Sürdürülebilir Kalkınma Amaçları

• 2
• 1
• 1

• MakaleAçık Erişim2026/r/gumushane/19374
  A New Caputo-Fabrizio Hybrid Method for the Numerical Solution of Caputo-Fabrizio Fractional Epidemic Model

  Anaç, Halil; Alkan, Asli

  This paper presents a novel Caputo–Fabrizio hybrid numerical method for examining the dynamics of fractional epidemic models defined by memory effects and non-singular kernels. The proposed method combines the Caputo–Fabrizio fractional derivative with a hybrid transform framework, facilitating the derivation of accurate and convergent approximate solutions for nonlinear epidemic systems. The model's parameters are analyzed in relation to infection transmission and recovery dynamics, whereas the fractional order α regulates the magnitude of memory and genetic influences. Numerical simulations indicate that the novel hybrid method exhibits remarkable concordance with established results for integer-order scenarios, while showcasing enhanced precision, computing efficiency, and robustness in fractional contexts. The suggested method offers a versatile and effective analytical instrument for investigating real-world epidemic occurrences exhibiting long-term memory traits.

  İncele
• MakaleAçık Erişim2025/r/gumushane/19703
  Seasonal Wilcoxon and Scatter Diagram Combination Trend Test

  Şan, Murat

  Climate change, one of the biggest problems of the last century, is of great concern. It is essential and common to examine the impacts of climate change as a holistic trend for different climatic and hydrological parameters with periodicity. However, considering the periodicity character of monthly, weekly, etc., is particularly important for analyzing and understanding seasonal trends. This is because seasonal trends help manage and regulate irrigation and agricultural activities and water resource systems. This study proposes the seasonal Wilcoxon and scatter diagram combination trend test (SWTT) method as an alternative to the seasonal Mann Kendall (SMK) method. This method is based on the combination Wilcoxon test and scatter diagram (CWTSD) trend test which assesses holistic trends. The data utilized for this study came from three sources: flow records from the Danube River, Romania, temperature records from Oxford, UK, and precipitation records from Kobe, Japan, to compare SWTT and SMK methods. The SWTT method shows very similar trends to the SMK, but the SWTT method takes a step forward because it is based on a graphical method providing a visual overview of seasonal trends. The SWTT can also be used as a regional trend test in the same way that the SMK method is used as a regional trend test by using station data instead of seasons The r-codes of the proposed method and the sample dataset are available at the related link.

  • 
  İncele
• MakaleAçık Erişim2024/r/gumushane/20117
  Bishop Frames of Salkowski Curves in E3

  Mazlum, Sümeyye Gür

  In this study, alternative, type-1 Bishop, type-2 Bishop and N-Bishop frames of Salkowski curves in E3 are calculated. Moreover, curvatures, Darboux and pol vectors of these frames are found. Also, relationships between the Bishop frames, Darboux vectors and pole vectors are given.

  İncele
• MakaleAçık Erişim2024/r/gumushane/19985
  Thermal Power Plant Performance Analysis by Estimating Boiler Efficiency via Indirect Method: A Case Study

  Celen, Pinar; Erdem, Hasan Hüseyin

  In this paper, a coal (lignite) fired thermal power plant having capacity of 160 MW is taken into consideration and the impact of condenser pressure, moisture content of lignite, excess air coefficient, the efficiency of turbine pressure and heater numbers on power plant thermal efficiency is investigated. It is aimed to determine the performance losses of each equipment by means of thermodynamics and economic analysis. In this scope, it is expected that the power plant operator will be able to evaluate the reduction potential of equipment performance losses and ensure more effective use of the power plants by correctly planning the maintenance and rehabilitation needs and time. In the calculations, the boiler efficiency was determined with EN 12952-15 standard (indirect method) since this method has higher accuracy in coal-fired boilers. It is seen that the condenser pressure and excess air coefficient increments have no significant impact on power plant efficiency compared to moisture content of lignite, excess air coefficient, efficiency of turbine pressure and heater numbers. The significant effect is observed for fuel moisture content which rises from 22% to 47% and the power plant efficiency falls from 40% to 28%. The variation of the power plant thermal efficiency in case of failure of heaters is investigated and the power plant efficiency has decreased from 40.17% to 36.09% when the pre-heaters are no longer in to be in use because of any reason. In addition, revenue losses are estimated for each main equipment efficiency reduction for better use of power plant capacities and electricity lowering production costs.

  • 
  • 
  • 
  İncele
• MakaleAçık Erişim2022/r/gumushane/17037
  Stachys macrantha (K.Koch) Stearn’ın Biyolojik Aktivitesinin Belirlenmesi

  Ozcan, Kadriye; Acet, Tuba

  Stachys, Lamiaceae familyasının en geniş yayılış gösteren cinslerinden birisidir. Bu cinse ait türler biyolojik aktiviteleri ve etnomedikal kullanımları ile bilinmektedir. Bu çalışmada, Stachys macrantha’nın toprak üstü kısımlarının farklı çözücülerle (etanol, metanol ve etil asetat) elde edilen ekstraktlarının toplam fenolik ve flavonoid içeriği ile antioksidan (ABTS, DPPH) ve enzim inhibisyon (α-amilaz, α-glukozidaz, bütirilkolinesteraz ve asetilkolinesteraz) aktiviteleri spektrofotometrik yöntemlerle araştırılmıştır. Ayrıca, fenolik bileşen analizi HPLC ile analiz edilmiştir. Bulgulara göre, metanol ekstraktının diğer ekstraktlara kıyasla biyolojik aktivitelerinin dikkat çekici olduğu bulunmuştur. Ekstraktın, toplam fenolik (45.57 mg GAE/g ekstrakt) ve flavonoid (54.48 mg QE/g ekstrakt) içeriği, antioksidan özellikleri [ABTS (49.99 mg TE/g ekstrakt), DPPH (23.62 mg TE/g ekstrakt)] ile enzim inhibisyon aktiviteleri [α-amilaz (159.35 mmol ACE/g ekstrakt), α-glukozidaz (8.78 mmol ACE/g ekstrakt), bütirilkolinesteraz (5.85 mmol ACE/g ekstrakt) ve asetilkolinesteraz (1.25mmol ACE/g ekstrakt)] belirlenmiştir. Metanol ekstraktının majör fenolik bileşenlerinin kaemferol (539.65 µg/g ekstrakt) ve kuersetin (271.65 µg/g ekstrakt) olduğu tespit edilmiştir. Elde edilen sonuçlara göre, bitkinin tespit edilen aktiviteleri sayesinde ilaç, gıda ve kozmetik endüstrilerinde kullanılma potansiyeli olduğu söylenebilir. Bununla birlikte, söz konusu verilerin daha ileri çalışmalarla desteklenmesi ve aktif bileşenlerin saflaştırılarak etkilerinin in vivo ortamlarda belirlenmesi gerekmektedir.

  İncele