Browsing by Author "Yildirim, Hasan"

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Crepis Gemicii Sp Nov (Asteraceae) From East Anatolia, Turkey
(Wiley-blackwell Publishing, inc, 2011) Yildirim, Hasan; Bingol, Omer; Armagan, Metin
Crepis gemicii Hasan Yildirim, Omer Bingol & Metin Armaan (Asteraceae) is described as a new species. Diagnostic morphological characteris, full descriptions and detailed illustrations are given on the basis of the type material. Crepis gemicii is restricted to the province of Van in east Anatolia, Turkey. It is releated to and compared with C. bupleurifolia (Boiss.) Freyn & Sint., C. paludosa (L.) Moench and C. pannonica (Jacq.) C. Koch. Its' seed and pollen ultrastructure is described based on studies with SEM.
An Experimental Investigation on Fracture Parameters of Recycled Aggregate Concrete With Optimized Ball Milling Method
(Elsevier Sci Ltd, 2020) Dilbas, Hasan; Cakir, Ozgur; Yildirim, Hasan
In this paper, Ball Milling Method (BMM) is employed on recycled aggregate (RA) with an optimization process which is conducted to enhance RA efficiently eliminating attached old mortar (AOM) content in RA. Various combinations of drum rotation (R) (100-200-300-400-500) and the steel balls (S) (0-2-5-7-10-12) applied to the recycled aggregate during the BMM process and treated recycled aggregates (RAi) are obtained. The mechanical properties (compressive, splitting tensile and flexural strength values and elasticity modulus) and the non-linear fracture parameters (effective crack length, crack mouth opening displacement, crack tip opening displacement, initial cracking toughness, unstable fracture toughness and fracture energy) of concretes including untreated and treated recycled aggregate (RAi) are determined. The test results proved that the water absorption values of recycled aggregates in the size of 4-11.2 mm and 11.2-22.4 mm reduced from 8.80% to 1.40% and 8.95% to 0.84%, respectively, after treatment process. It is also found that the compressive strength of concretes are marginally affected with the use of treated recycled aggregate (RAi) up to 60% which is twofold of the optimum recycled aggregate proportion given in the literature. Moreover, 60% RAi content in concrete can be recommended in terms of fracture characteristics (a(c), CMODc, CTODc, K-ic(ini), K-ic(un) and G(F)). (C) 2020 Elsevier Ltd. All rights reserved.
A New Bellflower, Campanula Dersimensis (Campanulaceae), From E Anatolia, Turkey
(Botanischer Garten & Botanische Museum Berlin-dahlem, 2022) Firat, Mehmet; Ozudogru, Baris; Yildirim, Hasan
Campanula dersimensis Firat & Yildirim, a new species endemic to the E Anatolian region of Turkey, is described and illustrated. It is currently known from two localities in Tunceli province (Dersim). Campanula dersimensis shows similarities to C. quercetorum Hub.-Mor. & C. Simon and C. yildirimlii Kit Tan & Sorger. A close relationship of the three taxa is also supported by phylogenetic analyses based on the nuclear-encoded ribosomal internal transcribed spacer (ITS) region. Diagnostic morphological characters are discussed and compared with those of closely related taxa. Campanula dersimensis is easily distinguished from related species, especially by its retrorsely hairy stem and leaf surface, to 1 mm long calyx appendages and glabrous and light greenish yellow to yellowish white corollas.
Prospero Cudidaghense Sp Nov (Asparagaceae): a New Species From Southeastern Anatolia, Turkey
(Tubitak Scientific & Technological Research Council Turkey, 2016) Firat, Mehmet; Yildirim, Hasan
Prospero cudidaghense Firat & Yildirim (Asparagaceae) is described as a species new to science based on morphological studies. It is endemic to the eastern Anatolian region of Turkey. P. cudidaghense is known from a single locality on Cudi Mountain, located in Sirnak Province. It is an isolated taxon of the genus Prospero. It is related to P. autumnale and P. seisumsianum. Diagnostic morphological characters are discussed and compared with those of related taxa. It can be easily distinguished from all taxa in the genus Prospero by its spring flowering time, synanthous leaves, and chasmophytic habit.
Scilla Hakkariensis, Sp. Nov. (Asparagaceae: Scilloideae): a New Species of Scilla L. From Hakkari (Eastern Anatolia)
(Publications Scientifiques Du Museum, Paris, 2020) Firat, Mehmet; Yildirim, Hasan
Scilla hakkariensis, sp. nov. (Asparagaceae), described herein as a new species to science, is endemic to the eastern Anatolian region of Turkey. It is related to S. libanotica Speta and S. mischtschenkoana Grossh., but clearly differs from them based on the morphological differences presented in the species description. Specifically, it is easily distinguished from both of them by its seeds without elaiosome. In addition, the conservation status, a distribution map, and notes on the biogeography and ecology of the new species are given.