Tiyoüre ile işlemden geçirilmiş GO nanoparçacıkları ile desteklenen PT nanokatalizörlerinin hazırlanması ve karaterizasyonu: doğrudan metanol yakıt hücrelerinin anodik sürecine uygulanması

In this thesis, Pt / graphene oxide (Pt / GO), Pt / reduced GO (Pt / 24 h thiourea-treated GO), Pt / 20 min thiourea-treated GO, Pt/ 2 h thiourea-treated GO, and Pt / 5 h thiourea-treated GO nanocatalysts were prepared for methanol oxidation reaction (MOR). The last three ones were synthesized for the first time. They were characterized by FTIR, UV-Vis spectroscopy, acid-base back titration, XRD, XPS, TEM and ICP-MS techniques. Their electrochemical properties and performances toward methanol oxidation reaction were defined by cyclic voltammetry (CV). FTIR studies indicated thiourea attachment on the surface of GO at the beginning of the treatment, and the reduction of GO in the longer treatment duration. Acid-base back titration exhibited the decrease in carboxyl and hydroxyl functional groups in consistence with FTIR results. XRD data demonstrated that all the prepared catalysts contain face-centered-cubic platinum nanoparticles in an average size of 3-4 nm. TEM images also confirmed this result. XPS analysis revealed that platinum exists in three different oxidation states, Pt(0), Pt(II), Pt(IV) in different ratios in each nanocatalysts. Electrochemical studies displayed that Pt / 20 min thiourea-treated GO has the highest performance toward methanol oxidation reaction (3.6 times higher than that of commercial E-TEK Pt / Vulcan XC-72 catalyst) due to its highest platinum utility (~94%), roughness factor (256), chemical (~80 m2 / g Pt) and electrochemical surface area ( ~ 75 m2 / g Pt).  M.S. - Master of Scienc

Hegel ve Whitehead’de süreç düşüncesi: yaşam ve canlılık

The purpose of this thesis is to clarify the thought of process in Hegel and Whitehead in the context of life and vitality. The concept of life has a special place for both Hegel and Whitehead. While for Whitehead, the situation of life in nature is the capital problem of philosophy and science, the concept of life serves as an analogy for Hegel’s own philosophical system, since it offers a model for thinking about development in general. The center of this study is the difficulty in unifying spirit and nature, in even more general terms, objective world and subjectivity. In this regard, this thesis will also focus on mechanism, dialectical logic, the mind-body problem and on what can be thought. The mind-body problem is actually an instance of the more general problem of “life-matter” which is related to whether biology can be completely reduced to physics without loss. Thus, this study will seek an answer to the question of what the vitality, life and organism are with regard to their processes of becoming or occurrence.Bu çalışmanın amacı, Hegel ve Whitehead’deki süreç düşüncesini yaşam ve canlılık bağlamında açıklığa kavuşturmaktır. Hayat kavramının hem Hegel hem de Whitehead için özel bir yeri vardır. Whitehead’e göre, doğadaki yaşamın konumu felsefe ve bilimin ana sorunu iken, yaşam, genel olarak gelişim hakkında bir model sunduğu için Hegel’in kendi felsefi sistemi için bir analoji görevi görür. Bu çalışmanın merkezindeki sorunsal, tin ile doğayı veya daha genel bir ifadeyle, nesnel dünya ve öznelliği birleştirmedeki zorluktur. Bu bağlamda, bu çalışma aynı zamanda mekanizma, diyalektik mantık, zihin-beden sorunu ve neyin düşünülebilir olduğuyla ilgilenecektir. Zihin-beden sorununun kendisi aslında biyolojinin tamamen kayıpsız olarak fiziğe indirgenip indirgenemeyeceğiyle ilgili olan daha genel “yaşam-madde” sorununun bir örneğidir. Bu sebeple bu tez, canlılığın, yaşamın ve organizmanın kendi oluşum süreçleri bağlamında ne oldukları sorusuna bir cevap arayacaktırM.A. - Master of Art

DFT STUDIES ON f-CNT AND COMPARISON WİTH EXPERIMENTAL RESULTS

DFT STUDIES ON f-CNT AND COMPARISON WİTH EXPERIMENTAL RESULT