İlgi alanları

Sürdürülebilir Kalkınma Amaçları

• 10
• 7
• 2
• 2
• 1

• MakaleAçık Erişim2026/r/gumushane/13848
  Variability of Schmidt Rebound Values in Volcanic Rocks (Basalt and Lapilli Tuff): Comparative Effect of Surface Roughness, Alteration, and Testing Methods

  Karaman, Kadir; Külekçi, Gökhan; Çakır, Yaşar; Kolaylı, Hasan

  Enhancing the sustainability and safety of rock engineering requires understanding how micro-structural and alteration conditions influence the geomechanical properties of rocks in geotechnical projects. The determination of surface hardness using the Schmidt Hammer is an interdisciplinary experimental method employed in mining, geology, and civil engineering. This study quantitatively evaluates the effects of surface roughness, weathering degree, and evaluation procedures on Schmidt rebound values obtained from basalt and lapilli tuff. Field measurements on eight surfaces produced rebound values between 10 and 60, with standard deviations ranging from 2.4 to 11, reflecting substantial variability related to roughness and alteration. Laboratory results showed that cut surfaces yielded the highest hardness values (Mean ≈ 57–58) with very low variability (SD ≈ 1.1–1.6), whereas natural surfaces exhibited markedly lower rebound values (Mean ≈ 19–22) and greater scatter (SD ≈ 4–4.5). A strong correlation (R2 > 0.97) was observed between JRC roughness and rebound values in laboratory-prepared samples. The percentage difference among the USBR, ASTM, and Sumner & Nel methods remained below 5% when the standard deviation of measurements was under 2, indicating that method selection becomes critical only for heterogeneous surfaces. Mineralogical heterogeneity further increased variability in lapilli tuff, whereas basalt provided highly consistent responses. Overall, this study introduces quantitative thresholds linking roughness, weathering, and statistical variability, offering a more rigorous and reproducible framework for interpreting Schmidt hardness measurements.

  İncele
• MakaleYalnız künye2026/r/gumushane/12284
  Variable-speed retrofit of a legacy slurry pumping duty: Measured energy reduction with proxy-based operability assessment

  Külekçi, Gökhan; Aygün, Muhammet; Göller, Zafer; Yildiz, Onur

  Legacy ore beneficiation plants often operate slurry pumps at fixed speed despite variable sump inflow and slurry conditions, which can increase electricity demand and complicate level control. This study evaluates a variable-speed retrofit in which a variable frequency drive was integrated with level feedback and proportional-integral control for a legacy slurry pumping duty. Measured average operating power decreased from 25.6 kW before retrofit to 11.6 kW after implementation, documenting a substantial reduction in electrical demand under the observed operating regime. Because hydraulic-duty data were unavailable for both periods, this result is not presented as a duty-normalised specific-energy reduction. Process interpretation was supported by a bounded proxy framework based on a flowsheet-consistent solids band over 177 days. The proxy analysis linked solids variability to derived slurry density behaviour and operability implications. Overall, the study documents measured electrical-demand reduction and provides a framework for discussing retrofit performance where plant instrumentation is limited.

  • 
  • 
  • 
  İncele
• MakaleYalnız künye2025/r/gumushane/12406
  First evaluation and ecological risk of potentially toxic elements in the formations of Akçakale cave (Gümüşhane-NE-Türkiye)

  Saydam Eker, Çiğdem; Külekçi, Gökhan; Uçak, Gül

  In this study, the potential toxic element levels (PTEs) and adverse health effects of Akçakale cave formations were evaluated using geochemical parameters such as enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF), ecological risk factor (Eri), potential ecological risk index (PERI), and non-carcinogenic hazard index (HI). Water does not pose a pollution risk, as the concentrations of potentially toxic elements in all samples are within the permissible limits for drinking water. According to the calculated geochemical parameters, all the samples were polluted with As, Co, Ni, Cu, V, and Pb. Ni, As, Cu, and Pb show very high ecological risk (PER > 320) in all samples, except Cu and Pb in T2T. The PERI values of the PTEs were more than 600 in all samples, indicating a very high potential ecological risk. The HI > 1 values for Co and As in all samples for both adults and children suggested potential non-carcinogenic health risks from exposure to these elements in the cave environment. The PTEs in the Akçakale cave formation were most likely linked to lithogenic, geogenic (Pb–Zn-Cu mineralization), and anthropogenic (agricultural activities) processes, per the findings of the data analysis using multivariate statistics (PCA and PCC). These data obtained are the first findings regarding the potential toxic element content of Akçakale cave.

  • 
  İncele
• MakaleAçık Erişim2025/r/gumushane/11780
  Enhancing mineral processing with deep learning: Automated quartz identification using thin section images

  Külekçi, Gökhan; Hacıefendioğlu, Kemal; Başağa, Hasan Basri

  The precise identification of quartz minerals is crucial in mineralogy and geology due to their widespread occurrence and industrial significance. Traditional methods of quartz identification in thin sections are labor-intensive and require significant expertise, often complicated by the coexistence of other minerals. This study presents a novel approach leveraging deep learning techniques combined with hyperspectral imaging to automate the identification process of quartz minerals. The utilizied four advanced deep learning models—PSPNet, U-Net, FPN, and LinkNet—has significant advancements in efficiency and accuracy. Among these models, PSPNet exhibited superior performance, achieving the highest intersection over union (IoU) scores and demonstrating exceptional reliability in segmenting quartz minerals, even in complex scenarios. The study involved a comprehensive dataset of 120 thin sections, encompassing 2470 hyperspectral images prepared from 20 rock samples. Expert-reviewed masks were used for model training, ensuring robust segmentation results. This automated approach not only expedites the recognition process but also enhances reliability, providing a valuable tool for geologists and advancing the field of mineralogical analysis.

  İncele
• MakaleAçık Erişim2024/r/gumushane/19987
  Çevresel Tehlikelerin Belirlenmesi ve Sağlık Etkilerinin İncelenmesi: Gümüşhane Katı Atık Tesisi Örneği

  Güvendi, Aslıhan; Külekçi, Gökhan

  Bu çalışmada, Gümüşhane ilindeki katı atık tesisinin iş sağlığı ve güvenliği Elmeri yöntemi kullanılarak incelenmiştir. Katı atık yönetim süreci, atık toplama, taşıma, ayrıştırma, geri dönüşüm ve bertaraf gibi adımları içermektedir. Bu süreçlerde potansiyel olarak ortaya çıkabilecek; atık toplama sürecinde, keskin kenarlı ve delici maddelerin bulunmasıyla oluşabilecek kesilmeler ve delinmeler, atıkların taşınması sırasında ağır yüklerin kaldırılmasıyla ilgili bel ve sırt yaralanmaları, ayrıştırma işlemi sırasında kimyasal maddelerin sızması veya bu maddelerin solunmasıyla ilgili zehirlenme veya solunum yolu rahatsızlıkları, geri dönüşüm sürecinde kullanılan makinelerin veya ekipmanların yanlış kullanımıyla ilgili kırılma, ezilme veya yakma gibi kazalar, atıkların bertaraf edilmesi sırasında oluşabilecek patlama veya yangın riskleri gibi tehlikeler mevcuttur. Bu tehlikeler, Elmeri yöntemi kullanılarak tanımlanmış, çalışanların ve çevrenin bu tehlikelere maruz kalma düzeyi değerlendirilmiş ve ortaya çıkan riskler belirlenmiştir. Elde edilen sonuçlar, tesis yöneticileri ve ilgili paydaşlar için önemli bir kaynak olabilir ve katı atık yönetiminde daha etkili önlemlerin alınmasına yardımcı olabilir. Bu çalışma kapsamında Elmeri yönteminde belirtilen 7 ana başlık altında toplanan metotlara göre çalışma alanlarında toplam 494 adet gözlem yapılmıştır. Yapılan gözlemlerden 239 tanesi doğru güvenlik davranışı ve durumları belirtirken 255 tanesi yanlış güvenlik davranış ve durumlarını belirtmektedir. Gözlem sonuçlarına göre çalışma alanlarındaki en yüksek mevcut güvenlik endeksi % 57,2 ile atık toplama gündüz vardiyası, en düşük indeks ise % 29,3 ile atık ayrıştırma kısmında hesaplanmıştır.

  • 
  • 
  • 
  İncele
• MakaleAçık Erişim2024/r/gumushane/11956
  Performance of different fibre types in alkaline-activated concrete produced with industrial wastes: volcanic rock powder and blast furnace slag

  Aksüt, Yavuz Selim; Külekçi, Gökhan; Çullu, Mustafa; Yetgin, Şükrü

  The objective of the study is to determine the effects of different fibre types and ratios on the mechanical and physical properties of alkali-activated concrete (AAC) and to optimise important properties such as workability, unit weight, water absorption, compressive strength, modulus of elasticity and abrasion resistance of these concretes. Concrete samples were produced using steel and polyester fibres at ratios of 0.25%, 0.50%, 0.75% and 1%. The fibre ratios were varied, and various tests were conducted to determine the mechanical and physical properties of the concrete samples. The experiments clearly revealed the effects of fibre types and ratios on the performance of concrete. These results clearly demonstrate the effects of different fibre types and ratios on the mechanical and physical properties of AACs. Particularly noteworthy is the water-retaining property of polyester fibres, their effect on workability and their enhancing effect on abrasion resistance. The effects of steel fibres on compressive strength and modulus of elasticity are more pronounced, but they may present disadvantages in terms of workability and abrasion resistance. It is observed that mixed fibre usage provides a good balance in some properties. This study provides a roadmap for evaluating sustainable material options in the concrete industry and guiding future research.

  • 
  İncele
• MakaleYalnız künye2023/r/gumushane/12741
  Mechanical Properties of Shotcrete Produced with Recycled Aggregates from Construction Wastes

  Külekçi, G.; Çullu, M.; Yilmaz, A.O.

  Abstract: This study examines the usability of concrete wastes generated from buildings demolished for various reasons in shotcrete. The strength properties of shotcrete produced from recycled aggregates (RA), cylinder specimen and plate specimen were tested. it was observed that as the ratio of RA used instead of natural aggregate increases, the strength of the cylinder specimen decreases, ultrasonic pulse velocity increases. The toughness value has increased in the concrete samples prepared by replacing the natural aggregate with 50% or more RA. It was observed that the fiber amount and load carrying capacity were proportional in fiber reinforced plates prepared using RA. As a result, it has been observed that the interaction of RA with fiber is positive and it can be used in shotcrete. It has been revealed that RA can contribute to the reduction of environmental pollution caused by construction and wreckage wastes and can be presented as an alternative to natural aggregate.

  • 
  İncele
• MakaleYalnız künye2022/r/gumushane/17188
  Investigation of usability of building rubble as road underfill

  Külekçi, Gökhan; Osman Yilmaz, Ali

  For resources to be used efficiently, the structures built on the earth must be long-lasting. The longevity of the roads built with a length of millions of kilometers per year is determined by the nature of the filling material, traffic, equivalent axle load, climatic effects, material fatigue, and layer thicknesses used. The fact that filling material complies with the standards and is easily available will ensure that the road construction works are both economical and long-lasting. Many building rubbles are formed from the buildings that have completed their lives in the urban transformation process. Storage and disposal of this building's rubble are very difficult. To eliminate these difficulties, the usage areas of the rubble should be increased. In this study, some mechanical experiments were carried out on the building rubble obtained from the Black Sea region, and these were interpreted. Grain density, freeze-thaw tests, Micro-Deval, and Determination of Fragmentation Resistance, tests were carried out according to TSE and ASTM standards of aggregates obtained from building rubble. The results obtained from the experiments were compared with the technical specifications of the General Directorate of Highways. It has been revealed that the analyzed aggregate can be used as road fill in highways.

  • 
  • 
  • 
  İncele
• MakaleYalnız künye2022/r/gumushane/14742
  Assessment of excavability classification in a Limestone Quarry: A case study from Bayburt, Turkey

  Külekçi, Gökhan; Vural, Alaaddin; Aliyazicioğlu, Şener

  Excavability is a measure of material which can be excavated with classical excavation equipment. Studies to decide the rock excavability characteristics contribute to the suitability of engineering projects. In this study, a limestone quarry (in Bayburt, Turkey) was analysed with excavability classification systems and appropriate systems were determined. To accomplish this aim, point load index and Schmidt hardness tests were practiced and changed to uniaxial compressive strength tests. After that, findings were categorized with classification systems in excavation and matched against practices from field. In this study, rock mass was addressed as “pre-explosion”, “hard ripping” and “hammer and blasting” in accordance with distinctive classification systems. All determined as rock mass should be blasted for loosening then dug with hydraulic breakers. This practice is totally compatible with in-site excavations fulfilled. According to study results, the most suitable parameters to decide surface excavational classification are load strength index, geological strength index and the degree of rock mass weathering

  İncele
• MakaleAçık Erişim2022/r/gumushane/14562
  Investigation of gamma ray absorption levels of composites produced from copper mine tailings, fly ash, and brick dust

  Külekçi, Gökhan

  To date, heavyweight concretes have been produced from various heavy aggregates as radiation insulation materials, and their gamma ray absorption levels have been investigated. Many of the studies have used heavy aggregates instead of cement or coarse aggregates from composite material components. The present study prepared lightweight concretes using copper mine tailings, clay brick dust, and fly ash instead of fine aggregates. Some mechanical tests (density, compressive strength, and ultrasonic pulse velocity) were performed on composite blocks with dimensions of 5*5*5 cm, and radiation interaction parameters [linear absorption coefficient (cm−1), mass attenuation coefficient (cm2/gr), HVL (half-value layer) (cm), MFP (cm), and permeability (%)] were measured. Radiation interaction parameters were obtained using a HPGe gamma detector. Radiation measurements were performed at five different photon energies: 583 keV (133Ba), 609 keV (133Ba), 662 keV (137Cs), 911 keV (133Ba), 1173 keV (60Co), and 1332 keV (60Co). Additionally, the compressive strength and UPV values of composite materials were associated with their gamma ray permeability. Tests revealed that samples with the addition of copper mine tailings yielded the best energy absorption at all energy levels and that absorption decreased as the energy level increased. For example, with the increasing of the energy level, mass attenuation coefficients decreased. The highest mass attenuation coefficients were obtained as 0.128 cm2/g at an energy level of 583 keV in composites produced from copper mine tailings. On the other hand, it was measured at the same energy level as 0.069 cm2/g (a 46% decrease) in the composites produced with fly ash. In addition, it was observed that fly ash used as a fine aggregate did not have a significant effect on mass attenuation coefficient and could be used as a gamma shield if the material thickness was increased to an average of 14 cm. This study revealed that tailings materials could be used as radiation shields. This study also demonstrated that not using heavy aggregates and producing lightweight concrete in radiation shield production significantly reduced shield production cost.

  • 
  İncele