Yazar "Aslan, Serdar" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Drilling of a hybrid Al/SiC/Gr metal matrix composites(Springer London Ltd, 2012) Altunpak, Yahya; Ay, Mustafa; Aslan, SerdarThe present study investigates the influence of cutting parameters on cutting force and surface roughness in drilling of Al/20%SiC/5%Gr and Al/20%SiC/10%Gr hybrid composites fabricated by vortex method. The drilling tests are conducted with diamond-like carbon-coated cutting tools. This paper is an attempt to understand the machining characteristics of the new hybrid metal matrix composites. The results indicate that inclusion of graphite as an additional reinforcement in Al/SiCp reinforced composite reduces the cutting force. The cutting speed and its interactions with feed rate are minimum. Feed rate is the main factor influencing the cutting force in both composites. The surface roughness value is proportional with the increase in feed rate while inversely proportional with cutting speed in both composites. For all cutting conditions, Al/20%SiC/10%Gr composite has lower surface roughness values than Al/20%SiC/5%Gr composite. The surface is analyzed using scanning electron microscope.Öğe Effect of alternative heat-treatment parameters on the aging behavior of short-fiber-reinforced 2124 al composites(Inst Za Kovinske Materiale I In Tehnologie, 2016) Altunpak, Yahya; Aslan, Serdar; Güler, Mehmet Oğuz; Akbulut, HatemThe 2124 Al alloy and a composite of the 2124 Al alloy reinforced with 20 % of volume fractions of delta-Al2O3 short fibers made by squeeze casting were subjected to controlled and systematic aging treatments. The materials were solution treated at (495, 525 and 555) degrees C. After quenching, the matrix alloy and the composite were artificially aged at (160, 170, 180 and 190) degrees C up to 36 h. The aging was monitored with hardness measurements and differential scanning calorimetry. The time required to reach the peak hardness of the composite matrix during a precipitation treatment was shorter than that for the unreinforced 2124 Al. An increase in the solution-treatment temperature resulted in an increase of the composite-matrix hardness. The delta-Al2O3-reinforced composite exhibits no grain-boundary melting, but appears to show incipient melting around short alumina fiber interfaces at temperatures above 525 degrees C. The highest HV value was obtained after solutionizing at 495 degrees C for 6 h, followed by water quenching and aging at 190 degrees C for 10 h for the unreinforced matrix alloy. In the case of the reinforced alloy the highest HV value was found after solutionizing at 555 degrees C for 6 h, quenching and aging at 170 degrees C for 12 h.Öğe A new record for Turkey: Michauxia nuda A.DC. (Campanulaceae)(2010) Aslan, Serdar; Vural, Mecit; Şahin, Bilal; Ergin, Esra; Kaya, Ömer FarukMichauxia nuda A.DC. (Campanulaceae) türü Türkiye’den (C8 Siirt) ilk defa kaydedilmiştir. M. nuda’nın tanıtıcı özellikleri, yetişme ortamı ve koruma durumu belirtilmektedir. Ayrıca bu türün, fotoğrafları ve yayılış alanını gösteren harita verilmiştir. Türün tip örneğinin numarası ile ilgili notlar verildi.Öğe Rangeland health, condition and biodiversity in Kırşehir province(2019) Mutlu, Ziya; Ünal, Sabahaddin; Mermer, Ali; Urla, Öztekin; Şahin, Bilal; Aslan, SerdarRangeland improvement and management have recently become more important that many new projects have been also initiated and conducted throughout Turkey. There is a great responsible for the provinces in the Central Anatolia Region on those implementation projects. In this framework, this study was designed that could contain vegetation surveys in representative sites for rangelands of Kırşehir province in 2008 year, at the same time their assessment, and conclusion were also performed too. The 36 rangeland sites were surveyed with the modified-loop method. The results of vegetation surveys were analyzed and determined rangeland condition and health classes for each sites. The vegetation cover was measured as 65.35%. The rates of decreasers and increasers cover were 11.54% and 35.26%, respectively. The studied sites numbers were one, 30 and 5 for good, fair, and poor conditions, respectively. The 35 sites of total sites were identified as fair and poor in condition based on the rangeland condition classes. On the other hand, 8 sites were found at healthy, 20 sites at risky and 8 sites at unhealthy in rangeland health categories. Total site numbers of the last two classes were 28.Rangeland biodiversity were calculated as 0.229 by Simpson’s index. Survey results showed that rangelandshave been overgrazed and seemed degradation. Firstly this trend should be stopped and secondly urgentmeasures should be implemented for restoration.
