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Numerical investigation of melting of paraffin-wax phase change material in cone capsule with different alignments
No full textThe ability of phase change material to store thermal energy and how quickly the solid-liquid phase transition occurs depends on its thermal properties. The present numerical work focused on the melting of paraffin wax encapsulated in cone geometry using the Ansys fluent simulation tool. The cone capsule is 10 mm in size, has a base diameter, and has an axis height of 15 mm, with a vertical and horizontal orientation. The conservative mass, momentum, and energy equations are discretized and using the finite volume method are solved with a transient implicit method. The melting process of paraffin wax is captured with the help of the enthalpy-porosity equation with a mushy zone constant value of 104, while the PISO algorithm does pressure-velocity coupling. The transient temperature, mass fraction, temperature gradient per second, and mass fraction gradient per second of paraffin wax are plotted. From the results, it is observed that 100 % melting of PCM takes approximately 30 s and 36 s in the vertical and horizontal positions of the cone capsule, respectively. Further, it is also observed that the maximum drop in temperature gradient per unit of time is 19 % and 16 % in vertical and horizontal cone positions, respectively. Finally, it is concluded that the vertical cone provides improved heat transfer performance and uniform temperature distribution than the horizontal cone
A quantum chemical investigation of potential applicability of X12Y12 (X= B, Al, C; Y= N, P, C) nanocages for efficient removal of levofloxacin through water
No full textIn the last years, growing human populations and economies have led to increasing environmental pollution, especially in water. Due to the adverse effects of antibiotics in the water environment, public concerns have increased about the health issue. For this reason, removal of antibiotic pollutants from the water environment is urgently needed. This work has been conducted in order to find a suitable adsorbent nanocage structure from X12Y12 (B12N12, Al12N12, B12P12, Al12P12, C24) for removing levofloxacin antibiotic by using Density Functional Theory. The favorable adsorption processes are determined via adsorption energies and thermodynamic results for various orientations of levofloxacin onto the nanocages. The electronic nature of the adsorption processes is investigated with the help of Mulliken analysis, Natural Bond Orbital Analysis, and Quantum Theory of Atoms in Molecules. The reactivity and sensitivity investigation of the nanocage and levofloxacin complex systems is elucidated with global reactivity indices, Frontier Molecular Orbitals, Density of States spectra, and work function. The change of dipole moment values after adsorption are determined. The spontaneous characters of adsorption processes are determined. Furthermore, the number of LEV molecules, the water medium and the saline content of water effects the adsorption of LEV have been determined. The outcomes of this study demonstrate that Al12N12 and Al12P12 nanocages can be useable for effective removal of levofloxacin. The results of this study will be a novel contribution for further studies in order to remove levofloxacin effectively
An Innovative Multidisciplinary Strategy for Improving Students Capacity for Computational Thinking: The Harezmi Education Model
No full textKENT KİMLİĞİNİ YANSITACAK VE İKLİM DEĞİŞİKLİĞİNE UYUM SAĞLAYABİLECEK ODUNSU BİTKİLER: DÜZCE
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Al2O3 pellet supported transition metal oxide catalysts for H2 generation from alkaline NaBH4 solution
No full textYoung Adults’ Place Attachment and Community Dependence: Exploring the Differences Between Rural and Urban Communities
No full textGraphene-based additives in NiOx layers for better charge transport
No full textThe low conductivity of nickel oxide hole transporters is the main disadvantage to getting superior power conversion efficiencies for planar p-i-n type perovskite solar cells. This study aims to enhance the conductivity of conventional nickel oxide layers by incorporating graphene additives. Graphene nanoplatelets (GNP) and Thermally Exfoliated Graphene Oxide (TEGO) were directly introduced to the nickel oxide layer in the step of precursor preparation. Entire solar cell fabrication with a configuration of ITO/NiOx/CH3NH3PbI3/PCBM/BCP/Ag was conducted in ambient air through sol–gel processes without a glove box. Results revealed increased short-circuit current densities and open-circuit voltages with the graphene additives, and TEGO performed slightly better than GNP, giving a ~ 15% increase in power conversion efficiencies. This enhancement was scrutinized and confirmed through a series of experiments, including X-ray diffraction, UV–visible spectrophotometry, field-emission scanning electron microscopy, Kelvin Probe microscopy, and electrical measurements. Graphene additives were found to increase the work function from 5.18 eV to 5.21 eV. Hence, combined with increased electrical conductivity, one can conclude a clear increment in charge extraction with a lowered recombination loss, which suggests solar cell performance. The conductivity of NiOx increased by 57.0% and 103.7% for GNP- and TEGO-modified films, respectively, while the work function slightly increased by 0.58% (GNP) and 0.39% (TEGO). XRD and FESEM analyses confirmed enlarged perovskite grain sizes, particularly in the GNP-based devices. These improvements resulted in enhanced device performance: the average short-circuit current density increased from 18.0 mA/cm2 to 22.7 mA/cm2 (GNP) and 22.1 mA/cm2 (TEGO), open-circuit voltages increased from 1018 to 1034 mV (GNP) and 1036 mV (TEGO), and the fill factor increased from 62.1% to 64.6% (GNP) and 65.5% (TEGO). Consequently, the average PCE increased from 11.6% to 15.2% (GNP) and 15.0% (TEGO), with champion open-circuit voltage values reaching 1082 mV. The hysteresis factor was also greatly reduced to 0.012 (GNP) and 0.018 (TEGO), compared to 0.13 for pristine NiOx. Long-term stability tests demonstrated that after 96 h, TEGO- and GNP-modified devices retained 98% and 96% of their initial PCE, while the reference dropped to 76%. After 350 h, GNP and TEGO retained 95% and 81%, respectively, while the reference fell to 62%. These trends correlate with lower VTFL values from SCLC curves, indicating reduced trap densities, calculated as 3.38 1016 cm−3, 3.40 1016 cm−3, and 3.81 1016 cm−3 for GNP, TEGO, and reference HTL, respectively, employed hole-only devices, respectively
