²H_11/2 state of Er³⁺ ions to the emitting ²F_5/2 state of Yb³⁺ ion, which considerably enhanced NIR emissions at 1000 nm and reduced experimental lifetimes of  ⁴S_3/2/²H_11/2 states. Through luminescence decay analysis, the maximum values of quantum efficiency (η_QE) and energy transfer efficiency (η_ET) were estimated as 61.2% and 161.2%, respectively. This result indicates that the proposed glasses can convert visible photons into NIR emissions at 1000 nm suitable to improve the spectral response of crystalline silicon PV cells.

The size and density of nanopits, generated at the surface of their top layer, strongly affect the electrical and optical properties of AlGaN-based structures. Therefore, the control of the layer quality evolution as a function of the nanopits size/density is a crucial issue to enhance the device performance. In this paper, the effects of the nanopits diameter observed at the surface of AlGaN on carrier dynamics are systematically investigated. The variation of nanopits diam-eter is achieved through thermal annealing of a set of AlGaN/GaN heterostructures at different temperatures. The samples are characterized using the scanning electron microscope (SEM), energy-dispersive x-ray, high-resolution x-ray diffraction, photoluminescence (PL), and time-resolved PL spectroscopies. SEM images have revealed an increase in the nanopits diameter with increasing annealing temperature. In addition, we observed a linear development in the yellow luminescence intensity, accompanied by a deterioration in the PL decay times due to an increase in the density of point-defect complexes that act as nonradiative recombination centers. We also performed temperature-dependent PL measurements to study the impact of the nanopits diameter on electron–phonon scattering processes. Both electron-acoustic- and electron-longitudinal optical phonon interactions enhance with increasing nanopits diameter.

Copper indium sulfide (CIS), zinc sulfide (ZnS) and CIS/ZnS nano-adsorbents (NAs) encapsulated with mercaptopropionic acid (MPA) were synthesized and characterized with different techniques, and finally tested for the adsorption/photodegradation of methyl blue dye (MB) in aqueous solution under UV irradiation. Structural and optical properties of the nanocrystals were determined via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopic, UV–Visible and photoluminescence spectroscopy. CIS/ZnS showed a specific surface area of 24.06 cm² g⁻¹ and an adsorption capacity of 27.71 mg g⁻¹ for MB. MB adsorption kinetic was found to follow the pseudo-second order kinetic model and the Langmuir-Freundlich model was the best model to describe the adsorption isotherms. Taking into account the statistical physics analysis and the theoretical meaning of the parameters, the Hill model with one activation energy presented the best prediction of the experimental data, indicating that MB dye adsorption occurred by the formation of a monolayer and that MB interaction with CIS/ZnS were characterized by only one activation energy. The calculated adsorption energy varied from 19.38 to 20.04 kJ mol⁻¹ suggesting that the adsorption occurred via physical interactions via a multimolecular adsorption process. The photodegradation activity of the core–shell NAs under UV irradiation showed better efficiency than the bare core and Shell NAs thus indicating that ZnS recovery improved the degradation power of the CIS nano-adsorbents (97 %). In summary, these eco-friendly NAs are highly promising materials for efficient wastewater treatment to face water pollution caused by organic compounds via adsorption and photodegradation processes.

We report the microstructure, optical properties and high photocatalytic performance, with correlations between them, of coprecipitated and post-annealed ZnO nanoparticles. The obtained ZnO single phase after post annealing at different temperatures (200–600 °C) was identified by X-ray diffraction (XRD) and its morphology was investigated by transmission electron microscopy (TEM). The TEM results indicate a gradual growth of the spherical-like nanoparticles to nanorod-like shapes by post annealing with common nanorods shape by annealing at 600 °C. XRD Rietveld refinements indicated that the global structure parameters such as lattice constants, bond lengths, and oxygen position are slightly affected by the post annealing. While the crystallite size and number of unit cells per a particle gradually increase, the dislocation density, micro-strain and residual stress gradually decrease by the post annealing with a further change at annealing temperature of 500 °C, indicating correlations to the particles shape. Based on optical absorbance measurements, it was found that the optical energy gap gradually decreases from 3.22 to 2.89 eV by increasing the annealing temperature up to 600 °C. After a period up to 90 min of irradiation, photo-catalytic efficiency of up to 95 % was observed in the photo-degradation of methylene blue. In addition, the nanoparticles annealed at low temperature showed better performance in the photo-degradation of methylene blue. The observed high photocatalytic performance is discussed in correlation to the microstructure and optical properties of the investigated samples.

Sol-gel spin coating technique was used to develop Zn and Ag co-doped CdO thin films with 3.0 wt% Zn and various Ag doping concentrations. A cubic structure and a preferred orientation along (111) growth plane of samples was confirmed from films diffractograms analysis. The crystallites sizes of the samples were calculated and found about ∼33–44 nm. A further investigation of the structural phase of the films was carried out using Raman spectroscopy. The elemental composition of the films was examined using EDX technique which confirmed the presence of all elements. The collected EDX mapping spectra revealed a successful Zn and Ag co-doping of CdO films with a uniform elemental distribution. A controlled tailoring of the optical band gap of the film was achieved via Zn and Ag co-doping of CdO films. The band gaps of films were obtained from the Uv–vis absorbance spectra and were found to be in the order ∼1.87–2.32 eV. A significant improvement in nonlinear optical parameters was observed for the Zn doped CdO matrix with high Ag doping concentrations where χ⁽³⁾ was estimated to be about 5.52 × 10⁻¹²-4.16 × 10⁻¹² esu and (n₂) ∼1.84 × 10⁻¹¹-1.51 × 10⁻¹⁰ esu; respectively. On the other hand, Hall measurements of the grown films revealed interesting improvements in the carrier concentrations and conductivity. Films I–V characteristics show an ohmic contact with enhanced conducting behavior which suggests that the developed co-doped CdO films are promising for optoelectronics applications.