https://hdl.handle.net/20.500.12960/33 Mon, 11 May 2026 14:15:05 GMT 2026-05-11T14:15:05Z https://hdl.handle.net/20.500.12960/1822 Comprehensive first-principles studies of structural, dynamical, elastic, electronic, thermoelectric, and thermodynamic properties of Half-Heusler TiGaAu compound Belbachir, Raghed; Belkharroubi, Fadila; Al-Douri Y.; Sidjilani, Fatima; Khelfaoui, Friha; Azzi, Saliha; Belmiloud, Nawal; Rahmani, Rabea; El Hadj, Adel Abdellah; Bendella, Sid Ahmed The structural, elastic, electronic, dynamical, thermoelectric (TE), and thermodynamic properties of Half-Heusler (HH) TiGaAu compound with valence electron count (VEC) of 8, are investigated usingfirst-principles density functional theory (DFT) in conjunction with Boltz- TraP2 transport modeling. The Type 1 nonmagnetic phase's optimized cubic structure meets the Born mechanical stability requirements and its dynamical stability, which is confirmed by the phonon dispersion's lack of imaginary frequencies. Due to the presence of a heavy Au atom, TiGaAu exhibits pronounced elastic anisotropy and is mechanically strong, stiff, and ductile according to elastic constants. With a moderate band gap, 0.681 eV (mBJ-GGA), the electronic band structure favors balanced electron{hole transport and reveals an indirect semiconductor character. Thermoelectric analysis reveals that TiGaAu has competitive values up to 900K and high Seebeck coeffcients exceeding 1000 μVK-1 at room temperature, with p-type carriers performing marginally better. Effective carrier transport and advantageous band convergence are reflected in the power factor's steady temperature increase. Though mBJ-GGA predicts somewhat higher Seebeck and power factor values at higher temperatures - an improvement ascribed to its more accurate description of electronic structure - the results obtained using GGA and mBJ-GGA are consistent across the whole range. Furthermore, an excellent thermal stability and moderate lattice softening are confirmed by the smooth variation of temperatureand pressure-dependent thermodynamic properties, including heat capacities, entropy, thermal expansion coeffcient, Debye temperature and Grüneisen parameter. TiGaAu is a promising option for high-temperature energy conversion applications as it combines a strong mechanical resilience, stable lattice dynamics and effcient thermoelectric behavior. Thu, 01 Jan 2026 00:00:00 GMT https://hdl.handle.net/20.500.12960/1822 2026-01-01T00:00:00Z https://hdl.handle.net/20.500.12960/1813 Levy flight-assisted hybrid Sine-Cosine Aquila optimizer for solving chemical equilibrium problems through the Gibbs free energy minimization technique Turgut, Oğuz Emrah; Genceli, Hadi; Asker, Mustafa; Baniasadi, Ehsan; Çoban, Mustafa Turhan This research proposes a novel hybrid metaheuristic optimization framework that combines the Aquila Optimization algorithm with the Sine-Cosine Optimizer to find equilibrium points of reacting components under specified operational reaction conditions. The method aims to address the exploitative limitations of the standard Aquila algorithm by incorporating oscillatory sine-cosine movements into the hybrid optimizer, which is one of the significant drawbacks of the base Aquila algorithm that should be addressed. The effectiveness of the hybrid approach is thoroughly tested on a suite of 100 multidimensional unimodal and multimodal benchmark cases, with results compared to those from well-known literature optimizers. Additionally, twenty-eight 30-dimensional benchmark functions from the 2013 Congress on Evolutionary Computation competition are used to evaluate the prediction performance. Three multidimensional constrained engineering design problems are also solved, and their results are compared with those from other literature optimizers. The findings show that the hybrid algorithm produces the best estimates and ranks first among competing algorithms based on average ranking results. To further verify its robustness and accuracy, three more complex chemical equilibrium problems are solved using the Gibbs Free Energy minimization method. The predictions are benchmarked against recent metaheuristic algorithms for each case, demonstrating that the proposed hybrid effectively overcomes the challenges of highly nonlinear and non-convex free energy surfaces, achieving higher solution consistency while finding minimum objective function values across different chemical equilibrium scenarios. Wed, 01 Jan 2025 00:00:00 GMT https://hdl.handle.net/20.500.12960/1813 2025-01-01T00:00:00Z https://hdl.handle.net/20.500.12960/1793 First-principles studies on structural, elastic, electronic, optical, thermodynamic and thermoelectric properties of RbScC and CsScC half-Heusler alloys Sidjilani, Fatima; Belkharroubi, Fadila; Al-Douri Y.; Hamdache, Fatima; Bahlouli, Samia; Bendella, Sid Ahmed; Sediki, Hayat; Khelfaoui, Friha; Dib, Anis Samy Amine; Belkaid, Mohammed Noureddine; Al-Samarai, Riyadh A. The semi-classical Boltzmann transport theory under the constant relaxation time approximation, combined with density functional theory (DFT) calculations performed using the WIEN2k code are utilized to investigate the elastic, structural, optoelectronic, and thermoelectric properties of XScC (X = Rb, Cs) half-Heusler alloys. Our study reveals that RbScC and CsScC half-Heusler alloys are both thermodynamically stable, as shown by their negative formation energies—an encouraging sign for their possible experimental realization. To gain deeper insight into their mechanical behavior, we have explored how their elastic constants respond to applied pressure from 0 to 25 GPa. The results show smooth, positive trend, indicating strong interatomic forces and robust mechanical stability under compression. Both RbScC and CsScC half-Heusler alloys are classified as semiconductors. RbScC has a direct X → X bandgap and CsScC displays an indirect Γ → X bandgap. Moreover, these systems exhibit semiconducting properties marked by a flat band next to the Fermi energy (EF), rendering them viable candidates for thermoelectric applications. The RbScC and CsScC alloys have minimal reflectivity and absorptivity in the ultraviolet spectrum and significant absorption in IR. Investigations are achieved on the Seebeck coefficient, figure of merit (ZT), power factor, electrical conductivity, and electronic thermal conductivity in relation to the temperature and chemical potential. RbScC and CsScC have a high power factor for p-type doping. At ambient temperature, it is found that high Seebeck coefficients are 245.36 µV/K for RbScC and 244.06 µV/K for CsScC, with a figure of merit nearing unity. Our results show that these alloys have the potential to be thermoelectric materials. Furthermore, the thermodynamic parameters of XScC (X = Rb, Cs) half-Heusler alloys at various pressures, 0–25 GPa and temperatures 0–900 K are determined by utilizing the quasi-harmonic Debye model. https://hdl.handle.net/20.500.12960/1793 https://hdl.handle.net/20.500.12960/1790 Nanostructured Magnesium Oxide for Swiss Mice Tissue Application: Synthesis, Characterization, and Analysis Al-Douri, Asaad T.; Salman, Safa salah; Al-Doori, Maksood Adil Mahmoud; Mahmood, Israa Adil; Khalaf, Ahmed M.; Ibrahim, Mustafa Khaleel; Khalaf, Zina Edress; El-Tekreti, Sama Amer Abbas; Al-Douri, Yarub; Ameri, Mohammed Rosemary extract produced nanoscale magnesium oxide (MgO) using a green synthesis methodology, specifically a chemical co-precipitation process. This work investigates the effects of nanoscale MgO on Swiss mice. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) are used to characterize the synthesized material. Nano-MgO is administered orally to mice, and then the liver and kidney tissues are examined histologically to evaluate its biological effects. The results demonstrated the remarkable biological activity of nanoscale MgO, revealing a clear inhibitory effect on these organs. According to the findings, nanoscale MgO may be useful and suitable for biomedical applications, especially for targeted inhibition in kidney and liver tissues without causing serious toxicity risks. https://hdl.handle.net/20.500.12960/1790