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Öğe The varieties and characteristics of grapes grown in Southeast Anatolia Region(Batman Üniversitesi, 2020-12-31) Levent, Abdulkadir; Demir, ZülküfGrape is a fruit, called Vitis. Turkey replaces in the first sixth in growing grape, in the world. Grape has a significant place in the food industry. The antioxidants in grape seed have the effect of preventing and treating many diseases. In Turkey, the percentages of grapes, consumed in the form of wort, is about 30 %, annually. The 25 % of grape garbage is seeds. Approximately 3-6 % of grapes seeds (44000 tons) wasted annually. The foreseeing designing and manufacturing the grape squeezing machine will facilitate the work of the grape grower and will achieve the grape seeds to the economy. While the sieve diameter of grape seeds separator, separated the seeds from the garbage of the grape will be less than or equal to 2 mm (≤2 mm), the garbage from the wort is greater than or equal to 8.5 mm (≥8.5 mm), according to the seeds geometrical dimensions, gained.Öğe Investigate the effect of pre-drilling in friction drilling of A7075-T651(Taylor & Francis, 2014-04-28) Demir, Zülküf; Özek, CebeliFriction drilling is a non-traditional hole achieving method that is a clean, chip-less process, which is called thermal drilling, form drilling, flow drilling, and friction stir drilling. In this study pre-drilling friction drilling was investigated for improving the bushing shape of A7075-T651, which is a brittle cast material. During the process, surface roughness and bushing shapes were analyzed and generated frictional heat was measured by the virtue of thermocouples. Experiments were carried out to 4mm and 6mm in thicknesses of A7075-T651 aluminum alloy at 1200, 1800, 2400, 3000, and 3600 rpm spindle speeds, 20, 40, 60, 80, and 100 mm/min feed rates with using high-speed steel rotating conical tool, whose diameter is 8 mm. Consequently, the bushing shapes were advanced without cracks and petal formation in pre-drilling Friction drilling in comparison with without pre-drilling process. With increasing pre-drilled hole diameter the generated frictional heat was decreased. The achieved temperature was realized to be 1/2-1/3 of the melting temperature of the workpiece. Surface roughness values were decreased with decreasing or increasing both spindle speed and feed rate correspondingly.Öğe A7075-T651 alaşımının sürtünmeli delinmesinde takım geometrisinin etkisinin araştırılması(Batman Üniversitesi, 2015) Demir, ZülküfSürtünmeli delme, kendi ekseni etrafında dönen konik bir takım ile iş parçası arasında sürtünme sonucu oluşan ısının etkisiyle malzemenin yumuşaması ve takımın dalması şeklinde uygulanan, geleneksel olmayan delik delme yöntemidir. Bu deneysel çalışmada, 4 ve 6 mm kalınlığındaki A7075-T651 alüminyum alaşımı, koniklik açıları 24o, 36o, ve 48o, silindirik böle uzunlukları (hl) 8, 16 ve 24 mm, çapı 8 mm olan HSS takımlar ile 1200, 1800, 2400, 3000 ve 3600 d/d devirlerinde, 20, 40, 60, 80 ve 100 mm/dak ilerleme değerlerinde sürtünmeli delinmişlerdir. Çalışmada takımın geometrisini oluşturan uç, konik, silindirik ve omuz bölgelerinin işlem üzerindeki etkileri araştırılmıştır ve meydana gelen sıcaklık değerleri ve kovan biçimi araştırılmıştır. İşlemde başlangıç deformasyonuna takım ucunun sebep olduğu, sürtünme ısısının konik bölgenin devire ve ilerlemeye bağlı olarak arttırdığı tespit edilmiştir. Ayrıca kovandaki çatlakların konik ve silindirik bölgenin geometrisi tarafından etkilendiği, omuz çapının yetersiz olması veya takımın silindirik bölgesine ergimiş malzemenin yapışarak yığılması, pul biçiminin bozulmasına neden olduğu görülmüştür.Öğe A7075-T651 alaşımının sürtünmeli delinmesinde ön-delik çap ve derinliğinin yüzey pürüzlülüğüne ve kovanın geometrik boyutlarına etkisinin araştırılması(Batman Üniversitesi, 2017) Demir, Zülküf; Adıyaman, Oktay; Yakut, Rifat4 mm ve 6 mm kalınlıklarına sahip, geleneksel ön-delinmiş,A7075-T651 alüminyum alaşımı, koniklik açısı (β) 36o , silindirik bölge uzunluğu (hl) 16 mm, çapları 8 ve 10 mm olan HSS takımlar ile 3000 d/dak dönme devrinde, 60 mm/dak ilerleme değerinde sürtünmeli olarak delinmişlerdir. Bu çalışmada ön-delik çapının ve derinliğinin yüzey pürüzlülüğüne, kovan yüksekliğine ve kovanın çeper kalınlığına etkisi araştırılmıştır. Elde edilen deneysel çalışmalardan ön-delik çapının takım ucunun son çapına, ön-delik derinliğinin ise takım ucunun (hc) yüksekliğine yakın olduğu durumlarda deformasyon azaldığından dolayı yüzey pürüzlülüğünün azaldığı, sürtünmeli delme işlemi sırasında ise yumuşamış malzeme düzenli bir şekilde aktığından kovanın çeper kalınlığı ve kovan yüksekliğinin arttığı tespit edilmiştir. En uygun ön-delik çapı 8 mm çapındaki delik için 2.5-3 mm, 10 mm çapındaki delik için ise 3-3.5 mm olduğu, ön-delik derinliğinin ise 2-3 mm arasında olduğu görülmüştürÖğe Model and formulation in grinding mechanism having advanced secondary rotational axis(SAGE, 2019-04-15) Adıyaman, Oktay; Demir, Zülküf‘‘Grinding Mechanism having Advanced Secondary Rotational Axis’’ is one of the newer plane surface grinding methods that has an uncommon abrasion mechanism. Unlike conventional methods, in Grinding Mechanism having Advanced Secondary Rotational Axis, there are two rotations of a wheel. The first rotation is the same as the conventional grinding methods, which is the circumferential rotation. The other rotation is the newly developed axial rotation, where the wheel rotates around itself perpendicular to its radial axis. In the grinding process, the grinding force, energy, power, and temperature are directly related to the material removal rate. In this article, the chip model in Grinding Mechanism having Advanced Secondary Rotational Axis was addressed and material removal rate was reformulated. The new chip ratio formula was adapted to the grinding force, energy, power, and temperature in the conventional plane surface grinding method. The chip formed in the conventional plane surface grinding method consists of two-dimensional xy plane. In Grinding Mechanism having Advanced Secondary Rotational Axis, on the other hand, the chips consist of threedimensional xyz plane. The reason behind this is the second rotation obtained in Grinding Mechanism having Advanced Secondary Rotational Axis (axial rotational motion). The chip model was obtained from the combination of two rotations in Grinding Mechanism having Advanced Secondary Rotational Axis. As a result, the resulting chip model increased the material removal rate only slightly and this increase was negligible. Accordingly, an increase in grinding force, energy, power, and temperature was observed at negligible rates.Öğe An experimental investigation on bushing geometrical properties and density in thermal frictional drilling(Multidisciplinary Digital Publishing Institute (MDPI), 2018-12-18) Demir, Zülküf; Özek, Cebeli; Bal, MuhammedIn thermal friction drilling (TFD) operations, the geometrical dimensions of bushing shape, height and wall thickness are the most vital consequences, since these increase the connecting length and strength. In this paper, AA7075-T651 aluminum alloys with 2, 4, 6, 8, and 10 mm thicknesses were drilled with the TFD process in order to investigate density, volume ratio, and height and wall thickness of the bushings. The experiments were conducted at constant spindle speed and feed rate conditions by using High Speed Steel (HSS) conical tools of 5, 10, 15, and 20 mm in diameter. It was experimentally found that the bushing height and the wall thickness had a tendency to increase linearly with the increase in both material thickness and tool diameter. The effect of tool diameter was found to have more influence on the measurable values than the thickness of the drilled material. The density of the bushing changed trivially. Approximately 70-75 percent of the evacuated material formed the bushing shape in TFD operations.Öğe An experimental investigation of the effects of point angle on the high-speed steel drills performance in drilling(SAGE, 2018-11) Demir, ZülküfThe differences in the cutting speed are a serious problem along the cutting edge of the drill, in drilling operations. This problem can partly be solved reducing the length of the cutting edge via changing the drill point angle. In addition, in this study, the effect of point angle, feed rate, and cutting speed on drilling is investigated. For identifying the optimum cutting parameters, AISI 1050 steel alloy was selected as the experimental specimen, these specimen were pre-drilled 5 mm in diameter due to eliminating the effect of the chisel edge. In the experiments, the holes were drilled only at a depth of 10 mm in order not to give any harm to the dynamometer while measuring thrust force. For this aim, in drilling process, drills with point angle of 100°, 118°, 136°, 154°, and 172° were selected. In conclusion, the thrust force, the tool wear, and the surface roughness linearly decreased with increasing point angles due to less removal chip area, in per revolve of the tool. However, the thrust force, the tool wear, and the surface roughness were adversely affected at higher feed rates and lower cutting speeds. The hole dimensional accuracy decreased at lower feed rates and cutting speeds but at higher point angles and concurrently at higher feed rates but lower point angles and cutting speeds. However, the hole dimensional accuracy showed more decisiveness at 118° than other point angles, while the highest dimensional accuracy values recorded at 136° point angle, at higher cutting speeds.Öğe An investigation of the effect of parameters and chip slenderness ratio on drilling process quality of AISI 1050 steel(Hindawi, 2018-05-08) Demir, Zülküf; Yakut, RıfatThe chip slenderness ratio is a vital parameter in theoretical and applicable machining operations. In predrilled drilling operations of AISI 1050 steel alloy, HSS drills were employed, and the effect of the selected parameters on the chip slenderness ratio and also the effect of the chip slenderness ratio on the thrust force, surface roughness, drilled hole delamination, tool wear, and chip morphology were investigated. The major parameters, influential on the chip slenderness ratio, were feed rate and point angle, while spindle speed was too small to be negligible. With increasing the chip slenderness ratio, the thrust force and the tool wear decreased, which resulted in appropriate chip morphology, but there were increases in surface roughness. However, the chip slenderness ratio had no effect on the drilled hole delamination.
