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• Alternatif Enerji Kaynakları Teknolojisi Programı
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Araştırmacılar(10)

• Alım, Bünyamin
• Çınar, Mehmet
• Çorapsiz, Muhammed Reşit
• Güngör, Osman
• Kaya, Yunus
• Kosunalp, Selahattin
• Teber, Ahmet
• Tekin, Sinan
• Tozlu, Alperen
• Yarımkaya, Derya

• MakaleAçık Erişim2026Scopus SJRQ1/r/bayburt/11526
  Determination of complex permittivity of a thin low-loss dielectric sample using state-space approach from waveguide measurements

  Hasar, Ugur C.; Ali, Husain; Kaya, Yunus

  An extraction procedure is proposed for relative complex permittivity () determination of thin low-loss samples positioned/deposited on a supporting substrate material using waveguide non-resonant microwave measurements. Its substrate thickness and sample thickness independence makes it unique extraction method in comparison with the available retrieval methods which are free from either substrate thickness information only or sample thickness information only. Its theoretical model is constructed on the state-transition matrix and state vector through which the link between and measured scattering (S-) parameters is established. Compared with previous works in the literature, a closed form (explicit) expression of is derived for a two-layer (sample on a substrate material) composite structure, thereby eliminating any numerical analysis or tool. Numerical analyses are implemented for validation of the proposed method as well as assessing the effect of noise and any possible air gap between the sample and its substrate. X-band ( GHz) waveguide measurements of a thinner (around 1.00 mm) polyvinyl chloride (PVC) for different measurement scenarios and measurements of a thin zinc oxide film (m) were performed to evaluate the performance of the proposed extraction method against other similar methods in the literature. Our method can find applications for characterization of thin-film, radar-absorbent material coatings, anti-corrosive paints, or thermal barrier coatings where sample thickness (and substrate thickness) can vary from one sample to another from the same batch.

  İncele
• MakaleAçık Erişim2026Scopus SJRQ3/r/bayburt/11354
  Molecular structure, spectral characteristics, and nonlinear optical properties of labetalol: an experimental and computational investigation

  Çınar, Mehmet; Can, Sümeyra

  Labetalol is an antihypertensive agent that possesses both α- and β-adrenergic blocking properties. This characteristic allows for its clinical use in both chronic hypertension and hypertensive emergencies. In this study, the FT-IR, FT-Raman, 1 H, 13 C, and DEPT-135 NMR spectra of labetalol hydrochloride (Labetalol HCl) were recorded and examined. Furthermore, the pharmacologically active (R, R) stereoisomer of labetalol was theoretically investigated using the B3LYP functional and the 6-311++G(d, p) basis set. The theoretically determined ground-state geometry of the molecule showed excellent agreement with experimental data reported in the literature. Using the obtained optimized structure, the vibrational spectra of the molecule were simulated, and the vibrational modes were assigned by evaluating them together with the experimental data. Nuclear Magnetic Resonance (NMR) analysis of the molecule was performed considering experimentally recorded values and calculations for gas phase, DMSO, and chloroform solvent environments, and the chemical shift values for each H and C atom were determined. Using Time-Dependent Density Functional Theory (TD-DFT) and Solvation Model based on Density (SMD) approaches, the UV-Vis spectra of the molecule were obtained in the gas phase and in four different solvent environments (ethanol, methanol, DMSO, and water). To better understand the electronic properties of the molecule, Frontier Molecular Orbitals (FMO), Molecular Electrostatic Potential Surface (MEPS), Hirshfeld surface analysis, Mulliken and Hirshfeld charge distributions, and Density States (DoS) analyses were performed. In addition, the non-linear optical (NLO) properties of the molecule were theoretically calculated, and the results showed that the molecule could be a promising NLO candidate.

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• MakaleAçık Erişim2026Scopus SJRQ1/r/bayburt/11083
  A comparative study of metaheuristic algorithms for thermoeconomic optimization of an Organic Rankine Cycle

  Tayfur, Bilal; Turhal, Uğur; Tozlu, Alperen

  The efficient recovery of waste heat from biogas power plants via Organic Rankine Cycles (ORC) is essential for sustainable energy but requires satisfying conflicting thermodynamic and economic objectives. This study addresses the need for robust optimization strategies by evaluating nine recent metaheuristic algorithms to identify the most effective methods for maximizing net power while minimizing system costs. A multi-objective thermoeconomic model utilizing the specific exergy costing method was developed for a toluene-based ORC and optimized using algorithms including Dung Beetle, Snake, and NSGA-II. The optimization reduced the unit electricity cost by 9.1% (from $0.088/kWh to $0.080/kWh), with the Dung Beetle algorithm exhibiting superior convergence (Hypervolume 25.90) and the Snake algorithm demonstrating the best solution uniformity (Spread 1.54) with computational speed (0.084 s). These findings underscore that selecting algorithms based on specific exploration-exploitation characteristics is critical for achieving cost-effective and thermodynamically efficient power generation designs.

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  AtıfOpenAlex2

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• Derleme MakaleAçık Erişim2026/r/bayburt/10990
  Environmental and economic analysis of industrial waste heat recovery with hybrid heat pump application

  Kazici, Halil İbrahim; Tozlu, Alperen

  Today, increasing energy demands and environmental concerns have made energy efficiency a necessity from both economic and ecological perspectives. High energy consumption in industrial facilities increases costs and raises CO2 emissions. Therefore, waste heat recovery and the use of renewable energy are among the fundamental goals of sustainable production. Energy efficiency is important not only for reducing consumption but also for lowering greenhouse gas emissions, protecting the environment, and strengthening the economics of the business. In this context, heat pump technologies, which extract energy from low-temperature sources and make it reusable, stand out as effective, environmentally friendly, and efficient systems in both heating and cooling applications. In this study, waste heat from a cooling tower generated during the production process in an industrial facility was recovered through a water-source heat pump and integrated into the facility's heating system. The heat pump increased the heat energy by using low-temperature water and reused it in the process. During periods when the waste heat was insufficient, the system was supported by natural gas boilers, thus creating a hybrid operating model between the heat pump and the boiler. As a result of the implementation, natural gas consumption and electricity usage were significantly reduced, leading to lower energy costs and a substantial decrease in CO2 emissions, thereby providing notable environmental benefits. The findings indicate that the proposed system achieves an annual natural gas saving of 6,788,251 kWh and a net financial gain of 5,703,864 TL. Additionally, the payback period of the investment is calculated as 2.41 years, demonstrating the economic feasibility of the system. Overall, this case study highlights that the widespread adoption of hybrid heat pump systems in the industrial sector can make significant contributions to Türkiye’s energy transition and carbon emission goals.

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• MakaleYalnız künye2026Scopus SJRQ3/r/bayburt/10916
  An exergoeconomic analysis of a wastewater treatment plant: investigation and optimization of sludge drying—a case study

  Dagci, O.; Tozlu, A.; Berber, A.

  The primary parameters in wastewater treatment plant applications are pollutant removal in compliance with standards and energy costs. This study conducts exergy, exergoeconomic, and optimization analyses on the Konya Wastewater Treatment Plant to enhance its energy efficiency. All assessments of the plant were based on actual operational data. Numerical calculations were executed using Engineering Equation Solver software. Exergoeconomic analyses were performed using the Specific Cost Method, while optimization calculations employed the Net Present Value approach. Thermodynamic calculations revealed that the exergy efficiency of the biogas engine was 30.8%, which increased to 39.8% when integrated into a cogeneration system. The overall exergy efficiency of the plant was calculated to be 35.3%, which rose to 58.6% when stabilized sludge was utilized as fuel. During the optimization phase, various drying systems were evaluated, and a hybrid greenhouse-solar-panel drying system was identified as the optimal model. The analyses indicated that the total cost was minimized at the maximum dryness value (70%), suggesting that the greenhouse-type drying system could achieve regional conditions. Compared to thermal and solar energy systems, hybrid systems have been observed to offer significant advantages in first-year costs. Optimization studies reveal that hybrid systems provide 41% greater cost savings in initial investment and operational expenses compared to thermal systems, and 29% greater savings compared to solar energy systems. Meeting the system's energy demand with fossil fuels results in annual emissions of 76,850 tons of CO₂ and 1500 tons of harmful pollutants, equivalent to removing 19,000 cars from traffic or preserving 7300 hectares of forest. Significant soil and ecosystem degradation also occurs. The use of solar energy substantially reduces these environmental impacts, improving air quality and conserving natural resources.

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  AtıfScopus1·OpenAlex1

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• MakaleAçık Erişim2025Scopus SJRQ1/r/bayburt/14346
  Energy, exergy and economic optimization application of integrated dual-loop organic rankine cycle: A case of shopping mall power plant

  Topcu, Muhammed Taha; Tozlu, Alperen; Bilen, Kadir

  This paper presents a thermoeconomic analysis of the Dual-Loop Organic Rankine Cycle (DORC) integrated into the Erzurum Mall Power Plant (EMPP). The DORC system is designed to utilize waste heat at 425 degrees C and 9 kg/s, producing additional power for the existing plant. The integration of dual-loop ORC systems with different critical temperature fluids into an operational facility is analyzed. High-temperature cycles use working fluids such as Toluene, MDM (octamethylcyclotrisiloxane), n-Nonane, and n-Octane, while refrigerants R236fa, R600a, and R124 are employed in the low-temperature cycles. The designed model demonstrates that up to 11.4 % of the plant's existing capacity can be added as extra power. The Toluene/R600a combination is identified as the best fluid pair, delivering the highest total net power output (653.4 kW), the lowest total cost rate (19.18 $/h), and the highest exergy efficiency (20.18 %). Optimization of the DORC system is performed using the NSGA-II in MATLAB. For the toluene/R600a pair, the optimization results show an increase of 13.52 % in the net power output and decrease of 1.48 % in the total cost rate, which is a significant improvement over the initial results.

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  AtıfWoS3·OpenAlex1

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• MakaleYalnız künye2025Scopus SJRQ1/r/bayburt/10751
  Tailoring the Electron Density of Functional Groups for Controlled Charge Transfer in SWCNTs

  Fiebor, Alphonse; Cinar, Mehmet; Amsalem, Patrick; Achazi, Andreas J.; Gordeev, Georgy; Bartonitz, Florian; Xin, Fan; Koch, Norbert; Adeli, Mohsen; Paulus, Beate

  Controlling the position of the Fermi level at the single-particle level in bulk amount of carbon nanotubes is a key technological bottleneck against their use in building nanodevices for electronics, optics, sensing, bioimaging, and beyond. Here are deployed a novel set of molecules built up from the same building blocks (aniline and methoxy groups attached on a triazine anchor) that efficiently p- and n-dope the nanotubes, depending upon the way they are assembled. Independent computational and experimental investigations consistently confirm the tunability-by-assembly concept of the charge transfer agents. The changes of the electronic density localized on the anchor groups and, upon attachment, the consistent variation of the position of the Fermi level in single-walled carbon nanotubes are monitored. The induced shifts reach several hundreds of meV, ranging from p-doping up to n-doping. This is evidenced by changes in the electronic and vibrational behavior of the nanotubes, as observed by Raman, photoelectron, and photoluminescence spectroscopies.

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• MakaleYalnız künye2025Scopus SJRQ4/r/bayburt/11530
  Tunable optoelectronic performance of ZnO-Coated TiO2 nanowires for enhanced UV photodetection

  Sarac, M.F.; Solakyildirim, T.; Teber, A.

  In this study, vertically aligned TiO2 nanowires (NWs) were fabricated on titanium (Ti) foil via thermal oxidation and subsequently coated with zinc oxide (ZnO) using zinc acetate solutions of 25, 50, and 100 mM concentrations. Structural and optoelectronic properties were systematically investigated using SEM, XRD, XPS, PL, UV-Vis, and I-V analyses. SEM results confirmed a progressive ZnO surface coverage, with complete encapsulation observed at 100 mM. EDS analysis revealed a Zn content increase from 0.81 wt.% (25 mM) to 8.43 wt.% (100 mM), accompanied by a decrease in Ti content from 70.78 wt.% to 49.02 wt.%. XRD patterns showed distinct ZnO peaks for coated samples, while XPS confirmed Zn2+ and Ti4+ states with minimal interdiffusion. Optical bandgap values increased slightly with ZnO concentration: 3.04 eV (pure TiO2), 3.06 eV (25 mM), 3.05 eV (50 mM), and 3.11 eV (100 mM), attributed to enhanced crystallinity and heterojunction formation. PL spectra showed increasing green luminescence (∼520 nm) with ZnO content, indicating rising defect-related recombination. Electrical measurements showed a sharp rise in photocurrent from 3.67 × 10−6 A (pure TiO2) to 4.74 × 10−4 A (100 mM). Correspondingly, responsivity (R) increased from 0.020 to 2.168 mA/W and detectivity (D*) from 8.5 × 108to 7.56 × 109 Jones. These results demonstrate that ZnO coating substantially enhances light absorption, charge separation, and carrier transport properties of TiO2 NWs. The optimized 100 mM ZnO-TiO2 heterostructure offers high-performance UV photodetection potential for environmental sensing, wearable optoelectronics, and aerospace technologies.

  AtıfOpenAlex1

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11519
  Detailed investigation of the spectroscopic features of nicardipine hydrochloride using experimental and quantum chemical methods

  Can, Sumeyra; Cinar, Mehmet; Baris, Ozlem

  Context: The structural and spectroscopic properties of drug groups can be determined using spectroscopic techniques and quantum chemical calculations. In this study, the structural and spectroscopic properties of nicardipine, a potent calcium channel blocker belonging to the dihydropyridine drug group, were investigated. For this purpose, FT-IR, Raman, NMR, and UV–Vis spectra of nicardipine hydrochloride were recorded. The ground state geometry optimization performed under vacuum conditions showed excellent agreement with X-ray diffraction (XRD) data, with root-mean-square deviations of bond lengths and bond angles calculated as 0.017 Å and 2.2°, respectively. Vibrational spectrum analysis revealed all characteristic modes, and theoretical B3LYP predictions largely agreed with experimental data. NMR spectra recorded in chloroform solvent confirmed the molecular structure of nicardipine. A comparison with previously reported data revealed significant differences in the proton NMR results, while the carbon NMR data showed consistency. The gauge-invariant atomic orbital (GIAO) method, commonly used for NMR spectrum prediction, yielded results within an acceptable error range despite minor inconsistencies arising from differences between experimental and computational conditions. In the UV–Vis spectrum of nicardipine HCl, an absorption peak corresponding to π-π* excitation was observed at 238 nm. Method: The geometric optimizations and vibration spectra of the nicardipine drug molecule were performed using the Gaussian 09 program with the B3LYP functional and the 6–311 + + G(d,p) basis set. Visualizations were performed using the GaussView 5.0 interface program. NMR spectra were recorded in chloroform solvent using the GIAO method. Molecular electrostatic potential (MEP) maps and Mulliken atomic charges were analyzed to gain deeper insight into the electronic properties.

  AtıfScopus1·WoS1·OpenAlex1

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• MakaleAçık Erişim2025Scopus SJRQ2/r/bayburt/11246
  High-Performance Microwave-Absorbing Hemp Textile: Ni-Zn Ferrite and Multiwalled Carbon Nanotubes-Infused Nanocomposite for X-Band Electromagnetic Interference Shielding

  Teber, Pembe; Teber, Ahmet; Karakaş, İbrahim Hakkı

  This study aims to develop a flexible and sustainable electromagnetic (EM) wave-absorbing material by using hemp fabric as a substrate incorporated with multiwalled carbon nanotubes (MWCNTs) and magnetic Ni-Zn ferrite nanoparticles (NPs). In this context, the objective is to achieve effective EM attenuation across a wide frequency range using a green, lightweight composite to meet the rising demand for ecofriendly shielding in electronic and communication systems. Ni0.5Zn0.5Fe2O4 and MWCNT composite NPs are uniformly dispersed in a molten paraffin binder and impregnated into hemp fabrics. The magnetic NPs are synthesized via the microwave-assisted combustion method. The EM parameters of the resulting structure are determined in the X-band using experimental scattering data and the Nicholson–Ross–Weir method. Absorption performance is evaluated based on varying weight ratios of magnetic NPs and MWCNTs, with an emphasis on impedance matching. The results indicate that combining dielectric and magnetic components significantly enhances absorption. A maximum reflection loss of −72.42 dB and a 3.81 GHz bandwidth (covering over 90.71% of the X-band) are achieved at 10.08 GHz. Increasing Ni-Zn content shifts the resonance to higher frequencies. This sustainable, flexible composite shows strong potential for electromagnetic interference shielding, particularly in defense applications requiring radar invisibility.

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