Browsing by Author "Deniz E."

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Solar thermal waste heat energy recovery in solar distillation systems by using thermoelectric generators
(2023-04-01) Özcan Y.; Deniz E.
In this study, the novel use of thermoelectric technology in solar desalination systems was experimentally investigated. The new type of solar still with the thermoelectric generator (CSS-TEG) was proposed to improve the water output and efficiency. CSS-TEG's performance was assessed and compared with the conventional one (CSS). Economic and enviro-economic assessments, as well as energy and exergy analyses, were conducted based on the system parameters and measurements taken from the designed experimental setup. The new system's daily energy and exergy efficiency were obtained as 40.34% and 2.462% respectively, whereas, with the CSS one, they were 35.55% and 2.403%, respectively. The daily production of distilled water from the CSS and the newly designed solar still with TEG was measured at 4313 g/m2 and 4893 g/m2, respectively. In general, the estimated production cost of 1 kg of freshwater from CSS was 0.055$, and CSS-TEG was 0.081$. Additionally, referring to the exergo-economic parameter, CSS and CSS-TEG mitigated an average of 0.596 and 0.6132 tons of CO2 respectively.
The effect of pbse addition on the mechanical properties of Bi-2212 superconductors
(2012-10-01) Cavdar S.; Deniz E.; Koralay H.; Ozturk O.; Erdem M.; Gunen A.
The effects of PbSe addition and heat treatment on the structure and mechanical properties of Bi-2212 superconductors are analyzed. Glass ceramic method is used to produce PbSe added samples. The mechanical properties are derived using Vickers microhardness measurement results. Well known analysis methods like Meyer's law, PSR (Proportional Sample Resistance) Model, EDP (Elastic/ Plastic DeformationModel), Hays-Kendall approach and IIC (Indentation-Induced Cracking Model) are used to calculate load independent microhardness values of the samples. HK approach produces successful results for the samples A, E, F, G and H indicating ISE (Indentation Size Effect) behavior. The IIC model successfully explains RISE (Reverse Indentation Size Effect) behavior for the samples B, C and D. RISE behavior is observed only for the samples where the plastic deformation is dominant. ISE behavior is observed for the samples where both elastic and plastic deformation are produced. The results of XRD and SEM analysis show improvement with PbSe addition in the crystal structures and surface morphologies of superconducting samples. © Springer Science+Business Media, LLC 2012.
The Nucleation Effect of PbSe Additive on Bi2Sr2CaCu2Oδ Glass Ceramics
(2022-05-01) Çavdar Ş.; Deniz E.; Turan N.; Taşçı A.T.; Öztürk Ö.; Koralay H.
The crystallisation kinetics and effects of doping on Bi2Sr2CaCu2Oδ (BSCCO) glass ceramic system with 0.0%, 0.1%, 0.3% and 0.5% PbSe were investigated in this study. Differential thermal analysis (DTA) was used to investigate the effects of PbSe doping on glass transition, nucleation and crystallisation temperature of glass were investigated. The DTA results were analysed using the Ozawa, Augis–Bennett, Takhor and Kissinger equations for nucleation kinetics to determine the activation energies and Avrami parameters. Thermogravimetric analysis revealed that the amount of oxidation in the structure increased with increasing PbSe-doping concentration.