Hollow glass spheres (HGS) have many application areas in the field of composite production due to their lightweight property together with having a sufficient strength. This study has the focus on adding the HGS to epoxy resin in different concentrations. The surface of the glass spheres were modified with silane prior to resin casting. The material characterization of the HGS filled epoxies was based on the silane presence and the HGS addition. Dynamic mechanical analysis was applied to observe the mechanical properties depending on the temperature of the composites. Morphological investigations were made to determine the interfacial adhesion between epoxy and the HGS. As a result of these, it was obtained that the HGS addition enhanced the stiffness of the material without a sharp reduction in the ductility. Silane was observed to be successful in improving the storage modulus below the glass transition temperature (Tg). However, the reduction in Tg was observed in high amount of modified HGS loading due to their interfering effect on the crosslink system of the epoxy.
In this study, wear behavior of ultrasonic impact treated S235JR steel was investigated. Samples were peened for different times (5, 15 and 30 minutes) by ultrasonic impact treatment. It was found that triple layers (nanocrystallization, plastic deformation and residual stress) formed on the treated surface. The thickness of the layers treated samples increased with increasing treatment time. It was also determined that surface roughness of treated samples decreased with increasing treatment time. All treated samples have significant surface hardness. Nanocrystallization layer on top of the treated surface has the highest hardness values in comparison with the hardness of the other layers. The treatment increases not only surface hardness, but also wear resistance of all treated samples. The maximum wear resistance was observed for the 30 min treated samples due to the high hardness and thickness of the nanocrystallization layers.
Diamond tools are widely used in cutting process of natural stones. In the manufacturing process of diamond tools, matrix material can be sintered via different sintering methods such as spark plasma sintering (SPS), hot isostatic pressing (HIP) and conventional sintering (CS). CS method provides higher production capacity and lower cost when compared to other sintering methods, but mechanical properties are inferior to other sintering methods. Recent studies have the aim to obtain similar performance level as achieved by means of CS method. In this study, samples were prepared with three different compositions to be used for the CS method and characterized to evaluate their performance as a diamond bead matrix material. Experimental results showed that a study can be conducted to reach similar performances with Co matrix by using Ni matrix, and a high copper rate in matrix is undesirable since diamond tools are exposed to impact forces.
In the present study, abrasive wear and frictional behaviors of polyoxymethylene were investigated experimentally. To realize this, a test apparatus was designed and fabricated. Wear tests were carried out under dry conditions at room temperature. A central composite design was used to describe response and to estimate the parameters in the model. An empirical model had been developed to predict wear loss as a function of applied load and sliding distance. Friction coefficient decreases with increase in applied load. On the other hand, it is also found that friction coefficient increases with the increase in sliding velocity.
This study describes Marshall G. Hodgson's thinking about the study of Islamic history studies in his work entitled The Venture of Islam. The research used in this study is analytical descriptive, which is a study that examines Marshall G.S Hodgson's thinking about Islamic history studies then parses and identifies the patterns of thought. According to Marshall G. S. Hodgson the history of Islam is the result of the ever-changing setting shaped by the Islamic tradition. In addition, it is also the result of a process of accomodation or acculturation from other pre-existing cultural traditions. Based on this view, and in the context of conversations about Islamic civilization, Marshall G. S. Hodgson emphasized the importance of seeing cultural continuity occurring at the level of religion, expressed by Muslims. Marshall G.S. Hudgson in seeing the reality of Islam in the world classifies in three forms of Islamic phenomena as the object of study. First, the phenomenon of Islam as a doctrine (Islamic), second, the phenomenon when the doctrine enters and processes in a cultural society (Islamicate) and manifests itself in a particular social and historical context. And thirdly, when Islam became a phenomenon of the political "world" in state institutions (Islamdom).
Lathyrus L. (Papilionoideae, Fabaceae) ekonomik, ekolojik ve genetik olarak cicekli bitkilerin en onemli cinsleri arasinda kabul edilir ve Turkiye’nin bulundugu Guneybati Asya cesitlilik merkezidir. Lathyrus cinsinde yer alan turlerin anatomik ve mikromorfolojik ozellikleri sadece birkac calismada bildirilmistir. Bu yuzden, bu guncel calismada bu cinsin Lathyrus seksiyonuna ait L. cassius Boiss., L. chloranthus Boiss. & Balansa, L. cicera L., L. hirsutus L. ve L. sativus L. turlerinin karsilastirmali anatomisi ve yaprak epidermal mikromorfolojisi tur ayriminda anatomik ve mikromofolojik karakterlerin taksonomik onemini degerlendirmek icin isik ve taramali elektron mikroskobu kullanilarak ayrintili bir sekilde arastirilmistir. Elde edilen sonuclar bazi anatomik ve mikromorfolojik karakterlerin tur duzeyinde ayrim icin faydali oldugunu gostermistir. Taksonomik oneme sahip anatomik ve mikromorfolojik ozellikler sunlardir: kokteki isin siralarinin sayisi, govdenin enine kesitteki sekli, kanat uzunlugunun govdenin capina orani, her bir kanattaki iletim demetlerinin sayisi, yapraktaki epidermal hucrelerin ve bunlarin antiklinal duvarlarinin sekli ve tuylerin varligi.