Metalurji ve Malzeme Mühendisliği Bölümü/Makale Koleksiyonu
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Güncel Gönderiler
Öğe Doğalgaz Isıtma ve Sıhhi Tesi̇sat Teknoloji̇si̇ Programı Öğrenci̇leri̇ni̇n Endüstri̇ye Dayalı Öğreti̇m Hakkındaki̇ Görüşleri̇ ve Beklenti̇leri̇(Selçuk Üniversitesi, 2011 Mayıs) Kara, Memduh; Uyaner, MesutBu çalışmada Doğalgaz Isıtma ve Sıhhi Tesisat Teknolojisi Programı öğrencilerinin Endüstriye Dayalı Öğretimden neler bekledikleri, beklentilerinin karşılanma düzeyleri ve karşılaştıkları sorunlar ele alınmıştır. Araştırma kapsamına giren 1. sınıf ve 2. sınıf öğrencilerine anket uygulanmıştır. Araştırma sonucuna göre; işletme yetkilileri öğrencilerin kişisel becerilerine katkı sağlamaktadır. Endüstriye Dayalı Öğretim öğrencilerin kişisel gelişimine büyük bir etkisi olmaktadır ancak süresinin arttırılması gerekmektedir. Öğrencilerin iş yerinde kazandığı beceri okuldakine oranla daha fazladır. Öğrenciler okulda göremediği makine ve aletleri işletmede görmekte ve kullanabilmektedir. İşletme öğrencinin gelecekle ilgili iş bulma kaygısına tam olarak cevap verememektedir.Öğe The mechanical properties of composite materials recycled from waste metallic chips under different pressures(SPRINGER, 2019) Aslan, Abdullah.; Salur, Emin.; Gunes, Aydin.; Sahin, Omer Sinan.; Karadag, Hakan Burak.; Akdemir, Ahmet.The purpose of this study is to produce composite materials by utilizing the waste metallic chips. In this context, the metal matrix composite materials (MMCs) were produced at different production pressures and the effects of the different pressures on mechanical properties of MMCs were investigated. In the present investigation, spheroidal graphite cast iron (GGG-40) was used as reinforcement material in bronze (CuSn10) matrix system. The MMCs were produced by hot press with 20 wt% GGG-40 reinforcement ratio. The total time required for the production of one specimen was selected as 25 min and temperature was settled at 400 degrees C. In order to determine mechanical properties and consolidation mechanism of MMCs, Brinell and micro-Vickers hardness, porosity, compression and X-ray diffraction tests were conducted. In addition, microstructure views were examined to determine the consolidation quality of metallic chips. According to experimental results, it was observed that waste metallic chips can be successfully recycled into MMC final parts with approximately 40% porosity and almost 100% strength and 150% hardness with respect to bulk CuSn10 materials. Most of the presented studies in the literature present information about properties of MMCs fabricated by conventional production methods. However, no available data are found about the recycling of bronze-based MMCs which make this study more original. It is also shown in this study that waste metallic chips can be utilized by proposed recycling methodology, which is environmentally friendly in comparison with conventional recycling methods producing harmful gases for earth atmosphere.Öğe Solid particle erosion behavior of thermal barrier coatings produced by atmospheric plasma spray technique(TAYLOR & FRANCIS INC, 2019) Kaplan, Mustafa.; Uyaner, Mesut.; Avcu, Egemen.; Avcu, Yasemin Yildiran.; Karaoglanli, Abdullah Cahit.Thermal barrier coatings (TBCs) are commonly applied specifically for aerospace applications in which they are subjected to air-borne particles. Therefore, solid particle erosion behavior of all coating layer has been an important phenomenon and erosion behavior of various TBCs has been widely investigated in literature. In the present study, CoNiCrAlY and yttria stabilized zirconia (ZrO2 + 8% Y2O3) powders were deposited on Inconel 718 nickel based super alloy substrate. Atmospheric plasma spraying technique was applied for the deposition of the metallic bond coat and the ceramic top coats. Erosion tests were carried out under various particle impingement angles with an air jet erosion tester. Afterwards, eroded surfaces of the specimens were investigated with a three-dimensional (3D) optical surface profilometer (noncontact) and scanning electron microscope. The erosion rates, the areal surface roughness values, the 3D surface topographies, and the surface morphology of the specimens were evaluated based on the particle impingement angle to understand the solid particle erosion behavior of the produced coatings. The maximum erosion rates occurred at 60 degrees impingement angle which is an indication of semi-ductile/semi-brittle erosion behavior. Furthermore, the surface roughness values and surface topographies also dramatically varied depending on the impingement angle. Deeper and wider erosion craters formed at 60 degrees impact angle and the erosion craters were visualized by profilometer analysis.Öğe Nickel fluoride as a surface activation agent for electroless nickel coating of anodized AA1050 aluminum alloy(ELSEVIER SCIENCE SA, 2019) Kocabaş, M.; Örnek, C.; Curioni, M.; Cansever, N.In this study, the use of nickel fluoride tetrahydrate (NiF2 center dot 4H(2)O) as a surface activator and sealant at the same time for the coating of electroless nickel-phosphorus (Ni-P) on anodized aluminum alloy AA1050 is proposed. The usage of the activator resulted in more efficient deposition of Ni-P, improved adhesion properties, and increased wear and friction behavior as opposed to non-activated conditions. Scanning electron microscopy (SEM) and confocal laser microscopy (CLM) analyses of ultramicrotome-cut cross sections of Ni-P coated specimens, surface-activated by NiF2 center dot 4H(2)O, revealed a more well-structured metal-coating interface as opposed to non-activated conditions.Öğe Investigating the effect of gold nanoparticles on hydatid cyst protoscolices under low-power green laser irradiation(TURKISH SURGICAL ASSOC, 2019) Çolak, Bayram.; Aksoy, Faruk.; Yavuz, Selman.; Demircili, Mehmet Emin.Objective: Various scolicidal agents are applied for the destruction of protoscolices in cysts media. Undesirable complications of the scolicidal agents limit the techniques to treat the cyst disease. Therefore, new non-toxic scolicidal agents are needed. Upon laser light irradiation, the photothermal gold nanoparticles (AuNPs) convert the absorbed laser light into heat through photothermal effect which kills the surrounding protoscolices by rising the temperature of the cysts media. In this study, we introduced biocompatible AuNPs as a non-toxic scolicidal agent to cure liver hydatid cysts. Material and Methods: The protoscoleces were collected from the livers of naturally infected sheeps. In each experimental group, 1.5 mL suspensions of hydatid liquid containing protoscolices were added to test tubes. The test tubes were divided into five groups. Control, AuNPs only, Green laser only, High-dose AuNPs + laser and Low-dose AuNPs + laser groups. Two concentrations (0.4 and 0.8 mL) of AuNPs and three laser powers (30, 50, 150 mW) were applied for 30, 60 and 120 minutes to the groups. Then the ciysts liquid assessed under a light microscope and determined the viability of protoscoleces. Results: Protoscolices in high-dose AuNPs group were destructed up to 89.30% deaths under 150 mW laser power for 120 minutes. However, negligible cell deaths were observed in cases where only AuNPs added or only laser irradiated groups. Increasing the dose of AuNPs or laser power or duration of aplication increased the protoscolosidal death rate. Conclusion: In the study, we have successfully demonstrated that the AuNPs are an effective therapeutic and scolicidal agent to cure hydatid cyst disease under laser irradiation.Öğe In situ reduction of chloroauric acid (HAuCl4) for generation of catalytic Au nanoparticle embedded triazine based covalent organic polymer networks(ROYAL SOC CHEMISTRY, 2019) Dursun, Sami.; Yavuz, Emine.; Çetinkaya, Zeynep.Covalent-organic polymer networks (COPNs) have been used as catalyst supports due to their stable and favorable structure. Herein, a simple synthetic route was applied to generate Au@COPN-1 hybrids via in situ reduction of gold ions with no additional reducing agent. Synthesized novel COPN-1 was mixed with different concentrations of HAuCl4 which resulted in Au@COPN-1 with varying sizes of Au nanoparticles in a controlled manner. The microstructural and morphological features of COPN-1 and Au@COPN-1 were characterized in detail using FT-IR, C-NMR, elemental analysis, UV-Vis, XRD, TEM, BET, and TGA. It is noteworthy that the red-shifted LSPR peaks of Au nanoparticles produced with increasing concentrations of HAuCl4 indicated an increase in the particle size of the Au nanoparticles as justified by TEM images. The optimum catalytic activity of Au@COPN-1 was obtained when 4.6 x 10(-3) mM HAuCl4 was used, which led to the complete reduction of 4-nitrophenol within 16 minutes with excellent recyclability for more than 5 catalytic cycles, giving yields over 94%. Moreover, the non-aggregation of nanoparticles in the reused catalyst further confirmed the stability of the prepared catalysts. Consequently, these results indicated that in situ synthesis of AuNPs inside the COPN-1 matrix produces a promising catalyst platform for the reduction of aromatic nitro compounds, for example, for the degradation of one of the most common persistent organic pollutants 4-nitrophenol, as shown here. In addition, the Au@COPN-1 hybrid system showed good biocompatibility at appropriate doses confirmed by a dynamic real-time cell analysis system which can be used in various medical applications, such as drug delivery, in the future.Öğe Experimental study and analysis of machinability characteristics of metal matrix composites during drilling(ELSEVIER SCI LTD, 2019) Salur, Emin.; Aslan, Abdullah.; Kuntoglu, Mustafa.; Gunes, Aydin.; Sahin, Omer Sinan.In this study, the metal matrix composite materials were produced by hot press with various production parameters. The drilling experiments were performed on computer numerical control vertical machining centre without cutting fluid. Analysis of variance (ANOVA) was carried out in order to determine the effects of the production parameters on thrust force and surface roughness of metal matrix composites drilled with different feed rate. The effect of production parameters such as temperature, pressure and reinforcement ratio were investigated, and their effects were presented. The optimal level for each production parameters was determined by 'Maximize the S/N ratio approach with a Taguchi design'. The test results revealed that the reinforcement ratio was the main factor affecting the surface roughness of the metal matrix composites for both feed rate. However, same singularity was not matter on thrust force due to close contribution rates of production parameters and high error rates of analysis. In literature, an increase on the thrust force and the surface roughness values was reported as the feed rate increased during machining. Nevertheless, in our MMCs system, the thrust force and the surface roughness values were in tendency of declination / as the feed rate increased which makes this study more novel research.Öğe Effects of the number of fatigue cycles on the hoop tensile strength of glass Fiber/epoxy composite pipes(SPRINGER, 2019) Kara, Memduh.; Kirici, Muhammed.; Cagan, Suleyman Cinar.Glass fiber-reinforced plastics (GFRPs) composite materials are widely used in many areas due to their superior properties such as high strength, corrosion resistance against many chemicals, duplicate production, the possibility of production in very large dimensions, and lighter weight than metals and alloys. As the use of GFRP pipes increases, many test methods are performed to determine their mechanical properties. Hoop tensile strength of GFRP pipes was determined by hoop tensile strength test according to ASTM D 2290 standard, and fatigue tests of GFRP pipes were carried out by applying internal hydraulic pressure according to ASTM D 2992 standard. In this study, six-layered E-glass epoxy composite pipes which were manufactured by the filament wound method for winding angle +/- 55 degrees were subjected to fatigue tests at the different number of cycles, and hoop tensile strength of fatigued pipes was determined. The samples were subjected to a fatigue test at a stress ratio of 0.05 and a frequency of 0.42 Hz according to ASTM D 2992 standard. Fatigue tests were performed on samples with a stress value of 35% static burst pressure. As a result of experiments, the effects of the number of fatigue cycles on the hoop tensile strength of the GFRP pipes were investigated, and the damage occurred in the GFRP pipes was evaluated. The increase in the number of cycles from the fatigue tests applied to the samples resulted in a reduction in the tensile strength of the samples.Öğe Isıl işlem süresinin ötektik-altı Al-Si alaşımlarının mekanik özelliklerine etkisi(2018) Çevirir, Yusuf; Necip, Sertan; Yıldırım, Mehmet% 7,29 Si oranına sahip Al-Si döküm alaşımının yapısal ve mekanik özelliklerine ısıl işlem süresinin etkisisistematik olarak incelenmiştir. Numunelere 200C sıcaklıkta 1, 2, 4, 16 ve 64 saat ısıl işlemuygulanmıştır. Mikroyapı ve faz analizleri optik mikroskop ve X-ışınları kırınımı ile termal özellikleridiferansiyel taramalı kalorimetreile mekanik özellikleri ise çekme ve sertlik ölçümleri kullanılarakgerçekleştirilmiştir. Dökülmüş haldeki alaşımın mikroyapısı birincil kristalleşmiş Al dendritleri ve kaba Siötektiğinden meydana gelmektedir. Uygulanan ısıl işlemin mikroyapısal özelliklere çok önemli bir etkisiolmamasına rağmen çekme dayanımı, sertlik ve uzama gibi mekanik özellikler de ciddi değişimlere yolaçtığı gözlemlenmiştir. En yüksek uzama değeri ve en düşük çekme dayanımı ısıl işlem görmemiş dökümalaşımında gözlemlenmiştir. En düşük uzama değeri ve en yüksek çekme dayanımı ise 4 saat ısıl işlemgörmüş numunede gözlemlenmiştir. Dayanım ve sertlik 0-4 saat arası sürelerde artış gösterirken, 4-64saat arası sürelerde ise azalma eğilimindedirÖğe Filaman sarım ile üretilen CTP kompozit borularda tabaka sayısının teğetsel gerilme dayanımına etkisi(2017) Kara, Memduh; Uyaner, MesutCam takviyeli plastik (CTP) kompozit boruların diğer boru çeşitlerine göre birçok üstün özelliği vardır. Bunlar, kimyasal maddelerin oluşturacağı korozyona karşı dayanım, olumsuz hava koşullarına ve UV ışınlara karşı dayanım, istenilen boyutlarda seri üretim imkânı ve uzun ömürlü olması gibi özelliklerdir. Bütün bu özellikleri nedeniyle petrol ve doğalgaz iletim hatlarında ve kimyasal akışkanların iletim hatlarında yaygın olarak kullanılmaktadır. Kullanım alanı hızla artmakta olan CTP kompozit boruların mekanik özelliklerinin belirlenmesi için birçok test yöntemi geliştirilmiştir. Cam takviyeli plastik boruların teğetsel gerilme dayanımı; ASTM D 1599 standardına göre hidrolik basınç testi ve ASTM D 2290 standardına göre halka çekme testi ile tespit edilmektedir. Bu çalışmada 6, 8 ve 10 tabakalı olacak şekilde filaman sarım yöntemiyle 55 sarım açısında üretilen Ecamı/epoksi kompozit boruların teğetsel gerilme dayanımı her iki yöntem kullanılarak belirlenmiştir. Her iki yöntemden elde edilen sonuçlar birbirleriyle karşılaştırılarak değerlendirilmiştir. Ayrıca CTP kompozit borularda statik iç basınç patlatma testi esnasında ve halka çekme testi esnasında oluşan hasar gelişimi değerlendirilmiştir.Öğe One-Pot Facile Synthesis of PEGylated Au Nanoparticles in an Aqueous Media(ELSEVIER SCIENCE SA, 2012) Çamlı, Şevket Tolga; Büyükserin, Fatih; Yavuz, T. Cafer; Yavuz, Mustafa SelmanWe describe a facile protocol for the synthesis of PEGylated Au nanoparticles by simply mixing aqueous solutions of HAuCl4 and oligo(ethylene glycol) ethyl ether methacrylate. This method was applied to generate uniform multiply-twinned Au nanostructures of similar to 21 nm in diameter with high yields. Our proposed mechanism indicates that the generation of primary alcohol intermediates from the nucleophilic addition reaction of water (nucleophile) with AuIII-vinyl complex is responsible for the reduction of gold ions. This protocol was also used to synthesize Ag nanoparticles and small aggregates of Pd nanoparticles. Due to the exclusion of sophisticated synthesis of PEG containing stabilizers, additional surfactants, or reducing agents, this approach provides a remarkably simple, versatile, and environmentally benign protocol to prepare PEGylated noble-metal nanocrystals. A comparative BSA adsorption study proved the lack of non-specific binding, a common obstacle in designing biocompatible nanoparticles.Öğe The Cost Analysis of Satellite Images for Using in Gis by the Pert(International Society for Photogrammetry and Remote Sensing, 2004) Çay, T.; İşcan, F.; Durduran, S.S.The method of collecting, saving, storing of geographical information with and without a location on the earth, the other data related to these information, and to get the result in the quickest way by means of analyzing them through a security can be managed by Geographical Information System (GIS). The important one of the basic elements of Geographical Information System comes firstly DATA. In collecting data there are various methods of them, GPS or classical measurement, Aerial Photographs, Satellite Images and Digitizing of Map and Documentary are the principle methods. The cost calculation of the provision of satellite images by evaluating through Image Processing is a determinant critical point in the selecting of the method of data collection up to the stage of using them as a cadastral map for the Geographical Information System. In this study, in selecting of Satellite Images that is one of the methods of collecting data in order to be cadastral map for the Geographical Information System, the result of cost analysis carried out by the Method of Program Evaluation and Review Techniques (PERT) will be introduced.
