Sürdürülebilir Kalkınma Amaçları

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Araştırmacılar(4)

• Güngör, Osman
• Teber, Ahmet
• Tozlu, Alperen
• Yarımkaya, Derya

• 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

  İncele
• MakaleAçık Erişim2025Scopus SJRQ1/r/bayburt/11242
  Design, Simulation, and Fabrication of High-Performance Metamaterial Absorber for EMI Mitigation and THz NDT/Imaging Applications: A Shape-Preserved GHz-to-THz Transition Approach

  Teber, Ahmet

  A metamaterial absorber (MMA) designed for the 5G FR2/mmWave bands (24.25–24.45 and 24.75–25.25 GHz) is simulated with CST Studio Suite and fabricated using laser and wet etching techniques. Absorption measurements are performed using horn antennas in conjunction with a vector network analyzer (VNA). The absorber achieves >95.8% absorption under normal incidence for Mode-1, while it exceeds 90% for Mode-2 in the 24.75–25.20 GHz. The simulation results are validated through an electrical equivalent circuit model and experimental data. This absorber presents a promising solution for electromagnetic interference (EMI) reduction and shielding applications. The same structure, scaled from mm to µm without shape alteration, achieved over 90% absorption in the terahertz (THz) region (24–26 THz), particularly in the 24–25.12 THz range. The THz region, known as the “THz gap”, presents challenges due to limited THz sources and detectors. However, technologies such as THz non-destructive testing (NDT) offer potential in biomedical, communication, and defense applications. From this perspective, the high performance and scalability to µm dimensions without changing the shape of the absorber make it suitable for high-frequency EM shielding applications. This dual behavior in the GHz and THz regions offers a versatile advantage due to its varied functionality.

  AtıfScopus4·WoS4·OpenAlex3

  İncele
• MakaleAçık Erişim2024/r/bayburt/16379
  Refractive Index Sensor Based on Terahertz Metamaterial Absorber with High Sensitivity and Quality Factor for Sensing Applications

  Teber, Ahmet

  This research describes and assesses a terahertz metamaterial absorber (TMA) with a simple and easy-to-produce structure consisting of gold-silicon (optical)-gold design as a refractive index sensing. Due to the high field limitation in the detection regime, electromagnetic (EM) wave’s absorption reaches 99.40% at a frequency of 3.719 THz, including a significant quality factor (Q-Factor) of 65.77 and a figure of merit, FoM, of 21.49. The TMA has an remarkable sensitivity of 1.215 THz/RIU and can be used as a refractive index sensor (RIS). The proposed metamaterial absorber-based sensor is susceptible to refractive index changes (1.00 to 1.05) in the surrounding medium. For the physical absorption mechanism, the fundamental absorption peak is mainly due to the simultaneous occurrence of electric and magnetic dipole resonances. The proposed absorber has the feature of being an excellent RIS due to its sensing and detection applications.

  AtıfOpenAlex3

  İncele
• MakaleAçık Erişim2024Scopus SJRQ1/r/bayburt/11647
  FR2/mmWave, N258 and N261 Bands, 5G Frequency-Compatible Ultra-Thin Metamaterial Absorber with Polarization Insensitivity for EMI shielding Applications

  Teber, Ahmet

  Since adopting 5G technology, a notable rise in the prevalence of electromagnetic (EM) waves in the environment has become a significant concern. To reduce EM interference, broadband metamaterial absorbers offer an alternative solution for protecting devices in defense, communication, and healthcare applications, unlike their narrowband counterparts. This article presents a numerical investigation of an ultra-thin, polarization-insensitive metamaterial absorber (MMA) that uses metasurfaces and provides electromagnetic interference (EMI) reduction, covering the FR2/mmWave licensed N258 and N261 bands with an oblique incidence angle of up to 15 degrees. Comprehensive simulations are performed within the CST Studio Suite S2 2023 to examine the absorber's performance. Under normal incidence, the proposed MMA exhibits a wideband absorbency response exceeding 90% within the frequency range of 24.30–28.12 GHz. Moreover, the physical absorption mechanism is explained with electric and magnetic field distributions, including surface current distributions. Confirmation of the lack of mutual interaction among neighboring unit cells is established through testing with 1 × 2 and 2 × 2 arrays. An equivalent circuit model is also developed to confirm the EM simulation findings. The notable features of the proposed MMA make it an exceptional candidate for EM shielding applications, providing EMI reduction and covering the N258 and N261 bands.

  AtıfScopus7·WoS3·OpenAlex5

  İncele
• MakaleAçık Erişim2023/r/bayburt/16511
  Eliptik Şekilli Metayüzeye Dayalı Geniş Bant Polarizasyon Dönüşümü

  Teber, Ahmet; Ertugrul, Mehmet; Coşkun, Aykut

  Burada, geniş bant yansıtıcı doğrusal polarizasyon (LP) ve dairesel polarizasyon (CP) dönüşümlerini gerçekleştirmek için tek katmanlı, ultra ince, çok işlevli ve yüksek verimli bir meta-yüzey sunulmaktadır. Önerilen meta-yüzey, %97'den fazla verimlilikle %55.2'lik (7.89-13.91 GHz) nispi absorpsiyon bant genişliği (RAB) üzerinde doğrusal polarize dalga için mükemmel bir çapraz polarizasyon dönüştürücü görevi görür. Doğrusal polarize dalgaları 7.2–7.36 GHz frekans aralığında başarıyla dairesel polarize dalgalara dönüştürür. Ek olarak, TE ve TM modları için polarizasyon dönüşüm oranı (PCR) verimlilik özellikleri, 45⁰'ye kadar geniş bir geliş açısı ile tüm X bandında korunur. Sunulan polarizasyon dönüştürücü, 0.07λ0 kalınlık ile ultra ince bir özelliğe sahiptir. Kompakt boyutu, açısal kararlılığı, yüksek verimliliği, basit yapısı ve çok işlevliliği nedeniyle bu polarizasyon dönüştürücü, birçok uygulamada polarizasyon manipülasyonu ve iletişim cihazları için önemli bir adaydır.

  AtıfOpenAlex1

  İncele
• MakaleAçık Erişim2022Scopus SJRQ3/r/bayburt/11630
  IoT-TDMA: A performance evaluation of TDMA scheme for wireless sensor networks with Internet of Things

  Kosunalp, Selahattin; Kaya, Yunus

  This article focuses on the design and implementation of an improved version of TDMA scheme for wireless sensor networks (WSNs) exploiting the Internet of Things (IoT) phenomena. The main motivation behind this work is to create an environment for WSNs to benefit from IoT opportunities. An extensive review of the state-of-the-art medium access control (MAC) approaches proposed for IoT is carried out underlying their basic principles and features. An adaptation of TDMA strategy, called IoT-TDMA, is proposed to enhance the channel performances particularly throughput and latency. To test the performance of IoT-TDMA practically, a low-cost node hardware with the capability of Internet connection is essentially designed. IoT-TDMA has been implemented on real-world highly scalable single-hop and multi-hop topologies. Performance results indicate significant improvements in terms of channel throughput and end-to-end delay in comparison to a recently proposed efficient MAC scheme.

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  AtıfScopus17·OpenAlex18

  İncele
• MakaleAçık Erişim2020/r/bayburt/14850
  Ranking alternative energy resources technology programsin turkey based on the methods of multi-criteria decisionmaking analysis

  Teber, Ahmet; Karakaş, Ahmet

  The diversity less among the Alternative Energy Resources Technology Programs (AERTPs) in Turkey makes giving the “proper” decision crucial by high school senior students. The literature review exhibits that there exists a need over the expectation for a ranking system of the two-year programs in vocational schools in Turkey so as identifying two-year programs compared to others. In this strategic decision context, it is especially important for the students to make a suitable decision associated with their higher education. Therefore, this study focuses on developing a specific ranking system of twoyear energy programs in Turkey. In order to classify the programs, the most important decision criteria should be required. In this aspect, a survey is applied to a hundred high school senior students to recognize which multi-criteria for selection of an energy program they pick. Thus, the survey makes this study is more applicable to build a foundation for a field-based ranking system in Turkey. In this regard, a framework for ranking of AERTPs during the academic year of 2019 in Turkey is accomplished using three methods of Multi-Criteria Decision Making Analysis including Analytic Hierarchy Process (AHP), Simple Multi-Attribute Rating Technique (SMART), and Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).

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  AtıfOpenAlex1

  İncele
• MakaleAçık Erişim2020/r/bayburt/12077
  Investigation of Beam Width Shaping of a Ku-band Horn Antenna using a Diffractive Optic Element and an Electromagnetic Wave Absorber

  Teber, Ahmet

  The feasibility of beam-shaping of a Ku-Band horn as a transmitting (Tx) antenna by mounting two different versions of lenses which are kind of Fresnel Zone Plates (FZP) is studied. The designed and fabricated geometrical structures offer a simpler approach building Fresnel Zone Plates by using an electromagnetic wave absorber and diffractive optic material. The diffractive optic material, paraffin, forms a set of alternating open and opaque annular zones on a flat surface, based on the design principles of Fresnel Zone Plates. An electromagnetic wave absorber covers the top surface of the formed paraffin, but not including the grooves. Thereafter, the Fresnel Zone plates are suitably attached in front of the transmitter horn antenna, located in the far-field region of a receiving antenna. The half-power beam-widths for the horn antenna (unloaded) and with two types of lenses are investigated. The results indicate that Fresnel zone plate structures can play a role suppressing side lobes in H-plane so that the effective radiation is to be significantly concentrated.

  AtıfScopus1·OpenAlex2

  İncele
• MakaleAçık Erişim2019/r/bayburt/15070
  Tepsili Bir Kurutucuda Kırmızı ve Yeşil Elma Parçacıklarının Kurutma Performanslarının Karşılaştırılması

  Tozlu, Alperen

  Bu çalışmada, tepsili kurutucuda kurutulması için yeşil ve kırmızı elmalar kurutma malzemeleri olarak seçilmiştir. Kurutulacak katı gıdalar, deney sonuçlarını olumsuz yönde etkileyebilecek tüm kirletici maddelerden arındırılmak için damıtılmış su ile yıkanmış ve aynı boyutlarda kesilmiştir. Her bir elma parçasının uzunluğu, genişliği ve kalınlığı sırasıyla 65 mm, 37 mm ve 12 mm olarak ayarlanmıştır. Elma parçacıkları hassas terazilerle tartılarak 50 g, 100 g ve 200 g olarak gruplandırılmıştır. Daha sonra her deney seti için parçacıklar tepsili kurutucuya yerleştirilmiş, daha sonra, kurutma işlemi, kırmızı ve yeşil elma parçacıklarının (mp) farklı ağırlıklarında, kurutma hava hızında (U) ve kurutma sıcaklıklarında (Td) gerçekleştirilmiştir. Burada nem içeriği (MC), kurutma malzemelerinin kurutma performansını ifade etmek için önemli bir parametre olarak kabul edilmiştir. Ayrıca, enerji verimliliği ve normalleştirilmiş nem içeriği, kurutma sistemleri için önerilen ampirik denklem ile karşılaştırılmıştır. Deneysel çalışma 50 g ≤ mp ≤ 200 g, % 18 ≤ MC ≤ % 614.29, 0.03 ≤ MR ≤ 1, 59 o C ≤ Td ≤ 99 o C ve 0.992 m/s ≤ U ≤ 1.488 m/s aralığında gerçekleştirilmiştir. Bu çalışmanın sonucu, kırmızı elma parçacıklarının, yeşil elma parçacıklarına kıyasla fiziksel özellikleri nedeniyle aynı koşullarda daha iyi kurutma performansına sahip olmasıdır.

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