Sürdürülebilir Kalkınma Amaçları

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• MakaleAçık Erişim2025/r/gumushane/19780
  Production of Pure PVC, Graphene and Carbon Nanotube-Doped PVC Electrospun Nanofiber Membranes: A Highly Effective Method for Removing Acid Blue 74 Dye from Wastewater

  Bozbeyoglu, Pinar; Ozkan, Vildan

  Dyeing wastewater is produced by various industries, including textiles, cosmetics, tanning, and plastics. Annually, about 1.6 million tons of dyes are manufactured, with 10-15% released into the environment as wastewater. Organic dyes are particularly harmful pollutants, even at low concentrations. The adsorption technique has proven effective for removing these pollutants from water, significantly relying on the properties and efficiency of the adsorbent. Nanofibers are emerging as promising adsorbents for dye removal due to their unique properties and high efficiency. This research focuses on polymeric nanofibers to address global dye pollution, as they effectively eliminate various dyes and contaminants. However, their mechanical properties can be a limitation under harsh conditions. To enhance their strength and hydrophilicity, incorporating nanofillers like carbon nanotubes and graphene oxide has shown significant benefits. This study examines the impact of different nanofibers on the adsorption of Acid Blue 74 (AB74) dye. Pure, carbon nanotube-doped, and graphene-doped PVC nanofibers were produced via electrospinning. Their properties were analyzed using FTIR and SEM, while key parameters such as contact time, adsorbent dosage, dye concentration, and pH were assessed to understand the adsorption behavior. Additionally, dye adsorption isotherms and kinetics were investigated.

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• MakaleAçık Erişim2025/r/gumushane/19580
  Optimizing Reflow Soldering Oven Temperature Control: A Mathematical Approach with First-Order Modelling and PI Controller Design

  Altan, Aytaç; Yanarates, Cagfer

  This paper presents a comprehensive analysis of the identification and control of a reflow soldering oven, with the primary goal of developing a Proportional-Integral (PI) controller to ensure precise temperature regulation and high-quality solder joints in circuit board manufacturing. The study begins by examining the generic thermal profile of a reflow soldering oven, offering insights into its temperature dynamics and control requirements. A mathematical model of the oven is derived using a first-order transfer function with transport delay, based on system response analysis. This model serves as the basis for designing and tuning the PI controller. The design process involves a systematic approach, including model validation and performance analysis under various operating conditions. The optimization of temperature control focuses on minimizing overshoot, compensating for steady-state errors, and ensuring robust responses to disturbances. Comprehensive simulations are conducted to evaluate the system's performance and stability, taking into account potential disturbances, noise, and time delays. The effectiveness of the developed PI controller is validated through comparisons with a simple Proportional (P) controller, and its accuracy is verified using the pole placement method. The results demonstrate significant improvements in temperature control, highlighting the controller's ability to precisely maintain desired thermal profiles.

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• MakaleAçık Erişim2024/r/gumushane/20032
  EEG Sinyallerinden Meta-Sezgisel Optimizasyon Algoritmalarına Dayalı Özellik Seçimi

  Gedikli, Eyup; Yurdusever, Taner

  Özellik seçimi makine öğrenmesi alanında, sınıflandırma işlemlerinin öncesinde bulunan önemli bir aşamadır. Ayırt edici özelliklerin iyi belirlendiği durumlarda, sınıflandırma başarı performası artar ve daha az özellik değerlendirildiği için hesaplama maliyeti azalır. Elektroensefalografi (EEG) yöntemi ile beynin spontan elektrik aktiviteleri ölçülmektedir. EEG sinyallerinin analiz edilmesiyle, duygu durumu, hastalık teşhisi, anomali tespiti yapılabilmektedir. Bu çalışmada, EEG sinyallerinden epilepsi teşhisi amacıyla, sınıflandırmada kullanılan özelliklerin seçilmesine çalışılmıştır. Kullanılan verisetinde, epileptik ve sağlıklı bireylerden oluşan 2 sınıf mevcuttur. Verisetinde, EEG sinyallerinin alt bileşenlerinden 667 özellik vardır. Sınıflandırma için bu 667 özelikten meta-segisel optimizasyon algoritmaları ile ayırt edici özellikler seçilmiştir. Sınıflandırma için k en yakın komşuluk algoritması kullanılmıştır. EEG sinyallerinin alt bileşenlerinin tamamı ile yapılan sınıflandırmada, %60,05 doğruluk başarısı elde edilmiştir. Gri Kurt Optimizasyonu, Balina Optimizasyonu ve Harris Şahinler Optimizasyonu metasezgisel algoritmaları ile özellik seçimi sonucunda, sınıflandırma başarısı %80,16 olarak elde edilmiştir. Bu sınıflandırma başarısı 5-10 özellik kullanılarak elde edilebilmektedir. Sonuç olarak meta-sezgisel optimizasyon algoritmaları ile daha az özellik seçilerek doğruluk oranı artmış ve hesaplama maliyeti azalmıştır.

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• MakaleAçık Erişim2024/r/gumushane/19994
  Dc regulation and loop gain analysis of a dc-dc switch mode power supply: a case study on a synchronous pwm controlled buck converter

  Altan, Aytaç; Yanarates, Cagfer

  This study investigates the DC regulation of a DC-DC buck converter operating with pulse width modulation (PWM), taking into account the internal resistance of the coil and the on-resistance of the switching device. The effect of these parameters on the input/output disturbances is analyzed in continuous-conduction mode under constant frequency voltage mode control. The study also explores the effect on loop gain using the IRU3037 8-pin IC synchronous PWM controlled buck converter. The transfer function of the IRU3037 IC is derived from datasheet values using state-space averaging and AC small signal methods. A Type II compensator is then designed based on the derived transfer function. In addition, the step response characteristics of the open-loop and closed-loop circuits are investigated by time domain analysis.

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• MakaleAçık Erişim2024/r/gumushane/19904
  Assessment of Hazards and Risks in a Marble Quarry

  Demir Şahin, Demet; Eker, Hasan

  Potential hazards and risks in marble quarries in Türkiye occur as a result of various factors. These include violations of occupational safety standards, equipment failures, changes in geological structure, lack of worker training and environmental impacts. However; occupational accidents occurring in industrial environments such as marble quarries can be due to various reasons. These may include factors such as falls, equipment failures, rock falls, chemical exposures and fatigue. The L matrix risk assessment method is a management tool used in many areas of industry. This method enables prioritisation of risks by evaluating the probability and impact of the risk on a matrix. The L matrix risk assessment method determines the probability and impact of each of these factors and visualises them on a matrix. The probability and impact values are ranked from low to high and the risk level is calculated by multiplying these values. This method can be an effective tool for identifying, prioritising and managing hazards and risks in marble quarries. However, for a complete and comprehensive assessment, it is important that enterprises cooperate with experts and act in accordance with local regulations. This study analyzed the hazards and risks in a marble quarry in Türkiye with the L-type risk assessment method. The results obtained show that intolerable risks such as tipping over of heavy machinery, falling rocks and breaking off large pieces in marble quarry drilling and open pit mining areas can have fatal consequences. Other significant risks in the open pit area include elements such as machinery and equipment impact, falling parts and dust. In addition, hygiene issues were considered a significant risk in open pit and general operating areas. On the other hand, breakdowns and traffic accidents are classified in the tolerable and mild risk group. This evaluation forms an important basis for taking the necessary measures to increase occupational safety. In this context, hazards and risks in a marble quarry in Türkiye were identified and risk assessment was carried out using the L-type risk assessment method.

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• MakaleAçık Erişim2024/r/gumushane/19903
  Compact analysis of the necessity of padé approximation for delayed continuous-time models in lqr, h-infinity and root locus control strategies

  Altan, Aytaç; Yanarates, Cagfer

  This paper presents a comprehensive analysis of the need for the Padé approximation for continuous-time models with delays, focusing on its critical role in addressing the control challenges posed by time delays. Time delays, often referred to as dead times, transport delays or time lags, are inherent in a wide range of industrial and engineering processes. These delays introduce phase shifts that degrade control performance by reducing control bandwidth and threatening the stability of closed-loop systems. Accurate modelling and compensation of these delays is essential to maintain system stability and ensure effective control. This paper highlights the difficulties that arise when using advanced control techniques such as root locus (RL), linear quadratic regulator (LQR) and H-infinity (H_∞) control in systems with delays. Representing delays in exponential form leads to an infinite number of state problems, complicating the design and analysis of controllers in such systems. To address these challenges, the Padé approximation is proposed as an effective method for approximating time delays with rational polynomials of appropriate order. This approach allows for more accurate simulation, system analysis and controller design, thereby mitigating the problems caused by delays. The paper also provides a detailed comparative analysis between the Padé approximation and Taylor polynomials, demonstrating the superiority of the former in achieving accurate delay modelling and control performance. The results show that the use of Padé approximation not only improves the accuracy of system models, but also improves the robustness and stability of control strategies such as RL, LQR, and H_∞. These results highlight the importance of the Padé approximation as a valuable tool in the design of delay-affected control systems, offering significant advantages for both theoretical and practical applications.

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• MakaleAçık Erişim2023/r/gumushane/20316
  On Darboux Frames of Indicatrices of Spacelike Salkowski Curve with Spacelike Binormal in E13

  Mazlum, Sümeyye Gür; Aksan, Birkan

  The aim of this study is to examine Darboux frames and some other geometric properties (geodesic curvatures, geodesic torsions, normal curvatures, Darboux derivative formulas, Darboux vectors, angles, etc.) of the spherical indicatrices on Lorentzian unit sphere S_1^2 and hyperbolic unit sphere H_0^2 of the spacelike Salkowski curve with spacelike binormal in Lorentzian 3-space E_1^3. In this context, new and interesting results have been obtained for this curve. Thus, relationships between the newly obtained curvatures and torsions and the curvature and torsion of the original curve are given. Moreover, the matrix relationship between the Darboux and Frenet frames of these indicatrices is shown. Finally, the Darboux vectors belong to the Darboux frames and the Darboux vectors belong to the Frenet frames of these curves are compared.

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