Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

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  • MakaleYalnız künye2025Scopus SJRQ1
    Effect of mechanical milling parameters on the properties of electrolytic pure copper powders and hot pressed billets fabricated from recycled copper wastes

    Akçay, Serhatcan Berk; Çuvalcı, Oğuzhan; Varol, Temel; Çuvalcı, Hamdullah; Kocaman, Mücahit; Alver, Ümit; Beder, Murat; Güler, Onur; Aksa, Hüseyin Can; Gasha, Shimelis Bihon

    This study was conducted to comprehensively investigate the effect of mechanical milling parameters on the properties of electrolytic pure copper powders and hot pressed billets fabricated from recycled copper wastes. Three different milling speeds, five different milling times and three different ball to powder weight ratios were used to fully reveal the effect of the mechanical milling process on the properties of recovered Cu powders. The results show that as the milling time and milling speed increased, the initial dendritic morphology of the copper was transformed into a flake-like structure. At 400 rpm and a 5:1 BPR parameters, the average particle sizes of C3, C4, and C5 after 2, 4, and 8h were ∼52 μm, 83 μm, and 71 μm, respectively. This suggests that particle size initially increases due to shape change and cold-welding, but at longer durations, fracture becomes dominant. The I5 with d(0.5) = 69.32 μm exhibited a high flow rate of 5.88 g/s with an apparent density of 2.9 g/cm3.While the hardness value of the Cu samples (A1-bulk sample) produced by exposure to the lowest deformation during the mechanical milling is 95.02 HB, the hardness value of the Cu specimens (F5-bulk sample) showing the highest apparent density, best flow rate and highest density values is 109.31 HB. The electrical conductivity values were determined to be approximately 52.2 MS/m, 57.4 MS/m and 44.3 MS/m for A1-bulk, F5-bulk and H5-bulk, respectively. This study offers valuable insights into the relationship between milling parameters, powder characteristics, and final material properties.

    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus6WoS4OpenAlex5
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  • MakaleYalnız künye2022Scopus SJRQ2
    Hidden Diversity in a Narrow Valley: Description of New Endemic Palearctic Rock Lizard Darevskia (Squamata: Lacertidae) Species from Northeastern Turkey

    Kurnaz, Muammer; Şahin, Mehmet Kürşat; Eroğlu, Ali İhsan

    Darevskia is a particularly species-rich radiation of Palearctic rock lizards from the Caucasus region. Thanks to intense systematic and taxonomic research, the knowledge of species-level diversity within this genus has increased over the last quarter century. Here, we described a new species, Darevskia salihae sp. nov. from northeastern Turkey. The new taxon is differentiated from other nearby taxon by the low number of dorsal scales in the middle of the body, the shorter body length, and the absence of blue dots both on the lateral region above the forelimbs and on the margin of the ventral plates. In addition to their morphological differences, the new taxon is phylogenetically different from close groups. It is located in a separate subclade from the rudis-valentini-portschinskii subclade. This distinction is supported by both a high bootstrap value (100) and a high posterior probability value (1.00). These two subclades are separated from each other by a genetic distance of almost 4%. This separation is supported not only genetically and morphologically, but also geographically. Since the habitat of the new taxon is limited to a high mountain and a narrow valley, it does not provide an opportunity for a different Darevskia species to shelter because it creates geographical isolation. However, Darevskia parvula that live closest to the habitat of the new taxon live only at the habitat boundaries and do not enter areas where the new taxon is found. Therefore, it might be possible that while it was separated from the rudis-valentini-portschinskii group during the evolutionary transformation, it remained as a refuge and relict in a narrow area as a result of the collapse of the valleys and the partial uplift of the Kaçkar Mountains.

    AtıfScopus6WoS5OpenAlex4
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  • MakaleYayıncıda açık erişim2021
    THE INHERITANCE OF BAGHDAD GOVERNOR AHMED PASHA (1692-1694)

    Türkal, Merve Karacay

    The subject of the study consists of the life of Ahmed Pasha, who served as the governor in Baghdad between 1692-1694, and the translation and evaluation of his inheritance book. Inheritance notebooks, which are among the historical documents of the Ottoman Empire and have an important position, enable to enlighten the socio-economic structure of the period. At the same time, inheritance notebooks belonging to these people are of great importance in terms of biography studies, as they provide information about the wealth of the individuals they belong to. The aim of the study is to contribute to the scientific studies on the economic and social life of the Ottoman Empire in the 17th century. Presidency of State Archives BOA in the Ottoman Archives D.BSM. MHF. d., 12374, BOA, D.BSM. MHF. d., 12375 and BOA, D.BSM. MHF. d., 12377 registered with the numbers three separate notebooks belonging to Ahmed Pasha were translated and evaluated. This article consists of three parts: Introduction, Life of Ahmed Pasha and Inheritance of Ahmed Pasha. Based on his belongings recorded in the book, it was tried to determine the value of the wealth of an Ottoman pasha who fulfilled his duty as a governor in Baghdad in the last quarter of the 17th century. Depending on the findings determined, inferences were made about the status, tastes, preferences, in short, his social life of Pasha. Thus, besides the daily life belongings of a governor serving in the Ottoman state, a panorama of the books he read, the variety of his wealth, his clothing, household items and furnishings and war equipment is presented.

    AtıfTR Dizin6
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